|Record 1 of 117 in AGRICOLA (1998-2001/09)
AN: IND 22433568
AU: Lequarre,-A.S.; Feugang,-J.M.; Malhomme,-O.; Donnay,-I.; Massip,-A.; Dessy,-F.; Langendonckt,-A.-van.
TI: Expression of Cu/Zn and Mn superoxide dismutases during bovine embryo development: influence of in vitro culture.
SO: Mol-reprod-dev. New York, N.Y. : Wiley-Liss, Inc. Jan 2001. v. 58 (1) p. 45-53.
CN: DNAL QP251.M64
IS: ISSN: 1040-452X
DE: cattle-. embryo-culture. embryonic-development. superoxide-dismutase. copper-. zinc-. manganese-. temporal-variation. oocytes-. embryos-. superovulation-. messenger-rna. transcription-.
Record 2 of 117 in AGRICOLA (1998-2001/09)
AN: IND 22017528
AU: Campbell,-M.H.; Miller,-J.K.; Schrick,-F.N.
TI: Effect of additional cobalt, copper, manganese, and zinc on reproduction and milk yield of lactating dairy cows receiving bovine somatotropin.
SO: J-dairy-sci. Savoy, Ill. : American Dairy Science Association. May 1999. v. 82 (5) p. 1019-1025.
CN: DNAL 44.8-J822
IS: ISSN: 0022-0302
DE: dairy-cows. somatotropin-. mineral-supplements. organocopper-compounds. organic-compounds. cobalt-. manganese-. zinc-. chelates-. concentrates-. chemical-composition. diets-. estrus-. repeat-breeders. female-fertility. postpartum-interval. corpus-luteum. milk-yield. body-condition. blood-plasma. insulin-. urea-.
AB: The objective of this study was to determine whether organically complexed Co, Cu, Mn, and Zn would improve the reproductive performance and milk and milk component production in lactating dairy cows that began receiving bovine somatotropin in the ninth week of lactation. Holstein (n = 50) and Jersey (n = 10) cows were blocked by breed, lactation number, and incidence of retained fetal membranes. Two diets assigned within blocks and fed from parturition until 154 d of lactation were control or control supplemented daily with 26 mg of Co as Co glucoheptonate, 125 mg of Cu as Cu-Lys, 199 mg of Mn as Mn-Met, and 359 mg of Zn as Zn-Met. Cows were fitted with electronic pressure-sensing devices in the second week of lactation for detection of estrus. Ovarian structures were determined via transrectal ultrasonography at 7-d intervals from parturition until observation of the first corpus luteum. Blood samples were taken at 7-d intervals and analyzed for plasma concentrations of progesterone, insulin, and urea nitrogen. Onset of luteal activity was identified by progesterone concentrations greater than or equal to 1 ng/ml. Retained fetal membranes increased days to first estrus (detected via electronic estrous detection), first luteal activity, and first corpus luteum in control cows but not in supplemented cows. Days to first observed estrus were greater for control cows than for supplemented cows. Days to first service, days open, days from first service to conception, services per conception, milk yield, milk components, and somatic cell counts were similar for control and supplemented cows. Supplementation with complexed trace minerals effectively reduced days to first.
Record 3 of 117 in AGRICOLA (1998-2001/09)
AN: IND 21981149
AU: Haaf,-A.; LeClaire,-L.-III.; Roberts,-G.; Kent,-H.M.; Roberts,-T.M.; Stewart,-M.; Neuhaus,-D.
TI: Solution structure of the motile major sperm protein (MSP) of Ascaris suum--evidence for two manganese binding sites and the possible role of divalent cations in filament formation.
SO: J-mol-biol. London ; New York : Academic Press, 1959-. Dec 18, 1998. v. 284 (5) p. 1611-1624.
CN: DNAL 442.8-J8224
IS: ISSN: 0022-2836
DE: ascaris-suum. spermatozoa-. animal-proteins. molecular-conformation. binding-sites. manganese-. magnesium-. metal-ions. nuclear-magnetic-resonance-spectrum. binding-. polymerization-. polymers-.
Record 4 of 117 in AGRICOLA (1979 - 1984)
AN: FNI 83002024
AU: Leach,-R.M.; Lilburn,-M.S.
TI: Manganese metabolism and its function.
SO: World-Rev-Nutr-Diet. Basel : S. Karger. 1978. v. 32 p. 123-134.
CN: DNAL 389.1-W892
IS: ISSN: 0084-2230
AB: Abstract: Manganese (Mn) is essential for growth, reproduction, prevention of skeletal abnormalities, and congenital ataxia. Mn homeostasis is maintained by excretion via bile and intestinal tract rather than at the site of absorption. Pathways are fairly specific, but genetics and hormones can influence metabolism. Mn usually localizes in the cell's mitochrondria. Mn is the metal cofactor (preferred) for a number of glycosyltransferases which provides the link between biochemical function and deficiency symptoms. Mn also plays an important role in carbohydrate, lipid, and brain metabolism. (kbc).
Record 5 of 117 in AGRICOLA (1992-1997)
AN: IND 20571484
AU: Lapointe,-S.; Ahmad,-I.; Buhr,-M.M.; Sirard,-M.A.
TI: Modulation of postthaw motility, survival, calcium uptake, and fertility of bovine sperm by magnesium and manganese.
SO: J-dairy-sci. Champaign, Ill. : American Dairy Science Association. Dec 1996. v. 79 (12) p. 2163-2169.
CN: DNAL 44.8-J822
IS: ISSN: 0022-0302
DE: dairy-bulls. spermatozoa-. motility-. semen-diluent-additives. metal-ions. magnesium-chloride. manganese-. mucus-. penetration-. calcium-ions. survival-. in-vitro. fertilization-. capacitation-. heparin-.
AB: Because Mg2+ and Mn2+ are potent stimulators of motility through the stimulation of adenylate cyclase activity, the current study was undertaken to modulate the fertilizing ability of bovine semen by incorporation of various concentrations of those two salts in extenders before freezing. Motility analysis at 6 h in vitro showed a positive effect of MgCl2 in a dose-dependent manner from 0.5 to 5 mM (31 to 50%). Manganese at the concentration of 0.1 mM also supported good sperm motility (53%) compared with that of the control (28%). Although survival was increased, no detrimental effects were seen on the number of sperm that penetrated mucus of cows in estrus. The intracellular Ca2+ concentration of sperm was very different across treatments after thawing; spermatozoa that were extended with 2 mM MgCl2 and 0.5 mM MnCl2 possessed the highest concentrations at thawing. Four hours later, in the presence of Ca, spermatozoa that were extended in 0.1 mM MnCl2 showed the highest uptake. In the presence of Ca and heparin, spermatozoa that were extended in different amounts of Mg showed Ca2+ concentrations that increased in a dose-dependent manner. This effect was negated by glucose. Functional fertilizing capacity was also evaluated by in vitro fertilization, and the different treatments did not show any detrimental effects. In summary, 5 mM MgCl2 and 0.1 mM MnCl2 both have beneficial effects for the maintenance of sperm motility without detrimental effects on mucus penetration and fertilizing ability. Furthermore, these treatments do not prevent subsequent Ca2+ uptake in response to heparin. These in vitro studies are potentially a good sorting system to predict the.
benefits of extender modifications.
Record 6 of 117 in AGRICOLA (1992-1997)
AN: IND 92056481
AU: Christianson,-S.L.; Peo,-E.R.-Jr.
TI: Manganese--critical trace mineral for sows.
SO: EC-Coop-Ext-Serv-Univ-Nebr. Lincoln, Neb. : The Service. 1991. (91-219) p. 15-17.
CN: DNAL 275.29-N272EX
DE: sow-reproduction. manganese-. sow-milk. estrous-cycle. litter-performance.
Record 7 of 117 in AGRICOLA (1970 - 1978)
AN: CAIN 789082032
AU: Hidiroglou,-M; Ho,-S-K; Standish,-J-F
TI: Effects of dietary manganese levels on reproductive performance of ewes and on tissue mineral composition of ewes and day-old lambs
SO: Can-J-Anim-Sci, Mar 1978, 58 (1): 35-41. Ref.
CN: DNAL 41.8-C163
Record 8 of 117 in AGRICOLA (1970 - 1978)
AN: CAIN 769015935
TI: 54Mn [manganese isotope] uptake by the ovaries and reproductive tract of cycling and anestrous ewes
SO: Can-J-Physiol-Pharmacol, Oct 1975, 53 (5): 969-972. Ref.
CN: DNAL 444.8-C16
Record 9 of 117 in AGRICOLA (1970 - 1978)
AN: CAIN 729072052
TI: Reproductive responses to supplemental zinc and manganese in grazing Dorset Horn ewes
SO: Australian-J-Exp-Agr-Anim-Husb, Apr 1972, 12 (55): 131-135. Ref.
CN: DNAL 23-AU792
Record 10 of 117 in AGRICOLA (1984 - 12/91)
AN: IND 91041759
AU: Corah,-L.R.; Ives,-S.
TI: The effects of essential trace minerals on reproduction in beef cattle.
SO: Vet-Clin-North-Am-Food-Anim-Pract. Philadelphia, Pa. : W.B. Saunders Company. Mar 1991. v. 7 (1) p. 41-57.
CN: DNAL SF601.V535
IS: ISSN: 0749-0720
DE: beef-cattle. minor-elements. copper-. cobalt-. iodine-. selenium-. zinc-. manganese-. bioavailability-. trace-element-deficiencies. reproductive-disorders. literature-reviews.
Record 11 of 117 in AGRICOLA (1984 - 12/91)
AN: IND 86066067
AU: DiCostanzo,-A.; Meiske,-J.C.; Plegge,-S.D.; Haggard,-D.L.; Chaloner,-K.M.
TI: Influence of manganese, copper and zinc on reproductive performance of beef cows.
SO: Nutr-Rep-Int. Los Altos, Calif. : Geron-X, Inc. Aug 1986. v. 34 (2) p. 287-293.
CN: DNAL RC620.A1N8
IS: ISSN: 0029-6635
DE: beef-cows. diet-. manganese-. copper-. zinc-. reproductive-performance.
Record 12 of 117 in AGRICOLA (1984 - 12/91)
AN: IND 86039214
AU: Brown,-M.A.; Casillas,-E.R.
TI: Manganese and manganese-ATP interactions with bovine sperm adenylate cyclase.
SO: Arch-Biochem-Biophys. New York, N.Y. : Academic Press. Feb 1, 1986. v. 244 (2) p. 719-726. ill.
CN: DNAL 381-AR2
IS: ISSN: 0003-9861
DE: cattle-. spermatozoa-. adenylate-cyclase. manganese-. atp-. interactions-. stimulation-.
Record 13 of 117 in SilverPlatter MEDLINE(R) (2001/01-2001/10)
TI: Analysis of Mn(2+)/Ca(2+) influx and release during Ca(2+) oscillations in mouse eggs injected with sperm extract.
AU: Mohri,-T; Shirakawa,-H; Oda,-S; Sato,-M-S; Mikoshiba,-K; Miyazaki,-S
SO: Cell-Calcium. 2001 May; 29(5): 311-25
AB: Repetitive Ca(2+) release from the endoplasmic reticulum (ER) is necessary for activation of mammalian eggs. Influx and release of Mn(2+) and Ca(2+) during Ca(2+) oscillations induced by injection of sperm extract (SE) into mouse eggs were investigated by Mn(2+)-quenching of intracellular Fura-2 after adding Mn(2+) to external medium. Mn(2+)/Ca(2+) influx was detected at the resting state. A marked Mn(2+)/Ca(2+) influx occurred during the first Ca(2+) release upon SE injection, and persistently facilitated Mn(2+)/Ca(2+) influx was observed during steady Ca(2+) oscillations. As intracellular Mn(2+) concentration ([Mn(2+)](i)) increased progressively, periodic [Mn(2+)](i) rises appeared, corresponding to each Ca(2+)transient but taking a slower time course. A numerical simulation based on continuous Mn(2+)/Ca(2+) influx-extrusion across the plasma membrane and release-uptake across the ER membrane in a competitive manner mimicked well the Mn(2+) oscillations calculated from experimental data, strongly suggesting that repetitive Mn(2+) release develops after Mn(2+) entry and uptake into the ER. In other experiments, a marked Mn(2+) influx occurred upon Mn(2+) addition to Ca(2+)-free medium after depletion of the ER using an ER Ca(2+) pump inhibitor plus repeated injection of inositol 1,4,5-trisphosphate (InsP(3)). No significant increase in Mn(2+) influx was induced by injection of SE, InsP(3), or Ca(2+), when Ca(2+) release was prevented by pre-injection of an antibody against the InsP(3) receptor. We concluded that Ca(2+) influx is activated during the initial large Ca(2+)release possibly by a capacitative mechanism and kept facilitated during steady Ca(2+) oscillations. The finding that repetitive Mn(2+) release is caused by continuous Mn(2+) entry suggests that continuous Ca(2+) influx may play a critical role in refilling the ER and, thereby, maintaining Ca(2+)oscillations in mammalian fertilization. Copyright 2001 Harcourt Publishers Ltd.
Record 14 of 117 in SilverPlatter MEDLINE(R) (2001/01-2001/10)
TI: Inductively coupled plasma emission spectroscopic and flame photometric analysis of goat epididymal fluid.
AU: Gaur,-M; Pruthi,-V; Prasad,-R; Pereira,-B-M
SO: Asian-J-Androl. 2000 Dec; 2(4): 288-92
AB: AIM: The elemental composition of the epididymal luminal fluid (ELF) in adult goat (Capra indica) was investigated. METHODS: ELF was collected by micropuncture from twelve sites along the epididymal duct. The elemental contents was analyzed with inductively coupled plasma (ICP) emission spectroscopy, a microanalytical technique that can simultaneously measure many elements in minute volumes of sample. The Na and K concentrations were determined by flame photometry. RESULTS: ICP spectroscopy showed the presence of copper, calcium, nickel, iron, magnesium, chromium, titanium and zinc in ELF, with fluctuating levels at different sites along the length of the epididymis. Cadmium, cobalt, lead and manganese were not found. The Na+/K+ ratio was seen to be higher at the initial segments of the epididymis and lower at the distal. CONCLUSION: It is proposed that the observed characteristic distribution of elements in ELF may have far reaching implications in sperm maturation and storage known to occur in the epididymis.
Record 15 of 117 in SilverPlatter MEDLINE(R) (2001/01-2001/10)
TI: In vitro effects of metal ions (Fe2+, Mn2+, Pb2+) on sperm motility and lipid peroxidation in human semen.
AU: Huang,-Y-L; Tseng,-W-C; Lin,-T-H
SO: J-Toxicol-Environ-Health-A. 2001 Feb 23; 62(4): 259-67
AB: The effects of divalent manganese ion (Mn2+), ferrous iron (Fe2+), and lead ion (Pb2+) on human sperm motility and lipid peroxidation were examined. Human semen from healthy male volunteers was incubated with 0, 5, 50, or 500 ppm divalent metal ions, and the sperm motility was determined at 0, 2, 4, 6, or 8 h by microscopy. Malondialdehyde (MDA) levels in seminal plasma was measured by high-performance liquid chromatography after 8 h of exposure. The results showed that 500 ppm Mn2+ or Pb2+ significantly inhibited sperm motility without an accompanying change in seminal MDA levels. Incubation with Fe2+ significantly inhibited sperm motility at 5 ppm, associated with a marked rise in MDA levels. Our results suggested that Fe2+ may induce lipid peroxidation to inhibit sperm motility. In the case of Mn2+ and Pb2+ there is an absence of seminal lipid peroxidation and the observed inhibition of sperm motility at high concentrations is not biologically or environmentally relevant.
Record 16 of 117 in SilverPlatter MEDLINE(R) (2001/01-2001/10)
TI: Effects of long-term exposure to manganese chloride on fertility of male and female mice.
AU: Elbetieha,-A; Bataineh,-H; Darmani,-H; Al-Hamood,-M-H
SO: Toxicol-Lett. 2001 Mar 8; 119(3): 193-201
AB: The effect of long-term ingestion of manganese (II) chloride tetrahydrate was investigated on fertility of male and female Swiss mice. Adult male or female mice ingested a solution of manganese chloride along with drinking water at concentrations of 1000, 2000, 4000 and 8000 mg/l for 12 weeks. Fertility was significantly reduced in male mice exposed to manganese chloride solution at a concentration of 8000 mg/l, but not at the other concentrations. There were no treatment-related effects on the number of implantation sites, viable fetuses or the number of resorptions in female rats impregnated by males who had ingested manganese chloride. Fertility was not significantly reduced in female mice exposed to manganese chloride solution at all concentrations used in this study. However, the numbers of implantations and viable fetuses were significantly reduced in females exposed to manganese chloride solution at a concentration of 8000 mg/l. There was no significant effect on the number of resorbed fetuses in females exposed to manganese chloride solution compared to their control counterparts. Absolute body weight was not significantly affected in females exposed to manganese chloride solutions. However, ovarian weight was significantly increased in females exposed to manganese chloride solution at concentrations of 4000 and 8000 mg/l. A significant increase in the uterine weight was also observed at all concentrations used in the study. These results indicate that ingestion of manganese chloride by adult male and female mice causes some adverse effects on fertility and reproduction.
Record 17 of 117 in SilverPlatter MEDLINE(R) (2001/01-2001/10)
TI: DNA condensation in two dimensions.
AU: Koltover,-I; Wagner,-K; Safinya,-C-R
SO: Proc-Natl-Acad-Sci-U-S-A. 2000 Dec 19; 97(26): 14046-51
AB: We have found that divalent electrolyte counterions common in biological cells (Ca(2+), Mg(2+), and Mn(2+) ) can condense anionic DNA molecules confined to two-dimensional cationic surfaces. DNA-condensing agents in vivo include cationic histones and polyamines spermidine and spermine with sufficiently high valence (Z) 3 or larger. In vitro studies show that electrostatic forces between DNA chains in bulk aqueous solution containing divalent counterions remain purely repulsive, and DNA condensation requires counterion valence Z >/= 3. In striking contrast to bulk behavior, synchrotron x-ray diffraction and optical absorption experiments show that above a critical divalent counterion concentration the electrostatic forces between DNA chains adsorbed on surfaces of cationic membranes reverse from repulsive to attractive and lead to a chain collapse transition into a condensed phase of DNA tethered by divalent counterions. This demonstrates the importance of spatial dimensionality to intermolecular interactions where nonspecific counterion-induced electrostatic attractions between the like-charged polyelectrolytes overwhelm the electrostatic repulsions on a surface for Z = 2. This new phase, with a one-dimensional counterion liquid trapped between DNA chains at a density of 0.63 counterions per DNA bp, represents the most compact state of DNA on a surface in vitro and suggests applications in high-density storage of genetic information and organo-metallic materials processing.
Record 18 of 117 in SilverPlatter MEDLINE(R) (2001/01-2001/10)
TI: RGD-independent binding of integrin alpha9beta1 to the ADAM-12 and -15 disintegrin domains mediates cell-cell interaction.
AU: Eto,-K; Puzon-McLaughlin,-W; Sheppard,-D; Sehara-Fujisawa,-A; Zhang,-X-P; Takada,-Y
SO: J-Biol-Chem. 2000 Nov 10; 275(45): 34922-30
AB: ADAMs (a disintegrin and metalloproteases) mediate several important processes (e.g. tumor necrosis factor-alpha release, fertilization, and myoblast fusion). The ADAM disintegrin domains generally lack RGD motifs, and their receptors are virtually unknown. Here we show that integrin alpha(9)beta(1) specifically interacts with the recombinant ADAMs-12 and -15 disintegrin domains in an RGD-independent manner. We also show that interaction between ADAM-12 or -15 and alpha(9)beta(1) supports cell-cell interaction. Interestingly, the cation requirement and integrin activation status required for alpha(9)beta(1)/ADAM-mediated cell adhesion and cell-cell interaction is similar to those required for known integrin-extracellular matrix interaction. These results are quite different from recent reports that ADAM-2/alpha(6)beta(1) interaction during sperm/egg fusion requires an integrin activation status distinct from that for extracellular matrix interaction. These results suggest that alpha(9)beta(1) may be a major receptor for ADAMs that lack RGD motifs, and that, considering a wide distribution of ADAMs and alpha(9)beta(1), this interaction may be of potential biological and pathological significance.
CN: GM47175GMNIGMS; GM49899GMNIGMS
Record 19 of 117 in MEDLINE(R)+ (1998-2000)
TI: Rescue of the corpus luteum and an increase in luteal superoxide dismutase expression induced by placental luteotropins in the rat: action of testosterone without conversion to estrogen.
AU: Takiguchi,-S; Sugino,-N; Kashida,-S; Yamagata,-Y; Nakamura,-Y; Kato,-H
SO: Biol-Reprod. 2000 Feb; 62(2): 398-403
AB: The superoxide radical and its scavenger, superoxide dismutase (SOD), play important roles in the regulation of corpus luteum function. The present study was undertaken to investigate whether SOD is related to pregnancy-induced maintenance of corpus luteum function. Placentae obtained from rats on Day 12 of pregnancy were incubated for 24 h, and the supernatant was used as placental luteotropins. Pseudopregnant rats were given the placental incubation medium from Day 9 to Day 12 of pseudopregnancy. The treatment significantly increased serum progesterone concentrations on Day 12 of pseudopregnancy. Both activities and mRNA levels of copper-zinc SOD (Cu,Zn-SOD) and manganese SOD (Mn-SOD) in the corpus luteum were also increased on Day 12 of pseudopregnancy. Treating the placental incubation medium with charcoal significantly eliminated the stimulatory effects of placental incubation medium on serum progesterone concentrations and luteal Mn-SOD expression, but not on Cu,Zn-SOD expression. The inhibitory effect of the charcoal treatment on luteal Mn-SOD expression was reversed by supplementation with testosterone or dihydrotestosterone (DHT), but serum progesterone concentrations were recovered only by DHT. Testosterone or DHT alone had no effect on serum progesterone concentrations and luteal SOD expression. In conclusion, placental luteotropins increased SOD expression in the corpus luteum and stimulated progesterone production, suggesting that SOD is involved in the maintenance of the corpus luteum function by placental luteotropins. In addition, androgen, with other placental luteotropins, acted to stimulate progesterone production and Mn-SOD expression in pseudopregnant rats.
Record 20 of 117 in MEDLINE(R)+ (1998-2000)
TI: Superoxide dismutase expression in the human corpus luteum during the menstrual cycle and in early pregnancy.
AU: Sugino,-N; Takiguchi,-S; Kashida,-S; Karube,-A; Nakamura,-Y; Kato,-H
SO: Mol-Hum-Reprod. 2000 Jan; 6(1): 19-25
AB: To investigate the possible role of the superoxide radical and its scavenging system in the human corpus luteum, superoxide dismutase (SOD) values and lipid peroxide concentrations were analysed in the corpora lutea during the menstrual cycle and in early pregnancy. Copper-zinc SOD (Cu,Zn-SOD) activities increased from the early to mid-luteal phase, and gradually decreased thereafter and were the lowest in the regression phase. In pregnant corpus luteum, Cu,Zn-SOD activities were significantly higher than those in the mid-luteal phase. In contrast, manganese SOD (Mn-SOD) activities were low in the mid-luteal phase and increased toward the regression phase. Changes in mRNA expression of both types of SOD were similar to changes in their activities. Lipid peroxide concentrations were the highest in the regression phase whereas they were remarkably low in pregnant corpus luteum. The effects of human chorionic gonadotrophin (HCG) on luteal SOD were studied in vitro. HCG significantly increased Cu,Zn-SOD expression in mid-luteal phase corpora lutea, but not in late luteal phase corpora lutea. In conclusion, the present study suggests that the superoxide radical and its scavenging system, especially Cu,Zn-SOD, play important roles in the regulation of human luteal function. The stimulation of luteal Cu, Zn-SOD expression by HCG may be important in maintaining luteal cell integrity when pregnancy occurs.
Record 21 of 117 in MEDLINE(R)+ (1998-2000)
TI: Metals and metalloids in tissues of American alligators in three Florida lakes.
AU: Burger,-J; Gochfeld,-M; Rooney,-A-A; Orlando,-E-F; Woodward,-A-R; Guillette,-L-J
SO: Arch-Environ-Contam-Toxicol. 2000 May; 38(4): 501-8
AB: Concentrations of metals and selenium were examined in tissues of American alligators (Alligator mississippiensis) from three lakes in central Florida, in one of which alligators have exhibited reproductive or developmental defects. Our overall objective was to determine whether the levels of metals were sufficiently high to confound the association between chlorinated hydrocarbons, which are elevated in eggs and juvenile plasma, and reproductive impairment. The concentrations of all metals were relatively low compared to those reported for alligators from elsewhere in Florida and the southeastern United States, suggesting that reproductive impairment is not due to metals and that metals pose no health risk to the alligators. We also wanted to determine whether skin, biopsied tail muscle, or tail tip tissue, all easily collected from live alligators, could be used as surrogate measures of internal tissue loads. Concentrations of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in liver were highly correlated with at least one of the three biopsied tissues. Only tin showed no significant positive correlation. No single tissue gave a high prediction of liver levels for all metals, although skin gave the highest correlation for mercury, and tail muscle gave the best overall correlation for lead and cadmium.
Record 22 of 117 in MEDLINE(R)+ (1998-2000)
TI: Effects on bone loss of manganese alone or with copper supplement in ovariectomized rats. A morphometric and densitomeric study.
AU: Rico,-H; Gomez-Raso,-N; Revilla,-M; Hernandez,-E-R; Seco,-C; Paez,-E; Crespo,-E
SO: Eur-J-Obstet-Gynecol-Reprod-Biol. 2000 May; 90(1): 97-101
AB: OBJECTIVE: The aim of this study was to examine the effect of manganese (Mn) alone and with the addition of copper (Cu) in the inhibition of osteopenia induced by ovariectomy (OVX) in rats. STUDY CONDITIONS: Four lots of 100-day-old female Wistar rats were divided into experimental groups of 15 each. One group received a diet supplemented with 40 mg/kg of Mn per kilogram of feed (OVX+Mn). The second group received the same diet as the first, but with an additional 15 mg/kg of copper (OVX+Mn+Cu). The third group of 15 OVX and the fourth group of 15 Sham-OVX received no supplements. At the conclusion of the 30-day experiment, the rats were slaughtered and their femurs and fifth lumbar vertebrae were dissected. Femoral and vertebral length were measured with caliper and bones were weighed on a precision balance. The bone mineral content (BMC) and bone density (BMD) of the femur (F-BMC, mg and F-BMD, mg/cm(2)) and the fifth lumbar vertebra (V-BMC, mg and V-BMD, mg/cm(2)) were measured separately with dual energy X-ray absorptiometry. RESULTS: The F-BMD, mg/cm(2) was lower in the OVX than in the Sham-OVX group (P<0.0001) and in the other two groups receiving mineral supplements (P<0.005 in both). F-BMC, mg was significantly lower in the OVX group than in the other three (P<0.0001 in all cases). Calculations for V-BMC, mg and V-BMD, mg/cm(2) are similar to findings in the femur. CONCLUSIONS: These data show that a Mn supplement is an effective inhibitor of loss of bone mass after OVX, both on the axial and the peripheral levels, although this effect is not enhanced with the addition of Cu.
Record 23 of 117 in MEDLINE(R)+ (1998-2000)
TI: Ca(2+) entry through store-operated channels in mouse sperm is initiated by egg ZP3 and drives the acrosome reaction.
AU: O'Toole,-C-M; Arnoult,-C; Darszon,-A; Steinhardt,-R-A; Florman,-H-M
SO: Mol-Biol-Cell. 2000 May; 11(5): 1571-84
AB: Fertilization occurs after the completion of the sperm acrosome reaction, a secretory event that is triggered during gamete adhesion. ZP3, an egg zona pellucida glycoprotein, produces a sustained increase of the internal Ca(2+) concentration in mouse sperm, leading to acrosome reactions. Here we show that the sustained Ca(2+) concentration increase is due to the persistent activation of a Ca(2+) influx mechanism during the late stages of ZP3 signal transduction. These cells also possess a Ca(2+) store depletion-activated Ca(2+) entry pathway that is open after treatment with thapsigargin. Thapsigargin and ZP3 activate the same Ca(2+) permeation mechanism, as demonstrated by fluorescence quenching experiments and by channel antagonists. These studies show that ZP3 generates a sustained Ca(2+) influx through a store depletion-operated pathway and that this drives the exocytotic acrosome reaction.
CN: AR44066ARNIAMS; GM56479GMNIGMS; HD32177HDNICHD
Record 24 of 117 in MEDLINE(R)+ (1998-2000)
TI: Maternal trace elements, vitamin B12, vitamin A, folic acid, and fetal malformations.
AU: Stoll,-C; Dott,-B; Alembik,-Y; Koehl,-C
SO: Reprod-Toxicol. 1999 Jan-Feb; 13(1): 53-7
AB: The demonstrated teratogenicity of maternal zinc deficiency in rats has led to burgeoning interest in zinc and other trace elements as important factors in embryonic development. Levels of zinc, copper, manganese, magnesium, folic acid, vitamin B12 and vitamin A were evaluated at the beginning of pregnancy in the plasma of pregnant women who later delivered a malformed newborn. Fetal chromosomal anomalies and recognizable nonchromosomal syndromes were excluded. The results were compared to control women who delivered normal babies. One hundred seventy mothers had malformed children. The more frequent congenital malformations were congenital heart diseases (72 cases including 24 VSD), musculoskeletal malformations (21 cases), urogenital malformations (23 cases), spina bifida (6 cases), hydrocephaly (6 cases), and labial cleft (14 cases). Maternal plasma concentrations of zinc, copper, magnesium, manganese, folate, vitamin B12, and vitamin A of malformed children did not differ from controls. Thus vitamin profiles do not form a suitable means for identifying women at risk for having a child with congenital malformations.
Record 25 of 117 in MEDLINE(R)+ (1998-2000)
TI: Effect of additional cobalt, copper, manganese, and zinc on reproduction and milk yield of lactating dairy cows receiving bovine somatotropin.
AU: Campbell,-M-H; Miller,-J-K; Schrick,-F-N
SO: J-Dairy-Sci. 1999 May; 82(5): 1019-25
AB: The objective of this study was to determine whether organically complexed Co, Cu, Mn, and Zn would improve the reproductive performance and milk and milk component production in lactating dairy cows that began receiving bovine somatotropin in the ninth week of lactation. Holstein (n = 50) and Jersey (n = 10) cows were blocked by breed, lactation number, and incidence of retained fetal membranes. Two diets assigned within blocks and fed from parturition until 154 d of lactation were control or control supplemented daily with 26 mg of Co as Co glucoheptonate, 125 mg of Cu as Cu-Lys, 199 mg of Mn as Mn-Met, and 359 mg of Zn as Zn-Met. Cows were fitted with electronic pressure-sensing devices in the second week of lactation for detection of estrus. Ovarian structures were determined via transrectal ultrasonography at 7-d intervals from parturition until observation of the first corpus luteum. Blood samples were taken at 7-d intervals and analyzed for plasma concentrations of progesterone, insulin, and urea nitrogen. Onset of luteal activity was identified by progesterone concentrations > or = 1 ng/ml. Retained fetal membranes increased days to first estrus (detected via electronic estrous detection), first luteal activity, and first corpus luteum in control cows but not in supplemented cows. Days to first observed estrus were greater for control cows than for supplemented cows. Days to first service, days open, days from first service to conception, services per conception, milk yield, milk components, and somatic cell counts were similar for control and supplemented cows. Supplementation with complexed trace minerals effectively reduced days to first estrus.
Record 26 of 117 in MEDLINE(R)+ (1998-2000)
TI: Effects of supplementation of organic and inorganic combinations of copper, cobalt, manganese, and zinc above nutrient requirement levels on postpartum two-year-old cows.
AU: Olson,-P-A; Brink,-D-R; Hickok,-D-T; Carlson,-M-P; Schneider,-N-R; Deutscher,-G-H; Adams,-D-C; Colburn,-D-J; Johnson,-A-B
SO: J-Anim-Sci. 1999 Mar; 77(3): 522-32
AB: The objective of this study was to determine whether a combination of Cu, Co, Mn, and Zn in an organic or inorganic form fed at higher than nutrient recommendations for 2-yr-old cows from calving to breeding would affect pregnancy rate, calving date, calf performance, and cow liver and serum mineral concentrations. Crossbred 2-yr-old cows were used after calving in 1994 (n = 127) and 1995 (n = 109). Cows were blocked by calving date to one of three treatments: 1) no supplemental minerals (CTL), 2) organic minerals (ORG), or 3) inorganic minerals (ING). Minerals were fed for the same daily intake for both organic and inorganic treatments: Cu (125 mg), Co (25 mg), Mn (200 mg), and Zn (360 mg). Cows were individually fed a mineral-protein supplement with grass hay from calving (February-March) to before breeding (May 15). Hay intakes were calculated using chromium oxide boluses to determine fecal output. Fecal excretion of minerals was calculated following trace element analysis of feces. Liver biopsies were obtained before calving, after calving (start of supplementation), at the end of supplementation, and in midsummer. Over 2 yr, more cows did not become pregnant (P < .01) in ORG (11/78) and ING (11/78) treatments than in CTL (0/80) treatments. A treatment x year interaction was found for day of conception. Cows in the ORG group conceived later (P < .01) than cows in the ING or CTL groups in 1994. In 1995, there was no difference (P > .10) in day of conception among groups. Liver Zn and Mn concentrations were not different (P > .10) and Cu concentrations increased (P < .01) for the ORG and ING groups. Cows in the ORG and ING groups had higher (P < .01) concentrations of Cu, Mn, and Zn in the feces than the CTL cows. Trace elements in the feces did not differ for ORG and ING groups. Results indicate that combinations of Cu, Co, Mn, and Zn fed at higher levels than are required reduced reproductive performance.
Record 27 of 117 in MEDLINE(R)+ (1998-2000)
TI: Nutrition versus toxicology of manganese in humans: evaluation of potential biomarkers.
SO: Neurotoxicology. 1999 Apr-Jun; 20(2-3): 205-12
AB: Manganese intake can vary greatly with food choices, water composition, and supplement use. Thus, individuals consuming Western diets consume from < 1 to > 10 mg Mn/d. The levels of manganese intake associated with adverse effects (both deficient and toxic) are debatable. Moreover, many of the symptoms of manganese deficiency (growth retardation, changes in circulating HDL cholesterol and glucose levels, reproductive failure) and manganese toxicity (growth depression, anemia) are non-specific. The bone deformities observed in manganese-deficient animals and neurological symptoms of individuals who have inhaled excess manganese are permanent and illustrate the need to identify sensitive biomarkers of manganese status that appear before these symptoms. Manganese balance and excretion data are not useful biomarkers of manganese exposure but demonstrate that the body is protected against manganese toxicity primarily by low absorption and/or rapid presystemic elimination of manganese by the liver. Serum manganese concentrations in combination with lymphocyte manganese-dependent superoxide dismutase (MnSOD) activity and perhaps blood arginase activity, appear to be the best ways to monitor ingestion of insufficient manganese. Serum manganese concentrations in combination with brain MRI (magnetic resonance imaging) scans, and perhaps a battery of neurofunctional tests, appear to be the best ways to monitor excessive exposure to manganese.
Record 28 of 117 in MEDLINE(R)+ (1998-2000)
TI: Protein phosphatase activity in the rat ovary throughout pregnancy and pseudopregnancy.
AU: Eyster,-K-M; Berger,-T-L; Rodrigo,-M-C; Sheth,-M-V
SO: Biol-Reprod. 1998 Feb; 58(2): 338-45
AB: Specific protein phosphatase activity against protein kinase C-phosphorylated substrate was measured in the rat ovary during pseudopregnancy and pregnancy. Tissues were processed in the presence of sodium fluoride and inorganic phosphate to inhibit the phosphatase and thereby prevent autodephosphorylation of the type 2A protein phosphatase (PP2A) during homogenization. Manganese was added at the time of enzyme assay to reactivate the phosphatase. The specific activity of the protein phosphatase did not vary significantly across pseudopregnancy (p > 0.05). In contrast, the specific activity of protein phosphatase decreased significantly between Day 7 and Day 10 of pregnancy (28.8 +/- 5 pmol/min x microg protein and 20.7 +/- 2 pmol/min x microg protein, respectively; p < 0.05) and remained at the decreased value for the remainder of pregnancy. To determine whether hormones of pregnancy could regulate PP2A activity in the ovaries, pseudopregnant rats were treated with prolactin (3 IU twice a day), bromocriptine (100 microg twice a day), or estradiol benzoate (50 microg). Bromocriptine and estradiol treatments caused a decrease in PP2A-specific activity, but prolactin had no effect. Bromocriptine treatment caused a decrease in the protein content of the PP2A catalytic subunit, but prolactin and estradiol treatments had no effect. The data suggest that the specific activity and protein content of PP2A in the rat ovary are hormonally regulated.
Record 29 of 117 in MEDLINE(R)+ (1998-2000)
TI: Acrosome reaction inactivation in sea urchin sperm.
AU: Guerrero,-A; Garcia,-L; Zapata,-O; Rodriguez,-E; Darszon,-A
SO: Biochim-Biophys-Acta. 1998 Mar 5; 1401(3): 329-38
AB: Acrosome reaction inactivation (ARI) is a process that renders sperm irreversibly refractory to the egg jelly (the natural inducer of the acrosome reaction, AR). This process triggered by the egg jelly, is associated with an increase in [Ca2+]i. However, we show here that a rise in [Ca2+]i alone is not sufficient to induce ARI, since artificially increasing [Ca2+]i with either an ionophore or rising external pH, does not trigger ARI. Contrary to the AR which strictly requires Ca2+, ARI can be triggered almost equally well by Sr2+. On the other hand, Mn2+ inhibits ARI and, as we showed earlier, does not affect AR. These observations indicate that the mechanisms involved in ARI differ from those leading to AR. In addition, we report here that high external pH (a non-physiological inducer of AR) triggers the AR in previously inactivated sperm by opening the same Ca2+ channels activated by the egg jelly. Considering that the opening of Ca2+ channels is one of the earliest responses triggered by the egg jelly and that ARI requires the egg jelly receptor to be activated, we have concluded that ARI involves the uncoupling between the egg jelly receptor and Ca2+ channels. Furthermore, intracellular pH (pHi) determinations, in the presence or absence of ionomycin to substitute for the uncoupled Ca2+ channels, indicate that pHi regulation is also impaired in inactivated sperm. In conclusion, ARI is a manifestation of the uncoupling of the egg jelly receptor from the different ion transport systems required for the acrosome reaction.
Record 30 of 117 in MEDLINE(R)+ (1998-2000)
TI: Calcium elevation in sheep cumulus-oocyte complexes after luteinising hormone stimulation.
AU: Mattioli,-M; Gioia,-L; Barboni,-B
SO: Mol-Reprod-Dev. 1998 Jul; 50(3): 361-9
AB: We investigated Ca2+ levels in intact cumulus-oocyte complexes (COCs) on exposure to peak levels of luteinising hormone (LH). Specific preparations were used where cumulus corona cells were loaded with a membrane-permeant Ca(2+)-sensitive dye (FLUO-3AM), whereas the oocyte was injected directly with the nonpermeant form of the dye (FLUO-3). After exposure to LH, cumulus and corona radiata cells showed distinct rises in intracellular Ca2+ in 50-200 sec. The pattern of Ca2+ response varied in the different cells both for the duration of the transients and for their persistence. Interestingly, Ca2+ elevations were recorded in all the layers of the cumulus mass, including the innermost layer of corona cells, demonstrating the wide diffusion of LH receptors. Following the Ca2+ raise in somatic cells, an intracellular Ca2+ elevation also was recorded within the oocyte with a delay of 100-300 sec. The elevation started at the cortex of the oocyte and then spread all over the ooplasm. The addition of verapamil or manganese chloride did not prevent LH-induced Ca2+ elevation in the COC, whereas mechanical uncoupling of cumulus cells from the oocyte prevented any Ca2+ response within the oocyte. The results indicate that cumulus corona cells are capable of transducing LH message by rising intracellular Ca2+ and show that this signal is rapidly transferred into the oocyte through gap junctions. This may result from the direct diffusion of Ca2+ or its putative releaser IP3 from cumulus cells to the oocyte.
Record 31 of 117 in MEDLINE(R)+ (1998-2000)
TI: Differential regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase in the rat corpus luteum: induction of manganese superoxide dismutase messenger ribonucleic acid by inflammatory cytokines.
AU: Sugino,-N; Telleria,-C-M; Gibori,-G
SO: Biol-Reprod. 1998 Jul; 59(1): 208-15
AB: This study was undertaken to investigate the regulation of mitochondrial manganese superoxide dismutase (Mn-SOD) and cytosolic copper-zinc SOD (Cu,Zn-SOD) in the corpus luteum by inflammatory cytokines. We first examined the developmental expression of both SOD mRNAs in the rat corpus luteum throughout pregnancy. SOD mRNA levels were determined by semiquantitative reverse transcription-polymerase chain reaction. Whereas Cu,Zn-SOD mRNA levels decreased during late pregnancy, Mn-SOD mRNA levels remained elevated. We secondly examined the effects of inflammatory reaction on luteal SODs. Rats received injections of lipopolysaccharide (LPS; 5 mg, i.p.) on Day 15 of pregnancy, and corpora lutea were removed 2 h later. LPS caused an increase in Mn-SOD mRNA levels in the corpus luteum and a decrease in serum progesterone levels, but neither in levels of Cu,Zn-SOD mRNA. To further study the effects of LPS or LPS-induced cytokines, we incubated either whole corpora lutea obtained on Day 15 of pregnancy or a temperature-sensitive simian virus-40 transformed luteal cell line (GG-CL; derived from large luteal cells of the corpus luteum of pregnant rats) in serum-free medium with LPS, interleukin-1alpha (IL-1alpha), IL-beta, IL-6, and tumor necrosis factor alpha. LPS and these cytokines induced a remarkable increase in Mn-SOD mRNA levels in both corpora lutea and GG-CL cells but had no effect on Cu,Zn-SOD mRNA expression. In conclusion, Cu,Zn-SOD and Mn-SOD mRNAs are differently expressed and regulated in the corpus luteum of pregnancy. Mn-SOD mRNA, but not Cu,Zn-SOD mRNA, is highly induced by inflammatory cytokines and may play an important role in protecting luteal cells from inflammation-mediated oxidative damage.
CN: FIC1F05TW05241TWFIC; HD11119HDNICHD; HD11119HDNICHD
Record 32 of 117 in MEDLINE(R)+ (1998-2000)
TI: Ovarian function in superoxide dismutase 1 and 2 knockout mice.
AU: Matzuk,-M-M; Dionne,-L; Guo,-Q; Kumar,-T-R; Lebovitz,-R-M
SO: Endocrinology. 1998 Sep; 139(9): 4008-11
AB: Copper/zinc superoxide dismutase (SOD1) and manganese superoxide dismutase (SOD2) are the two major intracellular enzymes which inactivate superoxide radicals. SOD1 is present in both cytoplasmic and nuclear compartments whereas SOD2 is localized to mitochondria. Both enzymes are expressed in multiple tissues as well as ovaries of several species including humans and rodents. Dominant mutations in SOD1 are associated with amyotrophic lateral sclerosis. We have previously demonstrated that SOD2-deficient mice die within three weeks of birth due to oxidative mitochondrial injury in central nervous system neurons and cardiac myocytes. In this report, we demonstrate that female homozygous mutant mice lacking SOD1 can survive to the adult stage but are subfertile. Whereas breeding of 5 SOD1 heterozygote females produced an average of 1.0 litter/month with 8.6 offspring/litter (n = 31 litters), only 11 of 16 SOD1 homozygote mice over a 2-6 month period became pregnant averaging 0.23 litters/month with an average litter size of 2.7 (n = 21 litters). Histological analysis of the ovaries from SOD1-deficient mice often reveals many primary and small antral follicles but few corpora lutea. In addition, ovaries from postnatal SOD2-deficient mice, transplanted to the bursa of wild-type hosts, show all stages of folliculogenesis including corpora lutea and can give rise to viable offspring. These studies support an important role of SOD1 in female reproductive function and suggest that SOD2 is not essential for ovarian function.
Record 33 of 117 in MEDLINE(R)+ (1998-2000)
TI: Hormonal regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase messenger ribonucleic acid in the rat corpus luteum: induction by prolactin and placental lactogens.
AU: Sugino,-N; Hirosawa-Takamori,-M; Zhong,-L; Telleria,-C-M; Shiota,-K; Gibori,-G
SO: Biol-Reprod. 1998 Sep; 59(3): 599-605
AB: The corpus luteum expresses two enzymes that scavenge superoxide radicals and protect the cells from their toxic activities: cytosolic copper, zinc-superoxide dismutase (Cu,Zn-SOD) and mitochondrial manganese-SOD (Mn-SOD). The present study was undertaken to investigate whether the mRNA expression of each of these enzymes is regulated by luteotropic hormones. Cu,Zn-SOD and Mn-SOD mRNA levels were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). We first examined the effects of prolactin (PRL) on Cu,Zn-SOD and Mn-SOD mRNA expression in the corpus luteum. Hypophysectomy of Day 3 pregnant rats caused a sharp decline in both Cu,Zn-SOD and Mn-SOD mRNA levels, which was completely reversed by PRL administration. To further examine the effects of PRL and rat placental lactogen (rPL) on the expression of these enzymes, either primary luteinized granulosa cells or temperature-sensitive simian virus-40 transformed luteal cells (GG-CL) were cultured with different doses of PRL or rPL. These hormones induced a remarkable increase in Cu,Zn-SOD and Mn-SOD mRNA levels in both primary luteinized granulosa cells and GG-CL cells. Interestingly, whereas PRL up-regulated the expression of the SOD in luteal cells, other luteotropic hormones such as estradiol and dexamethasone inhibited both SOD mRNA expression while progesterone had no effect. In conclusion, PRL and PRL-like hormones induce a protective ability against toxic oxygen radicals by stimulating the expression of SODs, a phenomenon that may play an important role in maintaining luteal cell integrity and steroidogenic capacity.
Record 34 of 117 in MEDLINE(R)+ (1998-2000)
TI: Paternal alcohol exposure: developmental and behavioral effects on the offspring of rats.
AU: Ledig,-M; Misslin,-R; Vogel,-E; Holownia,-A; Copin,-J-C; Tholey,-G
SO: Neuropharmacology. 1998; 37(1): 57-66
AB: The effect of paternal alcohol exposure on neurochemical and behavioral parameters was investigated using as a model system glial cells derived from newborn rat brain and cultured for 4 weeks. The total brain neurochemical parameters from rats born to mothers sired by an alcohol treated father were also investigated. Enzymatic markers of nerve cell development (enolase isoenzymes and glutamine synthetase) and the defense system (superoxide dismutase) against free radicals formed during alcohol degradation were measured in order to evaluate nerve cell damage. Behavioral locomotor tests (open-field, novelty-seeking, light/dark) were carried out to show long-lasting effects of paternal alcoholization on the offspring. Behavioral and developmental alterations were found until 1 year of age in the offspring and a significant growth retardation was observed in the males. Our results suggest that paternal alcohol exposure produces developmental and behavioral effects in the offspring. The consequence of either alcohol withdrawal during stage one spermatogenesis, or maternal diet supplementation with manganese during pregnancy were investigated. It was observed that some of the effects of paternal alcohol exposure on the offspring may be reversed by these treatments.
Record 35 of 117 in MEDLINE(R)+ (1998-2000)
TI: Intracellular Ca2+ homeostasis in rat round spermatids.
AU: Berrios,-J; Osses,-N; Opazo,-C; Arenas,-G; Mercado,-L; Benos,-D-J; Reyes,-J-G
SO: Biol-Cell. 1998 Sep; 90(5): 391-8
AB: Intracellular calcium, [Ca2+]i, can regulate meiotic progression of mammalian oocytes. However, the role of [Ca2+]i in the regulation of the spermatogenic process and its cellular homeostatic mechanisms in spermatogenic cells has not been elucidated. Using intracellular fluorescent probes for Ca2+ and immunodetection of plasma membrane (PM) Ca(2+)-ATPases, we report that: a) rat round spermatids maintain [Ca2+]i levels of 60 +/- 5 nM (SEM), as estimated with fluo-3 in single cells or fura-2 in cells in suspension; b) these cells regulate [Ca2+]i by actively extruding it using a PM Ca(2+)-ATPase; c) rat spermatids also actively transport Ca2+ by sarco-endoplasmic reticulum type ATPases (SERCA); d) rat spermatids possess non-mitochondrial intracellular Ca2+i stores insensitive to thapsigargin but releasable by ionomycin; and e) rat spermatids do not activate Ca2+ entry mechanisms by the release of Ca2+ from SERCA-regulated stores. These results demonstrate that rat round spermatids can generate modulated intracellular Ca2+ signals upon activation of Ca2+ channels or Ca2+ release from intracellular stores.
Record 36 of 117 in MEDLINE(R)+ (1998-2000)
TI: Assessment of aggression, sexual behavior and fertility in adult male rat following long-term ingestion of four industrial metals salts.
AU: Bataineh,-H; Al-Hamood,-M-H; Elbetieha,-A-M
SO: Hum-Exp-Toxicol. 1998 Oct; 17(10): 570-6
AB: 1. The effect of long-term ingestion of the industrial metals salts, manganese sulfate, aluminum chloride, lead acetate and copper chloride was investigated on aggression, sexual behavior and fertility in male rat. Adult male rats ingested solutions of these salts along with drinking water at a concentration of 1000 p.p.m. for 12 weeks. 2. Male rat sexual behavior was suppressed after the ingestion of manganese sulfate, aluminum chloride, lead acetate and copper chloride. The ingestion of solutions of these salts markedly prolonged the intromission and ejaculation latencies. Aluminum chloride and copper chloride reduced the copulatory efficiency. 3. Male rat aggression was also abolished after the ingestion of manganese sulfate, aluminum chloride, lead acetate and copper chloride. The ingestion of solutions of these salts markedly suppressed lateralizations, boxing bouts, fight with stud male and ventral presenting postures. 4. Fertility was reduced in male rats ingested with lead acetate. The total number of resorptions was increased in female rats impregnated by males ingested with manganese sulfate and lead acetate. 5. Body, absolute or relative testes, seminal vesicles weights were dropped in adult male rats ingested with manganese sulfate, aluminum chloride, lead acetate and copper chloride. However, the absolute or relative preputial gland weights were not affected. Collectively, these results suggest that the long-term ingestion of manganese sulfate, aluminum chloride, lead acetate and copper chloride would have adverse effects on sexual behavior, territorial aggression, fertility and the reproductive system of the adult male rat.
Record 37 of 117 in MEDLINE(R)+ (1998-2000)
TI: The influence of dietary sources of zinc, copper and manganese on canine reproductive performance and hair mineral content.
AU: Kuhlman,-G; Rompala,-R-E
SO: J-Nutr. 1998 Dec; 128(12 Suppl): 2603S-2605S
Record 38 of 117 in MEDLINE(R)+ (1998-2000)
TI: Regulation of agonist-receptor binding by G proteins and divalent cations in spermatozoa solubilized A1 adenosine receptors.
AU: Minelli,-A; Allegrucci,-C; Rosati,-R; Mezzasoma,-I
SO: Mol-Genet-Metab. 1998 Mar; 63(3): 183-90
AB: Solubilized A1 adenosine receptor (A1AR) was used to investigate the effect of several cations on agonist-binding characteristics and GTP hydrolysis. It was shown by Western blot with G beta-M14 that this preparation contains both G proteins and receptor. The role of the receptor molecule is to facilitate the activation of G proteins as alpha-GTP complex, and GTP hydrolysis has important consequences for the basic deactivation mechanism. Divalent cations, such as Mn2+, Ca2+, and Mg2+, potentiated the agonist-specific binding: Mn2+ had the highest apparent affinity with half-maximal effect at 50 microM. Binding assays, performed in the presence of 100 microM Mn2+, showed an increase in the apparent affinity of the binding sites, whereas, in the presence of 1 mM Mg2+, significant alteration of the apparent affinity, but not of the number of sites, was detected. Concentrations of 1 mM Mg2+ and 100 microM Mn2+ enhanced GTPase activity, whereas 5 mM Ca2+ resulted in the increase of Vmax values without significant alterations of K(m). In the presence of A1-specific agonists, Mn2+ and Mg2+ caused a decrease of Vmax values and an increase of GTP affinity. Other cations, such as Co2+, Cd2+, Cu2+, and Zn2+, inhibited the binding capacity but caused almost no changes in GTP hydrolysis kinetics.
Record 39 of 117 in MEDLINE(R)+ (1998-2000)
TI: Solution structure of the motile major sperm protein (MSP) of Ascaris suum - evidence for two manganese binding sites and the possible role of divalent cations in filament formation.
AU: Haaf,-A; LeClaire,-L; Roberts,-G; Kent,-H-M; Roberts,-T-M; Stewart,-M; Neuhaus,-D
SO: J-Mol-Biol. 1998 Dec 18; 284(5): 1611-24
AB: The major sperm protein (MSP) of Ascaris suum mediates amoeboid motility by forming an extensive intermeshed system of cytoskeletal filaments analogous to that formed by actin in many other amoeboid cells. MSP is a dimeric molecule that polymerizes to form non-polar filaments constructed from two helical subfilaments that wind round one another. Moreover, MSP filaments can interact with one another to form higher-order assemblies without requiring the range of accessory proteins usually employed in actin-based systems. A knowledge of how MSP polymerizes and forms the hierarchical series of helical MSP macromolecular assemblies is fundamental to understanding locomotion in these cells. Here we describe the solution structure of MSP dimers determined by NMR spectroscopy under conditions where MSP does not polymerize to form filaments. The solution structure is indistinguishable from that observed in putative MSP subfilament helices by X-ray crystallography, indicating that MSP polymerization is not accompanied by a major conformational change. We also show that the rate of MSP polymerization associated with movement of vesicles in an in vitro motility assay is enhanced by the presence of magnesium and manganese ions and use NMR to show that the primary residues that bind these ions are 24-25 and 83-86. These residues are distant from the interface formed between MSP dimers in subfilament helices, and so are probably not involved in this level of polymerization. Instead the manganese and magnesium ion binding appears to be associated with the assembly of subfilaments into filaments and their subsequent aggregation into bundles. Copyright 1998 Academic Press
Record 40 of 117 in MEDLINE(R)+ (1995-1997)
TI: Characterization of the binding of recombinant mouse sperm fertilin beta subunit to mouse eggs: evidence for adhesive activity via an egg beta1 integrin-mediated interaction.
AU: Evans,-J-P; Kopf,-G-S; Schultz,-R-M
SO: Dev-Biol. 1997 Jul 1; 187(1): 79-93
AB: The sperm protein fertilin (also known as PH-30) is a candidate for mediating the interactions between sperm and egg plasma membranes. Fertilin is a heterodimer. The beta subunit, which has a region with homology to the family of integrin ligands known as disintegrins, has been hypothesized to be involved in the binding of sperm to the egg surface. To investigate this hypothesis and determine what role fertilin beta plays in fertilization, we have expressed the putative extracellular domain of mouse fertilin beta in bacteria as a fusion protein with maltose-binding protein (hereafter referred to as recombinant fertilin beta-EC) and used two assays to characterize its binding to mouse eggs. Immunocytochemistry was used to examine the localization of recombinant fertilin beta-EC binding. A luminometric assay was also developed to quantify levels of binding of recombinant fertilin beta-EC to single eggs. We find that recombinant fertilin beta-EC binds to the region of the plasma membrane of the egg to which sperm bind, thus providing the first direct evidence that fertilin beta has adhesive properties. Peptides corresponding to the disintegrin domain of fertilin beta reduce its binding to eggs, suggesting that this domain is at least partially involved in the recognition of fertilin beta by binding sites on the egg. Treatment of zona pellucida-free eggs with chymotrypsin reduces the ability of the eggs to support the binding of recombinant fertilin beta-EC, implicating an egg surface protein as a binding site for recombinant fertilin beta-EC. Binding of recombinant fertilin beta-EC to eggs is also reduced in the absence of divalent cations and is supported by 2.0 mM Ca2+, Mg2+, or Mn2+. Furthermore, eggs incubated in recombinant fertilin beta-EC prior to in vitro fertilization show reduced levels of sperm binding. Finally, we have examined the possible role of integrins on eggs as receptors for fertilin beta, since an anti-alpha6 integrin subunit monoclonal antibody, GoH3, has been shown to inhibit sperm binding (E. A. C. Almeida et al. (1995) Cell 81, 1095-1104). We find that: (a) an increased amount of GoH3 epitope on the egg surface does not correlate with an increased ability of the eggs to bind sperm or recombinant fertilin beta-EC; (b) the GoH3 antibody has virtually no inhibitory effect on recombinant fertilin beta-EC binding; and (c) recombinant fertilin beta-EC binding is reduced in the presence of anti-beta1 integrin antibodies. These results suggest that a beta1-containing integrin participates in the binding of recombinant fertilin beta-EC to mouse eggs.
CN: HD06274HDNICHD; HD22681HDNICHD; HD22732HDNICHD
Record 41 of 117 in MEDLINE(R)+ (1995-1997)
TI: Expression of superoxide dismutase and xanthine oxidase in myometrium, fetal membranes and placenta during normal human pregnancy and parturition.
AU: Telfer,-J-F; Thomson,-A-J; Cameron,-I-T; Greer,-I-A; Norman,-J-E
SO: Hum-Reprod. 1997 Oct; 12(10): 2306-12
AB: Superoxide, an agent which attenuates the half-life of nitric oxide, is metabolized and synthesized by superoxide dismutase (SOD) and xanthine oxidase, respectively. Over the last few years much work has focused on the role of nitric oxide in human parturition. The aim of this study was to determine whether the onset of human parturition is associated with a change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD), manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the uterus. Samples of myometrium, placenta, decidua and fetal membranes were obtained from women before and after the onset of labour at term. Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like immunoreactivity was detected in syncytiotrophoblast cells, villous stromal cells and endothelial cells of blood vessels in the placenta. In the myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial cells and to some vascular smooth muscle cells. In the fetal membranes we observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion, extravillous trophoblast and decidua. There was no difference in SOD enzyme activity or staining intensity for SOD between different cell types before and during labour. Xanthine oxidase immunoreactivity was identified in each of the tissues examined and again there was no difference in immunostaining in tissues obtained from women delivered before or after the onset of labour. These results show that the pregnant uterus is capable of both synthesizing and degrading superoxide and suggest that superoxide dismutase and xanthine oxidase may play a role in the maintenance of uterine quiescence during pregnancy, but not in the initiation of parturition.
Record 42 of 117 in MEDLINE(R)+ (1995-1997)
TI: Metal exposure studies: role of toxicology and epidemiology in public health policy.
AU: Saric,-M; Piasek,-M
SO: Arh-Hig-Rada-Toksikol. 1997 Sep; 48(3): 307-17
AB: Following the idea of interrelated role of epidemiology and toxicology in risk assessment and dose response evaluation, this paper presents certain experiences from the authors' studies of health effects of environmental exposure to lead and manganese. Epidemiologic observations of adverse effects on female reproductive integrity in a lead smeltery area agree with the experimental data. Animal studies show that the adverse reproductive effects in females are time and dose-related, and reversible after exposure has ceased. Field studies show that effects of manganese on the respiratory system in a polluted region are dose, age and season-related. Cytotoxic effects of manganese, including the inhibitory effect on alveolar macrophages described in in vitro studies on mammalian cells confirm the epidemiologic observations. Authors conclude that in the process of risk assessment, toxicology and epidemiology have to act together. Available human data should be combined with experimental findings and data on the mechanism of toxic action.
Record 43 of 117 in MEDLINE(R)+ (1995-1997)
TI: A direct measurement of increased divalent cation influx in fertilised mouse oocytes.
AU: McGuinness,-O-M; Moreton,-R-B; Johnson,-M-H; Berridge,-M-J
SO: Development. 1996 Jul; 122(7): 2199-206
AB: On fertilisation of mouse oocytes, the fusing spermatozoon triggers a series of repetitive calcium (Ca2+) spikes. The Ca2+ spikes seem to be necessary for successful progression through the cell cycle and are regulated in a cell-cycle-dependent manner. The spikes appear to require the linkage of continuous Ca2+ influx to the periodic release of Ca2+ from intracellular stores by a process of Ca(2+)-induced Ca2+ release. The precise role of Ca2+ influx was explored using the manganese (Mn2+)-quench technique to monitor unidirectional cation influx into single mouse oocytes. There was a marked stimulation of cation influx associated closely with the upsweep of the first and subsequent fertilisation Ca2+ spikes. A smaller but significant increase in the rate of cation influx persisted in the interspike period in fertilised oocytes. Spike-associated entry was not as apparent in oocytes stimulated to spike repetitively by thimerosal or acetylcholine application. Instead, there was a continuous increase in cation influx underlying Ca2+ spiking which commenced with the onset of the first spike. Using the specific microsomal inhibitor thapsigargin and the Ca2+ ionophore ionomycin, we found evidence for a capacitative entry mechanism in mouse oocytes. We propose that the persistent influx of Ca2+ observed in response to all stimuli examined is controlled by a capacitative mechanism and sets the frequency of spiking by determining the time taken to refill the internal stores to a point where they are again sensitive enough to initiate the next spike.
Record 44 of 117 in MEDLINE(R)+ (1995-1997)
TI: Zinc acetate and lyophilized aloe barbadensis as vaginal contraceptive.
AU: Fahim,-M-S; Wang,-M
SO: Contraception. 1996 Apr; 53(4): 231-6
AB: Twenty samples of fresh ejaculate, donated by healthy volunteers ranging in age from 20-30 years, were obtained from the Center for Fertility & Cryobiology, University of Missouri, Columbia, Missouri. Average semen volume was 2.49 ml; average sperm motility was 71.32%; and average sperm density was 113.71 x 10(6) /ml. Testing for spermicidal effectiveness of a 1% concentration of zinc acetate, zinc sulfate, zinc chloride, and zinc gluconate proved that only zinc acetate was spermicidal. It appears this is due to the acetate in zinc acetate which may decrease oxygen utilization by sperm. Zinc acetate in vitro was antiviral while lyophilized aloe barbadensis was not. Lyophilized aloe barbadensis at concentrations of 7.5% and 10% proved to be spermicidal due to the multiple micro elements (boron, barium, calcium, chromium, copper, iron, potassium, magnesium, manganese, phosphorus, and zinc) which were toxic to the tail causing instant immobilization. The two compounds did not irritate or cause ulceration of rabbit vaginal epithelium. These results suggest the possibility of using zinc acetate and lyophilized aloe barbadensis as a new, effective and safe vaginal contraceptive.
Record 45 of 117 in MEDLINE(R)+ (1995-1997)
TI: Developmental expression of glutathione peroxidase, catalase, and manganese superoxide dismutase mRNAs during spermatogenesis in the mouse.
AU: Gu,-W; Hecht,-N-B
SO: J-Androl. 1996 May-Jun; 17(3): 256-62
AB: We have examined in mouse testis the steady-state levels of mRNAs encoding glutathione peroxidase (GSHPx), catalase (CAT), and superoxide dismutase 2 (SOD-2), three enzymes essential for the antioxidant protection of cells. In RNA preparations derived from prepuberal and adult testes and from isolated populations of meiotic and post-meiotic germ cells, one major GSHPx mRNA of about 0.8 kilobases (kb) and one major CAT mRNA of about 2.4 kb were detected. Three SOD-2 mRNAs of about 2.2, 1.2, and 1.0 kb were found in testis. In contrast to GSHPx and CAT, the mRNA levels of SOD-2 were higher in testis than in liver. SOD-2 mRNA levels are developmentally and translationally regulated with maximal levels of expression in early post-meiotic germ cells, whereas the levels of GSHPx and CAT mRNAs are relatively constant in both prepuberal and adult testes. These data suggest that translational regulation plays a more prominent role for SOD-2 expression than for GSHPx or CAT expression in the mammalian testis.
Record 46 of 117 in MEDLINE(R)+ (1995-1997)
TI: Expression of manganese superoxide dismutase mRNA in reproductive organs during the ovulatory process and the estrous cycle of the rat.
AU: Nomura,-T; Sasaki,-J; Mori,-H; Sato,-E-F; Watanabe,-S; Kanda,-S; Matsuura,-J; Watanabe,-H; Inoue,-M
SO: Histochem-Cell-Biol. 1996 Jan; 105(1): 1-6
AB: Expression of manganese superoxide dismutase (Mn-SOD) mRNA during the pregnant mare serum gonadotrophin (PMSG)/human chorionic gonadotrophin (HCG)-induced ovulatory process, and during the estrous cycle was examined in rat female reproductive organs. Mn-SOD mRNA levels in theca interna cells markedly increased in PMSG-primed rats and high levels of the transcripts were maintained after HCG injection. The PMSG-enhanced expression of Mn-SOD mRNA in follicular epithelial cells increased concomitantly with luteinization of these cells. The levels of Mn-SOD mRNA remained high and became equivalent in both granulosa and theca lutein cells 24 h after HCG injection. Neither luteinization nor the expression of Mn-SOD mRNA was observed in the epithelial cells of unovulated follicles. Luteal bodies had formed 3 days after HCG injection, and the same level of Mn-SOD mRNA expression continued in lutein cells, but not in stromal cells. During the estrous cycle, Mn-SOD mRNA was localized to theca interna cells on proestrus, to the epithelial cells of luteinizing follicles on estrus, and to newly formed luteal bodies on diestrus. The epithelial cells in the oviduct did not express Mn-SOD mRNA throughout the ovulatory process or the estrous cycle. Expression of Mn-SOD mRNA in the luminal epithelial cells of the uterus increased after PMSG injection, reaching a maximum after 24 h, and became relatively negative 3 days after HCG injection when corpora lutea had formed in the ovary. During the estrous cycle, uterine epithelial cells and leukocytes showed marked increases in Mn-SOD mRNA expression on estrus and on proestrus, respectively. Expression in the vaginal epithelium became apparent 3 days after HCG injection and continued for at least 12 days after HCG injection. The expression was localized to the superficial layer of the epithelium. During the estrous cycle, expression occurs in the basal layer on proestrus and estrus, transferring to the superficial layer on diestrus day 1, and expression stops on diestrus day 2. The relationship between the expression of Mn-SOD mRNA and hormone-induced metabolic changes, including steroidogenesis, is discussed.
Record 47 of 117 in MEDLINE(R)+ (1995-1997)
TI: Adenylate cyclase activity increases concomitantly with the onset of capacitation in heparin-treated bovine spermatozoa.
AU: Ijaz,-A; Fortier,-M-A; Sirard,-M-A
SO: Reprod-Nutr-Dev. 1996; 36(2): 221-32
AB: This study examined the effect of metal ions Ca2+, Mg2+, and Mn2+ and sonication on ejaculated frozen-thawed bovine sperm adenylate cyclase activity, and whether cAMP levels in sperm changed during capacitation with heparin. The sperm adenylate cyclase was almost insensitive to Ca2+ at concentrations up to 10 mM when cold-shocked homogenized spermatozoa were used. Adenylate cyclase activity, as observed by cAMP formation (pmol/mg protein/min), did not increase significantly in the presence of 5 mM Mg2+. However, a 40-fold stimulation (cAMP 400-800 pmol/mg protein/min) occurred in the presence of 5 mM Mn2+. Although Ca2+ per se had no effect, it acted synergistically with Mg2+ and Mn2+ in stimulating sperm adenylate cyclase. Adenylate cyclase activity was highest in cold-shocked, homogenized spermatozoa. Sonication of cold-shocked spermatozoa resulted in loss of adenylate cyclase activity, and a logarithmic decrease in cAMP production (1,155.5 to 109.7 pmol cAMP) occurred when sonication was increased from 2 x 5 to 2 x 25 s on ice. Cyclic AMP levels in spermatozoa incubated under non-capacitating conditions, both untreated and treated with glucose or heparin plus glucose, remained higher (P < 0.01) compared with those incubated with heparin for the first 4 h of incubation. When spermatozoa were incubated under non-capacitating conditions, cAMP levels increased (P < 0.01), especially during the first hour of incubation, and then declined gradually throughout the incubation. In contrast, cAMP levels of heparin-treated spermatozoa declined gradually for 3 h, at which time they began to rise, peaked at 4 h and then remained fairly stable until 6 h. Glucose antagonized the effect of heparin on adenylate cyclase activity but not for more than 4 h. We conclude that: i) Ca2+ stimulates adenylate cyclase in the presence of Mg2+; ii) homogenization by sonication reduces cyclase activity in frozen-thawed, cold-shocked spermatozoa; iii) adenylate cyclase activity is inhibited by heparin but rises concomitantly with the onset of capacitation (after 4 h) in spermatozoa incubated under capacitating conditions; and iv) glucose, which prevents capacitation by heparin, antagonizes heparin action on adenylate cyclase.
Record 48 of 117 in MEDLINE(R)+ (1995-1997)
TI: Modulation of postthaw motility, survival, calcium uptake, and fertility of bovine sperm by magnesium and manganese.
AU: Lapointe,-S; Ahmad,-I; Buhr,-M-M; Sirard,-M-A
SO: J-Dairy-Sci. 1996 Dec; 79(12): 2163-9
AB: Because Mg2+ and Mn2+ are potent stimulators of motility through the stimulation of adenylate cyclase activity, the current study was undertaken to modulate the fertilizing ability of bovine semen by incorporation of various concentrations of those two salts in extenders before freezing. Motility analysis at 6 h in vitro showed a positive effect of MgCl2 in a dose-dependent manner from 0.5 to 5 mM (31 to 50%). Manganese at the concentration of 0.1 mM also supported good sperm motility (53%) compared with that of the control (28%). Although survival was increased, no detrimental effects were seen on the number of sperm that penetrated mucus of cows in estrus. The intracellular Ca2+ concentration of sperm was very different across treatments after thawing; spermatozoa that were extended with 2 mM MgCl2 and 0.5 mM MnCl2 possessed the highest concentrations at thawing. Four hours later, in the presence of Ca, spermatozoa that were extended in 0.1 mM MnCl2 showed the highest uptake. In the presence of Ca and heparin, spermatozoa that were extended in different amounts of Mg showed Ca2+ concentrations that increased in a dose-dependent manner. This effect was negated by glucose. Functional fertilizing capacity was also evaluated by in vitro fertilization, and the different treatments did not show any detrimental effects. In summary, 5 mM MgCl2 and 0.1 mM MnCl2 both have beneficial effects for the maintenance of sperm motility without detrimental effects on mucus penetration and fertilizing ability. Furthermore, these treatments do not prevent subsequent Ca2+ uptake in response to heparin. These in vitro studies are potentially a good sorting system to predict the benefits of extender modifications.
Record 49 of 117 in MEDLINE(R)+ (1995-1997)
TI: Biophysical and biochemical analysis of semen in infertile Nigerian males.
AU: Adejuwon,-C-A; Ilesanmi,-A-O; Ode,-E-O; Akinlade,-K-S
SO: Afr-J-Med-Med-Sci. 1996 Sep; 25(3): 217-9
AB: Biophysical analysis of semen was performed in fifty-eight Nigerian male partners of infertile marriages. Sperm count concentration was significantly higher (P < 0.001) in oligospermics compared to normospermics as expected. However, there was no significant difference in sperm volume or motility percentage between the normospermics and the oligospermics; of course, no sperms were seen in the azoospermics. Biochemical analyses of serum zinc, copper, magnesium, and manganese by atomic absorption spectrophotometry  were further correlated in fifty-two patients. There were no statistically significant differences observed in the serum levels of zinc, magnesium, and copper among the normospermics, oligospermics, and azoospermics. The normospermic infertile patients, however, exhibited higher serum manganese when compared with oligospermics and azoospermics (P < 0.001). This finding suggests a potential role for manganese in the evaluation of infertile males.
Record 50 of 117 in MEDLINE(R)+ (1995-1997)
TI: Effects of barium, lanthanum and gadolinium on endogenous chloride and potassium currents in Xenopus oocytes.
AU: Tokimasa,-T; North,-R-A
SO: J-Physiol. 1996 Nov 1; 496 ( Pt 3)677-86
AB: 1. The effects of multivalent cations on membrane currents recorded from Xenopus oocytes were studied. 2. The hyperpolarization-activated chloride current was reversibly blocked by lanthanum; half-maximal block occurred at a concentration of 8 microM. Zinc, cadmium, cobalt and nickel were less potent than lanthanum, and gadolinium, manganese, barium and strontium had no effect at a concentration of 100 microM. 3. The calcium-activated chloride current was blocked by gadolinium (50 microM), and lanthanum, cadmium, cobalt, nickel and manganese were equally effective. The actions of gadolinium and lanthanum were almost irreversible, while partial (30-80%) recovery was observed with the other cations. Zinc (100 microM) had no effect. 4. In lanthanum (100 microM), membrane depolarizations from -70 mV activated an outward potassium current that was partially blocked by barium (0.1-2 mM). The barium-sensitive current was confined to potentials less negative than -70 mV. The current consisted of a time-independent as well as a time-dependent component, the latter of which had voltage dependence similar to the M-current. 5. It is proposed that lanthanum, gadolinium and barium can usefully separate these endogenous membrane currents in Xenopus oocytes.
Record 51 of 117 in MEDLINE(R)+ (1995-1997)
TI: Mouse sperm membrane potential: changes induced by Ca2+.
AU: Espinosa,-F; Darszon,-A
SO: FEBS-Lett. 1995 Sep 18; 372(1): 119-25
AB: Mouse sperm resting membrane potential (Er) (-42 +/- 8.8 mV), determined with a potential sensitive dye, depended on extracellular K+ and, in the absence of extracellular Ca2+ ([Ca2+]e), on external Na+ ([Na+]e). Ca2+ addition (> 5 microM) to sperm in Ca-free media induced a transient hyperpolarization (Ca-ith) which strongly depended on [Na+]e and less on external Cl- ([Cl-]e). Cd2+ and Mn2+ (microM) mimicked the Ca2+ effect, but not Ba2+. The Ca-ith was partially inhibited by ouabain (74%, IC50 = 5.8 microM) and niflumic acid (38%, IC50 = 240 microM), indicating the participation of the Na-K ATPase and Cl- channels. In Ca-free low-Na+ media, Ca2+ addition caused a depolarization sensitive to: nimodipine (25 microM), trifluoperazine (12.5 microM) and Mg2+ (1.2 mM), suggesting the participation of Ca2+ channels. Since some inhibitors of the sperm Ca-ith block the acrosome reaction (AR), both processes may share transport systems.
Record 52 of 117 in MEDLINE(R)+ (1995-1997)
TI: The coelomic cavity--a reservoir for metals.
AU: Wathen,-N-C; Delves,-H-T; Campbell,-D-J; Chard,-T
SO: Am-J-Obstet-Gynecol. 1995 Dec; 173(6): 1884-8
AB: OBJECTIVE: The concentrations of metals in fluids surrounding the first-trimester fetus were measured. STUDY DESIGN: Atomic absorption spectrometry was used to measure concentrations of metals in matched samples of amniotic and extraembryonic coelomic fluids in 17 women between 9 and 12 weeks of pregnancy. RESULTS: Concentrations of calcium, magnesium, iron, copper, and manganese (but not zinc, cadmium, or lead) were significantly higher in coelomic than in amniotic fluid. There was no significant difference between levels of iron, manganese, and lead in controls and amniotic fluid or between concentrations of manganese, cadmium, and lead in controls and coelomic fluid. There was no relationship between the concentrations of each metal in amniotic and coelomic fluid. CONCLUSION: The extraembryonic coelom is an important site of concentration of metals in early pregnancy. This might represent a store of metals essential for normal embryonic and fetal development or constitute a defense mechanism against environmental conditions adverse to the fetus.
Record 53 of 117 in MEDLINE(R)+ (1995-1997)
TI: Glycosidic specificity of fucosyltransferases present in rat epididymal spermatozoa.
AU: Raychoudhury,-S-S; Millette,-C-F
SO: J-Androl. 1995 Sep-Oct; 16(5): 448-56
AB: We have recently demonstrated multiple fucosyltransferase (FT) activity in rat spermatogenic cells. To complement these findings, here we identify and partially characterize the glycosidic linkage specificity of FTs present in spermatozoa from caput and cauda epididymides. Analysis of the acceptor substrate specificity of the FTs by thin-layer chromatography indicated that both caput and cauda sperm expressed alpha(1-2)-, alpha(1-3)-, alpha(1-4)-FTs as demonstrated by fucose incorporation into phenyl-beta-D-galactoside, 2'-fucosyllactose, and lacto-N-fucopentaose-I, respectively. Spermatozoa from the cauda epididymidis exhibited significant decreases in the levels of alpha(1-2)-, alpha(1-3)-, alpha(1-4)-FTs, and of total soluble FTs in comparison to spermatozoa from the caput epididymidis. The relative ratio of alpha(1-3)-FT to total FT activity appeared to be significantly higher than those of alpha(1-2)- or alpha(1-4)-FTs, in spermatozoa both from caput and cauda epididymides. Using different types of low molecular weight acceptors and the selective inhibition of the FT by N- ethylmaleimide, we have demonstrated that at least alpha(1-2)-FT is different from alpha(1-3)- or alpha(1-4)-FTs. Kinetic studies also showed that alpha(1-2)-FT is different from alpha(1-3)- or alpha(1-4)-FTs as demonstrated by apparent Km and Vmax values. Moreover, alpha(1-3)- and alpha(1-4)-FT activities in cauda sperm were found to be highly sensitive to Mn2+ but showed differential responses to divalent cations. In contrast, both alpha(1-3)- and alpha(1-4)-FTs seemed to be relatively less sensitive to Mg2+. Thus, these results not only demonstrate the presence of multiple FTs in rat epididymal sperm but also differentiate individual FTs with regard to their kinetic properties and sensitivity to both inhibitor and divalent cations.
Record 54 of 117 in MEDLINE(R)+ (1995-1997)
TI: Mouse sperm adenylyl cyclase: general properties and regulation by the zona pellucida.
AU: Leclerc,-P; Kopf,-G-S
SO: Biol-Reprod. 1995 Jun; 52(6): 1227-33
AB: It has been shown that the cAMP concentrations in capacitated mouse sperm can be increased in response to the egg's extracellular matrix, the zona pellucida (ZP), during the acrosome reaction. However, it is not known whether this cAMP elevation is caused by a stimulation of adenylyl cyclase (AC) activity or a decrease in cyclic nucleotide phosphodiesterase activity. In the present study using capacitated mouse spermatozoa, 20% and 30% of the total AC activity in the presence of Mg2+ and Mn2+, respectively, was measured in the sperm membrane fraction that contained the highest specific AC activity. As reported in other studies of sperm AC, Mn(2+)-supported AC activity was 15-30 times higher than Mg(2+)-supported AC activity. Interestingly, when the membrane fraction was solubilized with Lubrol-PX, an increase in specific and total Mg(2+)-supported AC activity was obtained while a decrease in both the specific and total Mn(2+)-supported AC activity was observed. In the absence of detergent, the ZP stimulates the membrane AC in a concentration-dependent manner, but this stimulation is observed only when the enzyme activity is measured in the presence of Mg2+. Forskolin also stimulates the Mg(2+)-but not the Mn(2+)-supported AC activity, and this effects is not additive to or synergistic with the ZP stimulation of the membrane AC. Results reported in this study suggest that ZP-mediated stimulation of membrane-associated AC may represent a mechanism by which the ZP affects sperm functions.
Record 55 of 117 in MEDLINE(R)+ (1993-1994)
TI: Partial characterization of galactosyltransferase in human seminal plasma and its distribution in the human epididymis.
AU: Ross,-P; Vigneault,-N; Provencher,-S; Potier,-M; Roberts,-K-D
SO: J-Reprod-Fertil. 1993 May; 98(1): 129-37
AB: Galactosyltransferase activity has been partially characterized in human seminal plasma. Km values of 130 mumol l-1 for UDP-galactose and 2.25 mmol l-1 for N-acetylglucosamine were calculated and the enzyme was found to be dependent on temperature and manganese and present as a highly active component of human seminal plasma. Galactosyltransferase was inhibited by nucleotides, glycosylated nucleotides, bovine and human alpha-lactalbumin but not by monosaccharides. Radiation inactivation studies revealed that the biologically active unit of seminal plasma galactosyltransferase has a molecular mass of 45 kDa. Although the majority of galactosyltransferase activity found in seminal plasma is probably of prostatic origin, we report for the first time that it is also present in human epididymal intraluminal fluid. Low activity was detected in the proximal caput region but activity increased to maximum values in the adjacent downstream segment, the intermediate caput region. Specific activity was relatively constant albeit at a lower value in the following epididymal segments and vas deferens. The significance of the epididymal and seminal plasma galactosyltransferase activities is unknown, but the enzyme could be implicated in glycosylation events that are known to be important in gamete interaction.
Record 56 of 117 in MEDLINE(R)+ (1993-1994)
TI: Effects of the workplace on fertility and related reproductive outcomes.
SO: Environ-Health-Perspect. 1993 Jul; 101 Suppl 281-90
AB: This report reviews the recent literature on the adverse effects of occupational factors on fertility and related reproductive outcomes. Few studies fulfill the criteria of good study design because of small sample size, insensitive measures of effect, selection, recall, and observation bias, weak if any control of confounding factors, bad definition of exposure, inability to analyze a dose-response relationship, and inadequate statistical analysis. The high prevalence of unsuccessful reproductive outcomes in the general population makes the design of human fertility studies difficult. Although a number of publications indicate that certain occupational factors and settings adversely affect both male and female fertility, it is virtually impossible to estimate the proportion of infertility due to occupational factors in the general population. The collected data suggest that the exposure to the following substances or occupational settings may affect a function of male genital system, leading to sperm abnormalities, hyperestrogenism, impotence, infertility, and/or increased spontaneous abortion rate in wives of exposed workers: alkylmercury, antimonide, anesthetic gases, boron, carbon disulfide, chlorodecone, chloroprene, some carbamates (carbaryl), diaminostilbene, 1,2-dibromo-3-chloropropane, ethylene glycol ethers, ethylene dibromide, inorganic lead, manganese, methyl chloride, organic solvents, synthetic estrogens and progestins, tetraethyllead, combined exposure to styrene and acetone, welding operations, and heat. The majority of reviewed papers on female fertility concerns the alterations of menstrual cycle and pregnancy complications rather than occupational exposure-induced female infertility. The literature supports the hypothesis that, in general, working women have a tendency of higher risk of unsuccessful reproductive outcomes, although the existing data are not sufficient.
Record 57 of 117 in MEDLINE(R)+ (1993-1994)
TI: Provocation testing of human sperm motility using energy substrates and activators of the cyclic nucleotide system: II. Studies on sperm from asthenozoospermic subjects.
AU: Magnus,-O; Abyholm,-T; Brekke,-I; Purvis,-K
SO: Int-J-Fertil. 1993 Mar-Apr; 38(2): 123-8
AB: OBJECTIVE--To find differences in effect on sperm motility of agents that increase intracellular cAMP: manganese ion, methyl-isobutyl-xanthine (MIX), 2-deoxyadenosine, glucose, and Mn-MIX and Mn-glucose. DESIGN--Nine men with asthenozoospermia vs. fertile donors. METHODS--Sperm was washed in Hepes-buffered saline, motility tested by laser-Doppler technique. RESULTS--Best activation was obtained with Mn and 2-deoxyadenosine; generally poor response to MIX or glucose. CONCLUSIONS--Usually, poor endogenous stimulation of adenylyl cyclase, and probably not limited energy supply, is the cause of impaired motility.
Record 58 of 117 in MEDLINE(R)+ (1993-1994)
TI: Evidence for a novel adenylyl cyclase in human epididymal sperm.
AU: Rojas,-F-J; Patrizio,-P; Do,-J; Silber,-S; Asch,-R-H; Moretti-Rojas,-I
SO: Endocrinology. 1993 Dec; 133(6): 3030-3
AB: Since cAMP is considered to play a major role in the acquisition of maturation and fertilizing capacity of mammalian sperm, we investigated the expression of cAMP-synthesizing adenylyl cyclase (AC) in sperm retrieved directly from the human epididymis. Particulate fractions were prepared from purified epididymal sperm samples and AC was monitored by the direct conversion of ATP into cAMP. We report that in great contrast to human ejaculated sperm and other mammalian sperm cells, the human epididymal sperm do not express a Mn(2+)-sensitive AC. However, a functional AC was readily detectable in these sperm cells in the presence of saturating concentrations of Ca2+ (50mM) and bicarbonate (HCO3-, 50mM), a combination that causes maximal activation in human ejaculated sperm. Using these conditions, human epididymal sperm AC showed similar capacity to generate cAMP compared to human ejaculated sperm AC. When assays were performed in the presence of Mg2+ and a saturating concentration of GMP-P(NH)P (50 microM), the hydrolysis-resistant GTP analog, and forskolin (100 microM), no activity was detected indicating that the epididymal sperm AC differs from that in somatic cells. These data demonstrate that human epididymal sperm contain an AC that is unique and different from the enzyme system described in somatic cells and other mammalian sperm cells, including human ejaculated sperm.
Record 59 of 117 in MEDLINE(R)+ (1990-1992)
TI: Provocation testing of human sperm motility using energy substrates and activators of the cyclic nucleotide system. I. Establishment of conditions for response testing.
AU: Magnus,-O; Abyholm,-T; Brekke,-I; Purvis,-K
SO: Int-J-Fertil. 1992 Mar-Apr; 37(2): 115-22
AB: In order to establish a series of provocation tests to evaluate the integrity of the sperm cAMP pathway, manganese (Mn), 2-deoxyadenosine (DEA) (via adenylyl cyclase), and methyl-isobutyl-xanthine (MIX) (via phosphodiesterase) were tested for their capacity to activate the progressive motility of human sperm. Optimal responses were obtained using washed sperm previously incubated for 3 hours in substrate-poor medium (Hepes-buffered saline). Longer periods of incubation required the presence in addition of an energy substrate such as glucose. Exposure of sperm to seminal plasma for 24 hours prior to washing attenuated the responsiveness of the sperm to the different activators. Preliminary studies on the activation of the progressive motility of washed sperm from four normozoospermic men under fertility investigation, prepared under identical conditions, revealed differences in the pattern of response which may have pathophysiological relevance.
Record 60 of 117 in MEDLINE(R)+ (1990-1992)
TI: Fertility of male workers exposed to cadmium, lead, or manganese.
AU: Gennart,-J-P; Buchet,-J-P; Roels,-H; Ghyselen,-P; Ceulemans,-E; Lauwerys,-R
SO: Am-J-Epidemiol. 1992 Jun 1; 135(11): 1208-19
AB: The effect of exposure to cadmium, lead, or manganese on male reproductive function was examined in 1988-1989 in Belgian blue-collar workers. The workers were exposed to cadmium in two smelters (n = 83; geometric mean urinary cadmium level = 6.94 micrograms/g of creatinine; mean duration of exposure = 24 years), to lead in a battery factory (n = 74; mean blood lead level = 46.3 micrograms/dl; mean duration of exposure = 10.7 years), or to manganese (manganese dioxide) in a dry alkaline battery plant (n = 70; median atmospheric concentration of total manganese dust = 0.71 mg/m3; mean duration of exposure = 6.2 years). Fertility in these workers and in an unexposed population (n = 138) was assessed by examining the birth experiences of their wives through a logistic regression model. The probability of a live birth was not different between the unexposed workers and the cadmium- or manganese-exposed workers before or after the onset of exposure. While the fertility of the lead-exposed workers was somewhat greater than that of the unexposed before the onset of exposure, a significant decrease in fertility was observed during the period of exposure to the metal (odds ratio = 0.65, 95% confidence interval 0.43-0.98).
Record 61 of 117 in MEDLINE(R)+ (1990-1992)
TI: Superoxide dismutase activity, lipid peroxide production and corpus luteum steroidogenesis during natural luteolysis and regression induced by oestradiol deprivation of the ovary in pseudopregnant rabbits.
AU: Hesla,-J-S; Miyazaki,-T; Dasko,-L-M; Wallach,-E-E; Dharmarajan,-A-M
SO: J-Reprod-Fertil. 1992 Aug; 95(3): 915-24
AB: The relationship of oxygen free radicals to corpus luteum function in rabbits was explored during various stages of pseudopregnancy, including natural and induced luteal regression. Induced luteolysis was achieved during mid-pseudopregnancy by removal of an oestradiol capsule placed at the onset of pseudopregnancy, which suppressed ovarian oestradiol production. Activity of manganese superoxide dismutase (Mn SOD) was significantly and positively correlated with ovarian progesterone production (P < 0.01) throughout pseudopregnancy and during natural regression. Oestradiol deprivation for 12, 24 or 72 h resulted in declines in Mn SOD activity and progesterone secretion, although Mn SOD rose and corpus luteum steroidogenesis was restored to normal when the capsule was replaced for 48 h before assessment, having been removed for 24 h. Lipid peroxide and progesterone concentrations were not correlated, although a significant rise in lipid peroxides in the luteal tissue was detected after deprivation of oestradiol for 72 h. Changes in progesterone production and Mn SOD activity were not associated with alterations in concentration of prostaglandin F metabolite. These data suggest that Mn SOD may be involved in regulating function of the corpus luteum during pseudopregnancy in rabbits and that oxygen free radicals may play a role in regression of corpus luteum in this species.
CN: HD06268HDNICHD; HD19430HDNICHD
Record 62 of 117 in MEDLINE(R)+ (1990-1992)
TI: Intestinal transfer of manganese: resemblance to and competition with calcium.
AU: Dupuis,-Y; Porembska,-Z; Tardivel,-S; Fournier,-A; Fournier,-P
SO: Reprod-Nutr-Dev. 1992; 32(5-6): 453-60
AB: The effect of calcium, phosphate and the sugars lactose and sorbitol on the intestinal absorption of manganese were studied in adult male rats. Gastric gavage showed that lactose (100 mM or 200 mM) increased the hepatic retention of 54Mn, while phosphate decreased it. In situ ileal loop studies indicated that Mn absorption was normally complete in 30 min. Sorbitol had no effect on uptake during this period, but extended Mn absorption from 30 min to 120 min. Low concentrations of Mn (10 microM) did not alter the enhancing effect of lactose on calcium transport (10 mM), but the enhancing effect of lactose on Mn transport was blocked by this high calcium concentration. Intestinal alkaline phosphatase activity was rapidly stimulated by Mn. These similarities plus the competition between cations, especially calcium, suggest that a common mechanism exists in their intestinal transport.
Record 63 of 117 in MEDLINE(R)+ (1990-1992)
TI: Regulation of cyclic adenosine monophosphate synthesis in human ejaculated spermatozoa. I. Experimental conditions to quantitate membrane-bound adenylyl cyclase activity.
AU: Rojas,-F-J; Bruzzone,-M-E
SO: Hum-Reprod. 1992 Sep; 7(8): 1126-30
AB: Although cyclic adenosine monophosphate (cAMP) is an important regulator of motility and metabolism in human spermatozoa, little is known on the cellular system responsible for its synthesis. Here, we investigated the experimental conditions directly to quantitate adenylyl cyclase (AC) activity synthesizing cAMP in human ejaculated spermatozoa and analysed the general properties of the enzyme. A 10,000 g membrane fraction was prepared from washed sperm cells homogenized by sonication. AC activity was monitored by the direct conversion of [alpha-32P]adenosine triphosphate (ATP) into [32P]cAMP. Using a nucleoside triphosphate regenerating system to ensure availability of ATP substrate, the human sperm AC showed a steady production of cAMP for at least 1 h. The assay was optimized for pH, buffer concentration, membrane protein and substrate concentration. Activity was dependent upon the presence of Mn2+ as a divalent cation and showed a pH optimum between 7.0 and 8.5. Optimal activity required 5 mM ATP, 1 mM ethylenediamine tetraacetic acid (EDTA) and 20-40 mM total MnCl2. Dependence on Mn2+ was not mandatory; Mg2+ at 5-40 mM also supported significant activity, but the activity was 4-6 times lower than that with Mn2+. Regardless of the presence of Mn2+ or Mg2+ as divalent cation in the assay, human sperm AC was insensitive to the regulatory ligands NaF, guanine nucleotide or forskolin. Insensitivity to these ligands supports the proposal that this enzyme system does not contain a stimulatory guanine nucleotide-binding regulatory protein and that its catalytic component is unique and different from that of somatic cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Record 64 of 117 in MEDLINE(R)+ (1990-1992)
TI: Regulation of cyclic adenosine monophosphate synthesis in human ejaculated spermatozoa. II. The role of calcium and bicarbonate ions on the activation of adenylyl cyclase.
AU: Rojas,-F-J; Bruzzone,-M-E; Moretti-Rojas,-I
SO: Hum-Reprod. 1992 Sep; 7(8): 1131-5
AB: In this study, we have applied our previous data describing the experimental conditions necessary for expression of cyclic adenosine monophosphate (cAMP)-synthesizing adenylyl cyclase in human ejaculated spermatozoa, to investigate the direct effects of calcium (Ca2+) and bicarbonate (HCO3-) upon activation of the enzyme in vitro. We report that the effects of Ca2+ and HCO3- were significantly dependent on the status of the enzyme activity. Thus, at a near saturating (10 mM) concentration of MnCl2 giving high enzyme activity, addition of less than 10 mM HCO3- did not affect adenylyl cyclase activity and higher concentrations inhibited the enzyme, with 50 mM HCO3- reducing the activity by 33%. Also, addition of less than 20 mM CaCl2 alone or in combination with 10 mM HCO3- did not significantly change the enzyme activity. In great contrast, enzyme activation was highly responsive to Ca2+ and HCO3- when MnCl2 was present at a concentration giving submaximal enzyme activity. Thus, at 2 mM MnCl2, adenylyl cyclase was markedly increased by CaCl2 concentrations between 10 and 100 mM. The activation was further enhanced by increasing concentrations of HCO3-, with 50 mM HCO3- giving the highest activity at 50-100 mM CaCl2. Activation by CaCl2 was also observed in the absence of added MnCl2, being significantly greater than basal activity at 10 mM CaCl2 and maximal at 100 mM CaCl2.(ABSTRACT TRUNCATED AT 250 WORDS)
Record 65 of 117 in MEDLINE(R)+ (1990-1992)
TI: Trace element deficiencies in cattle.
SO: Vet-Clin-North-Am-Food-Anim-Pract. 1991 Mar; 7(1): 153-215
AB: Deficiency of cobalt, copper, iron, iodine, manganese, selenium, or zinc can cause a reduction in production. Reduced production occurs most commonly when a deficiency corresponds to the phases of growth, reproduction, or lactation. Because of environmental, nutrient, disease, genetic, and drug interactions, deficiencies of single or multiple elements can occur even when the levels recommended by the National Research Council for these nutrients are being fed. Additionally, random supplementation of trace elements above National Research Council recommendations is not justified because of the negative interaction among nutrients and potential toxicosis. Evaluation of trace element status can be difficult because many disease states will alter blood analytes used to evaluate nutrient adequacy. Proper dietary and animal evaluation, as well as response to supplementation, are necessary before diagnosing a trace element deficiency.
Record 66 of 117 in MEDLINE(R)+ (1990-1992)
TI: Comparison of clastogenicity of inorganic Mn administered in cationic and anionic forms in vivo.
AU: Joardar,-M; Sharma,-A
SO: Mutat-Res. 1990 Mar; 240(3): 159-63
AB: A comparison of the cytotoxic activity of cationic (MnSO4) and anionic (KMnO4) salts of inorganic manganese in the mouse in vivo indicated that the former was more strongly clastogenic than the latter. Mice were administered different doses of the salt orally over a period of 3 weeks. In general, both the frequencies of chromosomal aberrations in bone marrow cells and micronuclei were increased significantly by both salts. Sperm-head abnormalities showed a significant enhancement as well. The clastogenic effects were directly related to the concentrations used and were not markedly influenced by the duration of treatment. In view of the known affinity of Mn2+ for chromosomal components, it has been suggested that the effects were mediated by these ions produced directly from MnSO4 and indirectly from KMnO4 following conversion under acidic pH of the gastric juices.
Record 67 of 117 in MEDLINE(R)+ (1990-1992)
TI: Effects of manganese and other divalent cations on progressive motility of human sperm.
AU: Magnus,-O; Brekke,-I; Abyholm,-T; Purvis,-K
SO: Arch-Androl. 1990; 24(2): 159-66
AB: Manganese (Mn2+) stimulated the progressive motility of human washed sperm in a time- and dose-dependent manner. This confirmed previous data indicating a capacity for activating the adenylyl cyclase of sperm homogenates in vitro. A maintained response was best seen with doses 0.2-1.0 mM. After an initial stimulation, higher concentrations of up to 20 mM were associated with a decline in the response to control levels. Magnesium ions (Mg2+) stimulated motility in the same dose range but to less than 50% of the Mn2+ response. Other divalent cations such as zinc (Zn2+), strontium (Sr2+), and Calcium (Ca2+) also exerted stimulatory effects to varying degrees in descending order. Metal ion effects on sperm motility may be mediated through a common cation-binding site on the adenylyl cyclase.
Record 68 of 117 in MEDLINE(R)+ (1990-1992)
TI: Effect of inositol trisphosphate and calcium on oscillating elevations of intracellular calcium in Xenopus oocytes.
AU: DeLisle,-S; Krause,-K-H; Denning,-G; Potter,-B-V; Welsh,-M-J
SO: J-Biol-Chem. 1990 Jul 15; 265(20): 11726-30
AB: Stimulation of many nonexcitable cells by Ca2(+)-mobilizing receptor agonists causes oscillating elevations of the intracellular free Ca2+ concentration ((Ca2+]i), rather than a continuous increase. It has been proposed that the frequency at which [Ca2+]i oscillates determines the biological response. Because the occurrence of [Ca2+] oscillations is observed together with endogenous inositol polyphosphate (InsPs) production or following InsPs application, we injected Xenopus laevis oocytes with InsPs and monitored Ca2(+)-activated Cl- currents as an assay of [Ca2+]i. Microinjection of the poorly metabolizable inositol trisphosphate (InsP3) derivatives inositol 2,4,5-trisphosphate (Ins(2,4,5)P3) and inositol 1,4,5-trisphosphorothioate (Ins(1,4,5) P3S3) induced [Ca2+]i oscillations. The frequency at which [Ca2+]i oscillated increased with the injected dose, indicating that the frequency-generating mechanism lies distal to InsP3 production and that generation of oscillations does not require either oscillation of InsP3 levels or InsP3 metabolism. Injections of high doses of Ins(1,4,5)P3 or Ins(2,4,5)P3 inhibited ongoing oscillations, whereas Ca2+ injections decreased the amplitude of Ins(2,4,5)P3-induced oscillations without altering their frequency. Injections of the Ins(1,4,5)P3 metabolite inositol 1,3,4,5-tetrakisphosphate also caused oscillations whose frequency was related to the injected dose, although inositol tetrakisphosphate injection induced an increase in the cellular level of Ins(1,4,5)P3. The results suggest a multicomponent oscillatory system that includes the InsP3 target as well as a Ca2(+)-sensitive step that modulates amplitude.
CN: AI20866AINIAID; HL42385HLNHLBI
Record 69 of 117 in MEDLINE(R)+ (1990-1992)
TI: Further characterization of the mouse sperm surface zona-binding site with galactosyltransferase activity.
AU: Benau,-D-A; McGuire,-E-J; Storey,-B-T
SO: Mol-Reprod-Dev. 1990 Apr; 25(4): 393-9
AB: One of the mouse sperm surface binding sites for zona pellucida ligands exhibits galactosyltransferase (GT) enzyme activity. The present study was undertaken to ascertain whether the GT site behaves as a noncatalytic binding site in its physiological capacity, with no glycosylation of zona ligands, or whether glycosylation of zona ligands is an integral part of sperm-zona binding. The effects of Mn2+, the obligatory cation for GT catalysis, on enzyme activity and sperm-zona binding were examined. With uridine-5'-diphosphogalactose (UDPgal) as galactose donor, and N-acetylglucosamine (GlcNAc) as galactose acceptor, increasing concentrations of Mn2+ in the range of 0.1-10 mM increased GT enzyme activity, with half-maximal activation at 0.65 mM Mn2+ (Vmax = 20 pmol/hr/10(6) cells). In the presence of 0-2 mM Mn2+, sperm-zona binding was inhibited in a concentration-dependent manner; 50% inhibition occurred at 1.25 mM Mn2+. At this concentration, GT enzyme activity was at 65% Vmax. To determine the specificity of the GT site for glycoprotein terminal carbohydrate residues, spermatozoa were incubated with, asialo-ovine submaxillary mucin (N-acetylgalactosamine residues), asialo-, -alpha 1-acid glycoprotein (beta 1-4 galactose residues) ovalbumin (Ov; GlcNAc residues), and asialo-agalacto-/alpha 1-acid glycoprotein (AsAgAGP; GlcN-Ac residues). Only Ov and AsAgAGP acted as acceptors for galactose in the enzyme assay and inhibitors in the sperm-zona binding assay. The kinetics of the interaction of AsAgAGP with the GT site were determined: the Km was 3.6 mg/ml, with Vmax of 33 pmol/hr/10(6) cells.(ABSTRACT TRUNCATED AT 250 WORDS)
CN: HD06274HDNICHD; HD06872HDNICHD
Record 70 of 117 in MEDLINE(R)+ (1990-1992)
TI: Calcium ions as a mediator in GnRH action on gonadotropin release in the common carp (Cyprinus carpio L).
AU: Mikolajczyk,-T; Weil,-C; Epler,-P; Breton,-B
SO: Reprod-Nutr-Dev. 1990; 30(4): 483-92
AB: Collagenase-dispersed carp pituitary cells in a perifusion system were used to study the role of calcium ions in the mechanism of GnRH action on the release of maturational gonadotropin (GtH) in fish. The specific calcium chelator EGTA and the calcium antagonist manganese (Mn2+) caused a 40% inhibition in the basal GtH release and completely blocked GnRH-stimulated GtH release. Short-term application of graded doses of calcium ionophore A23187 caused a dose-dependent increase in GtH secretion. A23187 failed to stimulate GtH secretion in the presence of EGTA. Depolarization of the membrane by K+ caused a strong stimulation of GtH release similar to the action of GnRH. Stimulatory action of K+ was inhibited by EGTA. These data suggest a role for extracellular calcium as an intracellular mediator in GnRH-stimulated, as well as in basal, GtH release in carp. The stimulation of GtH release by K+ also indicates that voltage-dependent processes could be involved in this phenomenon.
Record 71 of 117 in MEDLINE(R)+ (1990-1992)
TI: Progesterone and 17 alpha-hydroxyprogesterone. Novel stimulators of calcium influx in human sperm.
AU: Blackmore,-P-F; Beebe,-S-J; Danforth,-D-R; Alexander,-N
SO: J-Biol-Chem. 1990 Jan 25; 265(3): 1376-80
AB: Progesterone and 17 alpha-hydroxyprogesterone (but not other steroids such as testosterone, corticosterone, beta-estradiol, estrone, dehydroepiandrosterone, 20 alpha-hydroxypregnen-3-one, androstenedione, and pregnenolone) were shown to cause an immediate increase, in free cytosolic calcium ([Ca2+]i) in both capacitated and noncapacitated human sperm, using the fluorescent indicator fura 2. Significant increases in [Ca2+]i were observed with 10 ng/ml progesterone, while maximum effects were seen with 1 microgram/ml progesterone. Two other steroids 11 beta-hydroxyprogesterone and 5 alpha-pregnane-3,20-dione exhibited significant activity to increase [Ca2+]i. This increase in [Ca2+]i elicited by progesterone was entirely due to Ca2+ influx from the extracellular medium since the increase in [Ca2+]i was blocked by the Ca2+ chelator EGTA (2.5 mM) and the Ca2+ channel antagonist La3+ (0.25 mM) when added to the medium containing 2.5 mM Ca2+. Progesterone also stimulated the uptake of Mn2+ into sperm as measured by the quenching of fura 2 fluorescence. Progesterone has been found in human follicular fluid at levels capable of stimulating increases in [Ca2+]i. The similarities in responses induced by human follicular fluid and progesterone an increase in [Ca2+]i, and hence the acrosome reaction, is progesterone and/or 17 alpha-hydroxyprogesterone. Progesterone (1 microgram/ml) did not increase [Ca2+]i in somatic cells such as adipocytes, hepatocytes, Balb/c 3T3 cells, normal rat kidney, or DDT1 MF-2 cells. The effects of these progestins to increase [Ca2+]i, by activating a receptor-operated calcium channel, is the first report of such an activity in sperm. This phenomena possibly opens up a new field of steroid action in the area of sterility, fertility, and contraception at the level of the sperm.
Record 72 of 117 in MEDLINE(R)+ (1987-1989)
TI: The role of trace elements in male infertility.
AU: Abou-Shakra,-F-R; Ward,-N-I; Everard,-D-M
SO: Fertil-Steril. 1989 Aug; 52(2): 307-10
AB: The elemental status of seminal plasma collected from four populations subdivided on the basis of sperm counts is presented. Elemental analysis was performed by inductively coupled plasma-source mass spectrometry (ICP-MS) for calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, nickel, lead, rubidium, selenium, vanadium, and zinc. The majority of elements reflected no statistically significant differences among the four groups. The role of trace elements in infertility may be more directly related to sperm and whole semen than seminal plasma levels.
Record 73 of 117 in MEDLINE(R)+ (1987-1989)
TI: Mineral elements in unrefined sugar, and rat reproduction.
AU: Eisa,-O; Yudkin,-J
SO: Int-J-Vitam-Nutr-Res. 1989; 59(1): 77-9
AB: Male and female Sprague-Dawley rats were fed purified diets in which the carbohydrate component was either starch or refined sugar (sucrose). The addition to these diets of the ash prepared by the incineration of unrefined muscovado sugar prevented the deficiencies of Factor R seen in the offspring when the diets were not supplemented with ash. Analysis by neutron activation showed that the ash from the unrefined sugar significantly increased the proportion of iron, cobalt, manganese, caesium and rubidium in the diets. The addition of chlorides of all five mineral elements to the diet containing refined sugar also prevented the development of signs of deficiency of Factor R in the pups. However the addition of cobalt chloride alone, or of cobalt and manganese chlorides, did not prevent the deficiency. It is likely that what we have called reproductive Factor R is iron, caesium or rubidium.
Record 74 of 117 in MEDLINE(R)+ (1987-1989)
TI: Concentration of selected metals in normal and pathological human seminal plasma.
AU: Lafond,-J-L; Sele,-B; Favier,-A
SO: J-Trace-Elem-Electrolytes-Health-Dis. 1988 Mar; 2(1): 19-21
AB: The levels of zinc, ultrafilterable (UF) zinc, copper and manganese in normal and pathological (astheno-, azoo-, oligospermic) seminal plasma were measured by flameless atomic absorption. For ultrafiltrable zinc, a special method was used to treat Amikon membranes. A lower ultrafiltrable zinc level was found in azoospermic and a lower manganese level in oligospermic seminal plasma. At this time the meaning of these results is unknown.
Record 75 of 117 in MEDLINE(R)+ (1987-1989)
TI: Studies of the mechanism of action of gossypol as a male antifertility agent.
AU: White,-I-G; Vishwanath,-R; Swan,-M-A; Brown-Woodman,-P-D
SO: Contraception. 1988 Mar; 37(3): 269-77
AB: Gossypol administered orally to male rats at a daily dose of 20 mg/kg body weight for 62 days caused infertility. There were changes in the epididymal epithelium and the sperm were severely damaged and immotile. The sperm head was often detached; other defects were abnormal mitochondria, absence of plasma membranes and axonemal and accessory fibres and a lower oxygen uptake. To study the effect of gossypol on the motor apparatus of sperm, ram sperm were demembranated with the detergent, Triton-X-100. Such sperm models can normally be reactivated with ATP but gossypol (2.5-12.5 microM) decreased reactivation and must have a direct effect on the axoneme. Gossypol also inhibited ram sperm adenyl cyclase which is essential for maintaining high levels of cAMP in sperm and, in turn, motility. Ram sperm adenyl cyclase required Mn2+ for activity and high Mn2+ concentrations protected the enzyme from gossypol inhibition. Electron spin resonance studies proved that gossypol chelated Mn2+ with the formation of a 2:1 complex.
Record 76 of 117 in MEDLINE(R)+ (1987-1989)
TI: Cationic modulation of follicle-stimulating hormone binding to granulosa cell receptor.
AU: Ford,-K-A; LaBarbera,-A-R
SO: Biol-Reprod. 1987 Apr; 36(3): 643-50
AB: Magnesium (Mg2+) increases binding of follicle-stimulating hormone (FSH) to membrane-bound receptors and increases adenylyl cyclase activity. We examined the effects of divalent and monovalent cations on FSH binding to receptors in granulosa cells from immature porcine follicles. Divalent and monovalent cations increased binding of [125I]iodo-porcine FSH (125I-pFSH). The divalent cations Mg2+, calcium (Ca2+) and manganese, (Mn2+) increased specific binding a maximum of 4- to 5-fold at added concentrations of 10 mM. Mg2+ caused a half-maximal enhancement of binding at 0.6 mM, whereas Ca2+ and Mn2+ had half-maximal effects at 0.7 mM and 0.8 mM, respectively. The monovalent cation potassium (K+) increased binding a maximum of 1.5-fold at an added concentration of 50 mM, whereas the monovalent cation (Na+) did not increase binding at any concentration tested. The difference between K+ and Na+ suggested that either enhancement of binding was not a simple ionic effect or Na+ has a negative effect that suppresses its positive effect. Ethylenediamine tetraacetic acid, a chelator of Mg2+, prevented binding of 125I-pFSH only in the presence of Mg2+, whereas pregnant mare's serum gonadotropin, a competitor with FSH for the receptor, prevented binding in both the absence and the presence of Mg2+. Guanyl-5-ylimidodiphosphate (Gpp[NH]p) inhibited binding of 125I-pFSH in the absence or presence of Mg2+, but only at Gpp(NH)p concentrations greater than 1 mM. We used Mg2+ to determine if divalent cations enhanced FSH binding by increasing receptor affinity or by increasing the apparent number of binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)
CN: HD11021HDNICHD; HD16912HDNICHD
Record 77 of 117 in MEDLINE(R)+ (1987-1989)
TI: Divergent effects of cations on follicle-stimulating hormone- and forskolin-activated adenylyl cyclase in granulosa cells.
AU: Ford,-K-A; Hunzicker-Dunn,-M; LaBarbera,-A-R
SO: Biol-Reprod. 1987 Apr; 36(3): 651-7
AB: The divalent cations magnesium, calcium and manganese, and the monovalent cation, potassium, but not sodium, enhance binding of [125I]iodo-porcine follicle-stimulating hormone to follicle-stimulating hormone (FSH) receptors in membranes of porcine granulosa cells via an increase in the apparent number of binding sites. The objective of the present studies was to determine if increased binding of FSH to its receptor causes increased adenylyl cyclase activity in response to FSH, or conversely, if enhancement of the cyclase or one of its components causes increased binding, or if the two processes are modulated independently. MgCl2 and CaCl2, which both enhance binding in intact cells and in cell-free membrane preparations, had opposite effects on cyclase-MgCl2 stimulatory, CaCl2 inhibitory. In isotonic NaCl, MgCl2 did not enhance binding, but it did increase FSH-stimulated production of cyclic adenosine 3',5'-monophosphate (cAMP). NaCl did not enhance FSH binding and it did not enhance cyclase in cell-free membranes, but it did increase FSH- and forskolin-stimulated cAMP production in intact cells. In intact cells, maximally effective concentrations of MgCl2 and KCl were additive in enhancing cAMP production whereas the effects of NaCl and KCl together were synergistic. The results indicate that although cationic effects on FSH binding are not causally related to effects on cyclase, the cationic microenvironment of the granulosa cell membrane is critical to both FSH receptor and adenylyl cyclase functions.
CN: HD11021HDNICHD; HD11356HDNICHD; HD16912HDNICHD
Record 78 of 117 in MEDLINE(R)+ (1987-1989)
TI: Stimulation of partially purified adenylate cyclase from bull sperm by bicarbonate.
AU: Garty,-N-B; Salomon,-Y
SO: FEBS-Lett. 1987 Jun 22; 218(1): 148-52
AB: Solubilized and partially purified adenylate cyclase from bull sperm was found to be specifically activated (up to 6-fold) by sodium bicarbonate (NaHCO3) and to a lesser extent by NaNO3. Other sodium salts were either ineffective (e.g. NaCOOH) or inhibitory (e.g. NaHSO3, NaHSO4 and Na2B4O7). Stimulation by NaHCO3 was dose-dependent in the range of 0-40 mM and was greater when enzyme activity was assayed in the presence of magnesium as compared with manganese ions. Bicarbonate seems to affect maximal enzyme velocity (Vmax) and has no effect on the Km of adenylate cyclase for Mn-ATP. Stimulation of adenylate cyclase by NaHCO3 coincided with the elution pattern of the enzyme as recorded following chromatography on DEAE-cellulose or gel filtration on BioGel P-100. These results suggest that in the course of stimulation of sperm adenylate cyclase, bicarbonate is likely to interact directly with the enzyme. Furthermore, this intrinsic and unique property of sperm adenylate cyclase may explain results reported by others on the stimulation of cAMP production by bicarbonate in intact and broken sperm preparations and suggest a biochemical basis for enhanced sperm motility associated with high bicarbonate concentrations.
Record 79 of 117 in MEDLINE(R)+ (1987-1989)
TI: Reproductive toxicology of manganese in rodents, including exposure during the postnatal period.
AU: Webster,-W-S; Valois,-A-A
SO: Neurotoxicology. 1987 Fall; 8(3): 437-44
Record 80 of 117 in MEDLINE(R)+ (1987-1989)
TI: Comparative studies of elemental composition on ejaculated fowl, bull, rat, dog and boar spermatozoa by electron probe X-ray microanalysis.
AU: Ashizawa,-K; Ozawa,-Y; Okauchi,-K
SO: Comp-Biochem-Physiol-A. 1987; 88(2): 269-72
JN: Comparative-biochemistry-and-physiology. Comparative-physiology
AB: 1. Comparative analyses of the concentrations of bulk and trace elements on the head, midpiece and tail regions of the ejaculated fowl, bull, rat, dog and boar spermatozoa were performed using X-ray microanalysis with scanning electron microscopy. 2. Although the pattern of distribution of elements on the surface of the three different subcellular regions was, in general, similar among all the species, there were substantial shifts in absolute concentrations. 3. Concentration of magnesium on the dog spermatozoa was significantly higher (about 2 times) than those of the other species. 4. Zinc, copper, iron and manganese concentrations were higher on fowl spermatozoa compared with those of the other species studied. 5. The Na-to-K ratios on the midpiece ranged from 1.46 (rat) to 2.26 (dog).
Record 81 of 117 in MEDLINE(R)+ (1981-1986)
TI: Manganese and manganese-ATP interactions with bovine sperm adenylate cyclase.
AU: Brown,-M-A; Casillas,-E-R
SO: Arch-Biochem-Biophys. 1986 Feb 1; 244(2): 719-26
AB: The adenylate cyclase of mammalian spermatozoa shares some of the properties of the isolated catalytic component from somatic cell adenylate cyclases. One of these properties is the large apparent stimulation by Mn2+. We have used the direct linear plot according to Eisenthal and Cornish-Bowden to explore whether this apparent stimulation is due to direct stimulation by Mn2+ or due to complexation of free ATP, a postulated inhibitor of cyclase activity. We have observed the activity of the particulate adenylate cyclase from bovine caudal epididymal spermatozoa as a function of calculated equilibrium values for the concentrations of Mn2+, free ATP, and the enzyme's substrate, the manganese-ATP complex. Direct linear plots for activity and substrate concentration over the apparent inhibitory concentration range of free ATP give the pattern expected for a hyperbolic substrate response. By contrast, direct linear plots in which Mn2+ concentration varies over its apparent stimulatory range show that as Mn2+ concentration increases, activities are higher than would be predicted for a hyperbolic substrate response. We conclude that for particulate bovine sperm adenylate cyclase, free ATP is not strongly inhibitory, and Mn2+ is a positive effector, reaching half-maximal stimulation at 0.2 mM. The unique nature of the sperm adenylate cyclase and its possible regulation by Mn2+ under physiological conditions is discussed.
CN: HD10664HDNICHD; RR08136RRNCRR
Record 82 of 117 in MEDLINE(R)+ (1981-1986)
TI: Inhibition of the catalytic subunit of ram sperm adenylate cyclase by adenosine.
AU: Henry,-D; Ferino,-F; Tomova,-S; Ferry,-N; Stengel,-D; Hanoune,-J
SO: Biochem-Biophys-Res-Commun. 1986 Jun 30; 137(3): 970-7
AB: Adenosine inhibits ram sperm adenylate cyclase activity which is membrane-bound and comprises only the catalytic subunit. The inhibition parameters of adenylate cyclase by adenosine were not modified when the enzyme was purified 3 to 5,000 fold. Optimal inhibition by adenosine was found to require a high concentration of manganese, and exhibited a noncompetitive pattern up to a concentration of 1 mM adenosine. Adenosine was the most potent inhibitor among various analogs tested with the following rank order of potencies: adenosine greater than 2'O-methyladenosine greater than 2'deoxyadenosine much greater than 2 chloroadenosine. Studies with agonists and antagonists of the "R"-type adenosine receptor led us to conclude that adenosine inhibits ram sperm adenylate cyclase via a "P"-site carried by the catalytic subunit itself.
Record 83 of 117 in MEDLINE(R)+ (1981-1986)
TI: Purification of the proteolytically solubilized, active catalytic subunit of adenylate cyclase from ram sperm. Inhibition by adenosine.
AU: Stengel,-D; Henry,-D; Tomova,-S; Borsodi,-A; Hanoune,-J
SO: Eur-J-Biochem. 1986 Nov 17; 161(1): 241-7
AB: Ram spermatozoa adenylate cyclase is insensitive to all usual regulatory processes. The purification of its active catalytic subunit was accomplished after proteolytic solubilization of a particulate fraction by alpha-chymotrypsin. The purification (26,000-fold from the particulate fraction or 125,000-fold from the whole-sperm proteins) was achieved by conventional procedures (DEAE-Trisacryl, Ultrogel AcA 34, DEAE-Sephacel, hydroxyapatite), in the absence of detergent, and with a yield of 5-10% and a final specific activity of 19 mumol cyclic AMP formed mg protein-1 min-1 at 30 degrees C in the presence of manganese as cosubstrate. The solubilized enzyme, stable at the beginning of the purification procedure, became unstable at the later stages. After the last step (chromatography on hydroxyapatite) half-lives of 27 min, 50 min and 160 min were obtained at 30 degrees C, 20 degrees C and 4 degrees C respectively. The enzyme was stabilized by addition of bovine serum albumin and Lubrol PX, 80% of the activity remaining after 24 h at 4 degrees C. The purified enzyme exhibited a Km value similar to that of the native enzyme (Km = 1.4 mM). Unlike the native enzyme, the purified enzyme has an absolute requirement for MnATP; no significant activity was recovered in the presence of MgATP. Adenosine inhibited the activity of both the native and purified forms of the enzyme to the same extent and in a non-competitive manner. This indicates that adenosine acts on the catalytic component itself and the inhibition site and the catalytic site are different. Data obtained with adenosine analogs indicate that adenosine interacts with the cyclase catalytic subunit with a 'P-site' specificity. The purified adenylate cyclase, which had an apparent molecular mass of 38 kDa on a high-performance liquid chromatography column [Stengel, D., Guenet, L. and Hanoune, J. (1982) J. Biol. Chem. 257, 10,818-10,826], gave a doublet of 36 kDa and 34 kDa on sodium dodecyl sulfate gel electrophoresis. This represents the smallest protein entity associated with adenylate cyclase activity so far reported.
Record 84 of 117 in MEDLINE(R)+ (1981-1986)
TI: ATP-induced reactivation of ram testicular, cauda epididymal, and ejaculated spermatozoa extracted with Triton X-100.
AU: White,-I-G; Voglmayr,-J-K
SO: Biol-Reprod. 1986 Feb; 34(1): 183-93
AB: It was possible to demembrante and reactivate not only freshly collected testicular, cauda epididymal, and ejaculated ram sperm but also sperm that had been stored for several days at 0 degrees C and for several months at -196 degrees C in rete testis fluid or egg yolk citrate media. Sperm were usually washed free of seminal plasma before demembranation, but this was not essential for reactivation. Bovine serum albumin (1.0%) in the wash medium increased the survival of sperm, but more than 0.25% in the extraction medium decreased reactivation. A macro-molecular component of cauda epididymal fluid also inhibited the reactivation of testicular sperm. Triton X-100 concentrations between 0.01% and 1.00% in the extraction medium were satisfactory for demembranating the sperm. Rapid cooling (i.e., cold shock) mimicked the effect of detergent in making the sperm responsive to added ATP and demonstrated that damage to ram sperm in cold shock does not involve the axoneme. Ejaculated and cauda sperm were reactivated immediately on addition of ATP and activity persisted for up to 10 min. Testicular sperm, on the other hand, required about 4 min to become fully reactivated. The optimal ATP concentration for activation of sperm was 0.1-1.0 mM. Magnesium ions (0.1-1.0 mM) were important for reactivation, and testicular sperm required a higher magnesium concentration than did cauda or ejaculated sperm. Manganese ions were almost as effective as magnesium for reactivating cauda epididymal and ejaculated sperm. Cobalt and cadmium ions were much less active for cauda and ejaculated sperm and none of these ions were effective for testicular sperm. Fluoride (25-50 mM) inhibited reactivation. The presence of 50 microM cAMP in the extraction medium or preincubation of testicular sperm with theophylline or caffeine increased low levels of activation, but this was not evident with ejaculated or cauda sperm. We conclude that the motor apparatus is already functionally assembled in spermatozoa on leaving the testis, but some fine adjustment must take place during maturation in the epididymis.
CN: HD09356HDNICHD; HD15272HDNICHD
Record 85 of 117 in MEDLINE(R)+ (1981-1986)
TI: Assessment of the male reproductive system in the preweanling rat following Mn3O4 exposure.
AU: Laskey,-J-W; Rehnberg,-G-L; Hein,-J-F; Laws,-S-C; Edens,-F-W
SO: J-Toxicol-Environ-Health. 1985; 15(2): 339-50
AB: Long-Evans rat pups were dosed orally from birth to 21 d with particulate Mn3O4 to obtain a daily dose of 0, 71, or 214 micrograms Mn/body weight . d. Assessments of the hypothalamic, pituitary, or testicular functions were determined by measuring the endogenous or stimulated serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and/or testosterone (T) at 21 or 28 d of age. Body, testes, and seminal vesicles weight and tissue concentrations of Mn were also evaluated. Only slight Mn treatment effects were seen in body and testes weights. No effects were seen either on unstimulated or stimulated FSH or LH serum concentrations. Although no Mn treatment effects were seen on endogenous or 2 h human chorionic gonadotropin (hCG) stimulate serum T concentrations, there was a reduction in the serum T following 7 d of hCG stimulation. The hypothalamic Mn concentrations in animals with these reproductive effects were three times those where alterations in the dopaminergic pathway have been reported. However, no indication of hypothalamic or pituitary malfunction was found. These results suggest that the site of Mn damage that causes depression of sustained serum T concentration is in the testicular Leydig cell.
Record 86 of 117 in MEDLINE(R)+ (1981-1986)
TI: Demonstration of galactosyltransferase activity in human seminal plasma and its relation to sperm penetration in cervical mucus.
AU: Ronquist,-G; Stegmayr,-B; Andren,-C; Wikstrom,-K
SO: Urol-Int. 1985; 40(5): 269-73
AB: The galactosyltransferase activity was determined in seminal plasma from 24 men with various sperm characteristics subdivided in three different groups and from 9 men subjected to vasectomy for the purpose of voluntary sterilization contributing a 4th group. The galactosyltransferase displayed an obligatory dependency on manganese ions for activity. Endogenous glycoproteins of human seminal plasma were poor acceptors for the galactosyltransferase reaction, and a more than 40-fold increase in activity was achieved in the presence of ovomucoid as exogenous acceptor. There were no significant intergroup differences with regard to galactosyltransferase activity. Hence, qualitative and quantitative discrepancies of spermatozoa were not influential on galactosyltransferase activity in a decisive way. An overall positive correlation was registered between galactosyltransferase activity and sperm penetration in cervical mucus (r = 0.53; p less than 0.01).
Record 87 of 117 in MEDLINE(R)+ (1981-1986)
TI: Forskolin stimulates bovine epididymal sperm motility and cyclic AMP levels.
AU: Vijayaraghavan,-S; Hoskins,-D-D
SO: J-Cyclic-Nucleotide-Protein-Phosphor-Res. 1985; 10(5): 499-510
AB: Forskolin, a diterpene, has been reported to reversibly stimulate adenylate cyclase from a number of mammalian tissues. Adenylate cyclase preparations derived from sperm are reported to be both deficient in the guanine nucleotide subunit and insensitive to forskolin. Despite the latter observation, we report here that forskolin elevates cAMP levels in immature caput sperm, and initiates motility in the presence of "permissive" agents such as bicarbonate, procaine and dibucaine. In mature caudal sperm forskolin stimulates motility in a concentration dependent manner in the presence of the phosphodiesterase inhibitor IBMX but elevates cAMP levels only briefly before nucleotide levels return to control values. In addition, forskolin stimulates adenylate cyclase activity associated with plasma membrane preparations of caput sperm but not caudal sperm. This differential action of forskolin on these cell types could provide a basis for understanding the regulation of adenylate cyclase in both immature and mature bovine sperm.
CN: HD11982HDNICHD; RR0163RRNCRR
Record 88 of 117 in MEDLINE(R)+ (1981-1986)
TI: Manganese stimulates calcium flux through the mitochondrial uniporter.
AU: Allshire,-A; Bernardi,-P; Saris,-N-E
SO: Biochim-Biophys-Acta. 1985 May 3; 807(2): 202-9
AB: Mn2+ alters the balance between the simultaneous uptake and release of Ca2+ across the mitochondrial inner membrane toward a lower external level. Addition of as little as 0.5 microM Mn2+ to energised mitochondria from rat liver, rat heart or guinea-pig brain changed the level at which they buffered Ca2+ in the medium. That extramitochondrial Mn2+ was responsible was suggested by a partial decay in the shift in Ca2+ steady state at a rate similar to the rate at which Mn2+ was accumulated by the mitochondria. The alteration of transmembrane Ca2+ distribution by Mn2+ required that both Mg2+ and Pi be present, and was almost maximal at Mg2+ and Pi levels in the physiological range. Substitution of spermine or Ni2+ for Mg2+, or acetate for Pi, abolished the effect. In contrast to Sr2+, Mn2+ did not inhibit either EGTA- or Ruthenium red-induced release of Ca2+ from the mitochondria. However, when flux through the uniporter was rate-limiting, Mn2+ accelerated Ca2+ uptake. The stimulation showed hyperbolic kinetics, with an element of competition discernible in the Mn2+-Mg2+ interaction. Thus, extramitochondrial Mn2+ at levels occurring in vivo can alter the mitochondrial 'set-point' by stimulating Ca2+ influx through the uniporter.
Record 89 of 117 in MEDLINE(R)+ (1981-1986)
TI: Presence of several elements in normal and pathological human semen samples and its origin.
AU: Skandhan,-K-P; Abraham,-K-C
SO: Andrologia. 1984 Nov-Dec; 16(6): 587-8
AB: Spectroscopic analysis of seventeen normal and pathological semen samples was done to reveal the different elements present in it. The sensitivity of the instrument was 1 micrograms/g. The observed elements include sodium, potassium, magnesium, calcium, phosphorus, iron, manganese, zinc, copper, boron, silicon, thallium, vanadium, aluminium, mercury and gold. This is the richest source of gold reported in biological materials. An attempt was done to locate the origin of these elements. Thus gold is released from caput epididymis.
Record 90 of 117 in MEDLINE(R)+ (1981-1986)
TI: Bovine sperm adenylate cyclase. Inhibition by adenosine and adenosine analogs.
AU: Brown,-M-A; Casillas,-E-R
SO: J-Androl. 1984 Sep-Oct; 5(5): 361-8
AB: Since both adenosine and cAMP affect sperm motility and metabolism, the authors have studied the mode of interaction of adenosine with the adenylate cyclase activity in either the presence or the absence of 15 mM caffeine. In general, structural analogs of adenosine containing alterations of the purine structure produce little or no inhibition, whereas analogs containing alterations of the ribose structure are effective inhibitors. Cyclic AMP and caffeine also inhibit the enzyme activity. The kinetics of the adenosine inhibition most closely resemble the linear noncompetitive type. Adenosine is a more effective inhibitor of adenylate cyclase activity in the presence of Mn2+ rather than Mg2+, and is more effective at higher metal ion concentrations. These observations are consistent with a P-site interaction of adenosine with adenylate cyclase.
CN: HD10664HDNICHD; RR08136RRNCRR
Record 91 of 117 in MEDLINE(R)+ (1981-1986)
TI: Slowly inactivating potassium channels induced in Xenopus oocytes by messenger ribonucleic acid from Torpedo brain.
AU: Gundersen,-C-B; Miledi,-R; Parker,-I
SO: J-Physiol. 1984 Aug; 353231-48
AB: Poly(A+) messenger RNA was extracted from the electric lobe and medulla of Torpedo and injected into oocytes of Xenopus laevis. The synthesis and processing of proteins coded by the injected messenger RNA led to the incorporation of voltage-activated channels in the oocyte membrane. A large, well maintained outward current was recorded from injected oocytes in response to depolarization. Non-injected oocytes did not show this current. The reversal potential of the current varied according to the Nernst equation with external potassium concentration, indicating that it was largely carried by potassium ions. The maintained potassium current was not reduced by manganese (5 mM) or lanthanum ions (0.1 mM). Tetraethylammonium and aminopyridines blocked the potassium current. The block produced by 3,4-diaminopyridine was enhanced by previous activation, but diminished by strong depolarization. The amplitude of the potassium current increased over the approximate voltage range -30 to +50 mV, but reduced at more positive potentials. The decline of the current during maintained depolarization became slower as the membrane potential was made more positive, and the rate of onset of the current became faster. Estimates from noise analysis indicated that the slow potassium current passes through channels with a mean lifetime of about 14 ms and conductance of 14 pS (at -10 mV and room temperature). Injection of the messenger RNA also induced the formation of fast sodium and potassium channels activated by voltage, and channels activated by kainate.
Record 92 of 117 in MEDLINE(R)+ (1981-1986)
TI: Effects of the calcium-channel blockers cobalt, verapamil, and D600 on Leydig cell steroidogenesis.
SO: Biol-Reprod. 1983 Apr; 28(3): 528-35
AB: The effects of various calcium-channel blockers on androgen production by collagenase-dispersed mouse testicular interstitial cells were investigated. Cobalt caused a dose-dependent inhibition of the maximum rate of luteinizing hormone (LH)-stimulated androgen production without altering the concentration of LH required for half maximum stimulation (EC50). Nickel and manganese also inhibited LH-stimulated steroidogenesis but were less potent than cobalt. The major site at which cobalt treatment inhibited steroidogenesis was beyond cAMP formation and before 3 beta-hydroxysteroid dehydrogenase. This conclusion was based on the observation that cobalt inhibited dibutyryl cAMP-stimulated androgen production but did not affect protein synthesis and pregnenolone-supported androgen production. Androgen production was unaffected by the organic calcium-channel blockers verapamil and the (+) and (-) enantiomers of D600 at concentrations less than 0.1 mM. At a concentration of 0.1 mM the organic calcium-channel blockers inhibited LH- and dibutyryl cAMP-stimulated androgen production. Unlike cobalt, the organic calcium-channel blockers also inhibited pregnenolone-supported androgen production and reduced the rate of protein synthesis. Similarities between the effects of cobalt in the present study and previous reports of the effects of reduced extracellular calcium concentrations on androgen production suggest that cobalt inhibits androgen production as a result of its ability to block calcium influx. The calcium channels involved in the steroidogenic process appear, however, to be relatively insensitive to the organic calcium-channel blockers.
Record 93 of 117 in MEDLINE(R)+ (1981-1986)
TI: Changes induced by manganese in fish testis.
AU: Srivastava,-A-K; Agrawal,-S-J
SO: Experientia. 1983 Nov 15; 39(11): 1309-10
AB: Exposure of Colisa fasciatus, a freshwater teleost, to 2500 mg/l manganese sulphate for 90 h caused decreased spermatogenic activity and hemorrhage in the testes.
Record 94 of 117 in MEDLINE(R)+ (1981-1986)
TI: Cyclic nucleotide phosphodiesterase activity in midpiece and tail of buffalo spermatozoa and its role in sperm motility.
AU: Bhatnagar,-S-K; Anand,-S-R
SO: Biochim-Biophys-Acta. 1982 May 27; 716(2): 133-9
Record 95 of 117 in MEDLINE(R)+ (1981-1986)
TI: Stage dependent variation in Mn2+-sensitive adenylyl cyclase (AC) activity in spermatids and FSH-sensitive AC in sertoli cells.
AU: Gordeladze,-J-O; Parvinen,-M; Clausen,-O-P; Hansson,-V
SO: Arch-Androl. 1982 Feb; 8(1): 43-51
AB: The variation of the specific Mn2+-dependent adenylyl cyclase (AC activity in spermatids and follicle stimulating hormone (FSH)-responsive AC activities in Sertoli cells in different stages (I-XIV) of the seminiferous epithelial cycle has been investigated. Maximal Mn2+-dependent AC activity was observed in stages II-III while minimal activity was encountered in stages VII-VIII (spermiation). FSH-responsive AC activity exhibited a pattern that coincided with that of the Mn2+-dependent AC. The stage-dependent variation in spermatid AC activity cannot be explained by altered numbers of haploid cells. This raises the question whether the Sertoli cells may regulate the spermatid AC activity. Sertoli cells in various stages are all exposed to the same concentration of circulatory hormones. Hence the stage-dependent difference in FSH-responsiveness indicates that local influences (from germ cells?) may regulate the response of the AC in Sertoli cells to FSH.
Record 96 of 117 in MEDLINE(R)+ (1981-1986)
TI: Involvement of dolichol phosphates as intermediates in the mannosyl and galactosyl transferases of rat testicular germ cell Golgi apparatus membranes.
AU: Flanagan,-K; Scouten,-W-H; Nyquist,-S-E
SO: Biol-Reprod. 1982 Feb; 26(1): 147-54
AB: Isolated Golgi apparatus membranes from the germinal elements (spermatocytes and early spermatids) of rat testis were examined for their ability to incorporate [14C]mannose and [14C]galactose into glycolipid and glycoprotein fractions. Transfer of mannose from GDP-[14C]mannose into a Lipid I fractions (GPD:MPP mannosyl transferase activity), identified as mannosyl phosphoryl dolichol, showed optimal activity at 1.5 mM manganese and at pH 7.5. Low concentrations of Triton X-100 (0.1%) stimulated transferase activity in the presence of exogenous dolichol phosphate (Dol-P); however, inhibition occurred at Triton X-100 concentrations greater than 0.1%. Maximal activity of this GDP:MPP mannosyl transferase occurred at 25 microM Dol-P. Activity using endogenous acceptor was 2.34 pmole/min/mg, whereas in the presence of 25 microM Dol-P the specific activity was 284 pmole/min/mg, a stimulation of 125-fold. Incorporation of mannose into a Lipid II (oligosaccharide pyrophosphoryl dolichol) and a glycoprotein fraction was also examined. In the absence of exogenous Dol-P, rapid incorporation into Lipid I occurred with a subsequent rise in Lipid II and glycoprotein fractions suggesting precursor-product relationships. Addition of exogenous Dol-P to galactosyl transferase assays showed only a minor stimulation, less than twofold, in all fractions. Over the concentration range of 9.4 to 62.5 micrograms/ml Dol-P, only 1% of radioactive product accumulated in the combined lipid fractions. These observations suggest that the mannose transfer involves Dol-P intermediates and also that spermatocyte Golgi membranes may be involved in formation of the oligosaccharide core as well as in terminal glycosylations.
Record 97 of 117 in MEDLINE(R)+ (1981-1986)
TI: Cellular localization of the Mn2+-dependent adenylyl cyclase in the human testis.
AU: Gordeladze,-J-O; Abyholm,-T; Cusan,-L; Clausen,-O-P; Hansson,-V
SO: Arch-Androl. 1982 May; 8(3): 199-204
AB: An examination of the activity of the Mn2+-dependent adenylyl cyclase (AC) in fine needle biopsies from human testes was made. Simultaneously the DNA distribution patterns in suspensions of testicular cells derived from the same patients have been determined. The DNA distribution patterns were estimated by microflow fluorimetry (MFF) after straining with fluorochrome (ethidium bromide). Thus, AC activity could be assessed and correlated with the relative number of haploid (1C = spermatids), diploid (2C = spermatogonia and testicular somatic cells), and tetraploid (4C = primary spermatocytes) cells. Testicular Mn2+-dependent AC activities varied between 0 and 8.4 pmol cyclic adenosine monophosphate (cAMP)/mg protein/min and were highly correlated with the contents of haploid (1C) germ cells (spermatids) (r = 0.62, p less than 0.01). There was no correlation between Mn2+-dependent AC activity and diploid or tetraploid cells. This indicates that the Mn2+-dependent AC activity in the human testis, like in the rat and mouse, may be exclusively localized to haploid germ cells. An inverse correlation between plasma FSH and Mn2+-dependent AC activities indicated reduced inhibin secretion in situations where the Sertoli cells did not maintain the testicular germ cell production.
Record 98 of 117 in MEDLINE(R)+ (1981-1986)
TI: Partial characterization of human spermatozoal phosphodiesterase and adenylate cyclase and the effect of steroids on their activities.
AU: Cheng,-C-Y; Boettcher,-B
SO: Int-J-Androl. 1982 Jun; 5(3): 253-66
AB: In sonicated human spermatozoa, phosphodiesterase hydrolyzed adenosine 3':5'-monophosphate (cAMP) at 20.80 +/- 3.23 nmoles/10(8)sperm/20 min at 37 degrees C (50 microM cAMP, initially). In human semen, about 60% of the phosphodiesterase activity was in the spermatozoa. Both polyacrylamide gel electrophoresis and DEAE-cellulose column chromatography indicated that there are at least 5 isozymes of phosphodiesterase. Various steroids were tested at a concentration of 2 micrograms/ml for their effects on phosphodiesterase activity in semen. None was found to have any significant effect. In sonicated human spermatozoa, adenylate cyclase synthesized cAMP at 0.02-2.11 nmoles/10(8)sperm/20 min at 37 degrees C (1 mM ATP, initially) depending on the availability of Mn2+ and caffeine in the assay mixture. Mn2+ was demonstrated to be a potent adenylate cyclase activator in human spermatozoa and its effect on human sperm adenylate cyclase was found to be dose-dependent. Cholera toxin, at a concentration of 20 micrograms/ml, had no effect on human sperm adenylate cyclase activity after it had been incubated with the intact spermatozoa for between 5 min and 5 h at 37 degrees C before the sperm were homogenized and the rate of cAMP formation assayed. In addition, human sperm adenylate cyclase decayed rapidly at 37 degrees C. Of various steroids tested at a concentration of 2 micrograms/ml for their effects on human sperm adenylate cyclase activity, only oestradiol-17 beta showed a significant effect, elevating the rate of cAMP formation by about 30%.
Record 99 of 117 in MEDLINE(R)+ (1981-1986)
TI: Effect of cAMP, Mn2+, and phosphodiesterase inhibitors on human sperm motility.
AU: Cheng,-C-Y; Boettcher,-B
SO: Arch-Androl. 1981 Dec; 7(4): 313-7
AB: The effects of cyclic adenosine monophosphate (cAMP), MnCl2, caffeine, and theophylline at concentrations of 10 mM on human sperm motility and forward migration in vitro were tested. cAMP was effective in activating human spermatozoal motility and forward migration after incubation with the spermatozoa for 3 hr or more and 5 hr, respectively, whereas caffeine and theophylline were effective in activating sperm motility after incubation with the spermatozoa for 1 hr or more. Caffeine and theophylline significantly activated sperm forward migration only after incubation with the sperm for 5 hr. MnCl2, a potent sperm adenylate cyclase activator, had no significant effect in improving human sperm motility and forward migration.
Record 100 of 117 in MEDLINE(R)+ (1975-1980)
TI: Multivariate analysis of the effects of manganese on the reproductive physiology and behavior of the male house mouse.
AU: Gray,-L-e; Laskey,-J-W
SO: J-Toxicol-Environ-Health. 1980 Jul; 6(4): 861-7
AB: Chronic exposure to Mn3O4 in the diet at 1050 ppm Mn retarded the sexual development and lowered reactive locomotor activity levels in male mice. A multivariate analysis of variance indicated that testis, seminal vesicle, and preputial gland weights were significantly smaller as a result of Mn administration. These results support earlier observations of altered locomotor activity levels and reproductive development in male rats in the absence of other signs of toxicity.
Record 101 of 117 in MEDLINE(R)+ (1975-1980)
TI: Isolation and properties of superoxide dismutase from bovine spermatozoa.
AU: Magnes,-L-J; Li,-T-K
SO: Biol-Reprod. 1980 May; 22(4): 965-9
Record 102 of 117 in MEDLINE(R)+ (1975-1980)
TI: New antifertility agents active in the rabbit vaginal contraception (RVC) method.
SO: Contraception. 1980 Dec; 22(6): 659-72
AB: Zinc salts in aqueous K-Y Jelly are effective vaginal contraceptives in the rabbit. The minimum effective dose is 54 to 60 mg Zn/ rabbit as acetate, gluconate or lactate. Zinc salts added to suboptimal doses of Ortho-Gynol Jelly or Delfen Cream improves the vaginal contraceptive efficacy of these products. Twenty-seven mg zinc/rabbit as lactate or acetate and 28 mg zinc/rabbit as sulfate or chloride in 0.1 to 0.5 ml of cream or jelly are effective. Gossypol is effective at a dose of 2 mg/rabbit. Although there is some rationale for their use, manganese has no antifertility effect and valium appears to promote fertility. The rabbit vaginal contraception (RVC) method shows undesirable variation but use of sufficient animals yields logical and reliable results. Artificial insemination instead of breeding appears to decrease variation.
Record 103 of 117 in MEDLINE(R)+ (1975-1980)
TI: Particulate and soluble adenylate cyclase activities of mouse male germ cells.
AU: Adamo,-S; Conti,-M; Geremia,-R; Monesi,-V
SO: Biochem-Biophys-Res-Commun. 1980 Nov 28; 97(2): 607-13
Record 104 of 117 in MEDLINE(R)+ (1975-1980)
TI: Apparent effect of ascorbic acid medication on semen metal levels.
AU: Harris,-W-A; Harden,-T-E; Dawson,-E-B
SO: Fertil-Steril. 1979 Oct; 32(4): 455-9
AB: The apparent effect of ascorbic acid therapy for nonspecific spermagglutination on semen levels of ascorbic acid as well as macro- and micrometals was determined in 20 men (ages 25 to 38). Pretreatment diagnosis was based on infertility and relatively low ratings in sperm density, motility, motility index, and semen volume, and were associated with large numbers of abnormal sperm, sperm precursors, and leukocytes. The pretreatment levels of ascorbic acid, sodium, iron, potassium, zinc, manganese, lead, magnesium, and copper were measured in each patient's semen and compared with levels following 60 days of dietary vitamin C supplementation (1.0 gm/day). Analysis of the vitamin C preparation prescribed revealed that each subject was given an impure ascorbic acid medication to supplement a normal diet. Therefore, the significant increases in levels of ascorbic acid and metals in semen following therapy could not be attributed to ascorbic acid alone, nor, similarly, the improved physical parameters of each subject's semen following therapy; no apparent spermagglutination and restored fertility may be due to the interaction of ascorbic acid with cations found in semen.
Record 105 of 117 in MEDLINE(R)+ (1975-1980)
TI: Trace element deficiencies and fertility in ruminants: a review.
SO: J-Dairy-Sci. 1979 Aug; 62(8): 1195-206
AB: Various minerals (copper, cobalt, selenium, manganese, iodine, zinc, and iron) can influence reproductive performance of ruminants. Reproductive failure may be induced by deficiencies of single or combined trace elements and by imbalances. This review is focused on maladjustments of trace elements leading to impaired breeding performance. Opinion is diverse as to the existence of various reproductive disturbances from either a severe copper depletion or a marginal dietary copper deficiency. Field experience suggests that administration of cobalt to ruminants on cobalt-deficient diets improves their impaired breeding performance. Selenium infertility in ewes is more prevalent in some areas and in some seasons, but the actual cause of this malady and the continuing role of additional factors are unknown. Manganese is necessary for normal fertility in ruminants, and feeding low-manganese rations depresses conception rates. Lack of iodine impairs thyroid activity and also ovarian function. Reproductive failure in the female and in spermatogenesis are manifestations of zinc deficiency. Despite forages rich in iron, low availability in certain instances could affect adversely ruminant reproduction. Knowledge of biochemical dysfunctions from trace element deficiencies is essential to determine the role which trace elements play in fertility of ruminant animals.
Record 106 of 117 in MEDLINE(R)+ (1975-1980)
TI: Ionic requirements of impaled bull spermatozoa driven by external ADP and ATP.
AU: Rikmenspoel,-R; Orris,-S-E; O'Day,-P-M
SO: Exp-Cell-Res. 1978 Feb; 111(2): 253-9
Record 107 of 117 in MEDLINE(R)+ (1975-1980)
TI: The involvement of calcium in the activation of mammalian oocytes.
AU: Whittingham,-D-G; Siracusa,-G
SO: Exp-Cell-Res. 1978 May; 113(2): 311-7
AB: Mouse oocytes with cumulus cells intact were parthenogenetically activated following release from the oviduct into calcium-free medium. The proportion of activated oocytes increased with post ovulatory age both for oocytes initially exposed to calcium-free and calcium-containing medium (control). Apart from oocytes released shortly after ovulation (approximately 1 h) when less than 1% of the oocytes from treated and control were activated, activation was always higher in oocytes incubated in calcium-free medium (p less than 0.001). The omission of magnesium from the medium had no effect on the activation response of oocytes obtained approximately 3 h after ovulation but its absence did increase the activation rate of oocytes of later post ovulatory age (approximately 9 h after ovulation) although it was still lower than that obtained with media devoid of calcium. When the extracellular calcium was replaced by other divalent cations (strontium, barium and manganese) high rates of activation were obtained even at post ovulatory times which produced relatively low rates of activation in calcium-free medium alone. Similar results were obtained when hamster oocytes were exposed to all the aforementioned treatments. It is concluded that calcium plays an essential role in the activation of the mammalian oocyte but the mechanism of its action remains obscure. Further development of oocytes activated by calcium-free treatment was limited and was similar to that of oocytes activated in other ways.
Record 108 of 117 in MEDLINE(R)+ (1975-1980)
TI: Mn2+-sensitive, soluble adenylate cyclase in rat testis. Differentiation from other testicular nucleotide cyclases.
AU: Braun,-T; Frank,-H; Dods,-R; Sepsenwol,-S
SO: Biochim-Biophys-Acta. 1977 Mar 15; 481(1): 227-35
AB: In subcellular fractions prepared from homogenate of adult rat testis adenylate cyclase (ATP pyrophosphate-lyase (cyclizing), EC 188.8.131.52) activity was found in the particulate, primarily 600 X g for 10 min, fractions, as well as in the cytosol. The properties of the adenylate cyclase in the cytosol differs substantially from the adenylate cyclase system associated with the 600 X g for 10 min particulate fraction. The cytosol enzyme, in contrast to the particulate adenylate cyclase, was found to be fluoride- and gonadotropin hormone-insensitive. The cytosol adenylate cyclase appears to be located in the germ cell while the particulate enzyme system in the non-germ cell component of the seminiferous tubules, The cytosol adenylate cyclase was found to be distinct also from the guanylate cyclase present in the rat testis cytosol. The adenylate cyclase appears to be located in the germ cell component while the guanylate cyclase, in the non-germ cell tubular component. Furthermore, it was found that the cytosol guanylate cyclase develops at an earlier stage of spermatogenesis, and precedes the development of the cytosol adenylate cyclase.
Record 109 of 117 in MEDLINE(R)+ (1975-1980)
TI: Ionic currents through the membrane of the mammalian oocyte and their comparison with those in the tunicate and sea urchin.
AU: Okamoto,-H; Takahashi,-K; Yamashita,-N
SO: J-Physiol. 1977 May; 267(2): 465-95
AB: 1. The action potential and the membrane current of the mouse oocyte were analysed by current-clamp and voltage-clamp techniques and they were compared with those of other animal oocytes. 2. The matured and unfertilized oocyte of the mouse in standard medium with 6 mM-K showed the resting potential of -23-1+/-2-9 mV. The resting potential was relatively large in the medium with 20 mM-Ca or 10 mM-Mn, being -35-7+/-2-6 mV and further increased to -46-9+/-4-8 mV with replacement of Na in the medium by choline. 3. At the cessation of large hyperpolarization below -90 mV in standard medium, a regenerative potential was often elicited in the form of an off-response. The off-response depended upon the external concentration of Ca. In 20 mM-Ca medium it was constantly observed with hyperpolarization below -60 mV. Its critical level was -40 mV and its overshoot was +15 mV. 4. The time and potential-dependent inward current was observed both in standard and 20 mM-Ca media under voltage-clamp condition. In 20 mM-Ca medium the inward current was observed by depolarization beyond -40 mV and showed its maximum at -15 mV. It was greatly reduced by replacing the external Ca with Mn but retained by substituting Sr or Ba for Ca. The selectivity ratios among these alkali earth cations were Ca:Sr:Ba=1-0:1-4:0-7. 5. The current-voltage relation in Ca and Na-deficient and 10 mM-Mn medium was linear from -200 to +25 mV. The hyperpolarization below -200 mV revealed an inward-going rectification. The depolarization above +50 mV under voltage-clamp condition induced the outward surge current with activation and inactivation processes. 6. In contrast to the mouse oocyte, the matured and unfertilized oocyte of the sea urchin showed a large resting potential of -70 mV in 30 Ca ASW and the depolarization beyond -40 mV elicited an action potential with an overshoot of 20 mV. The action potential showed a notch in the rising phase and lasted about 1 to 2 sec. 7. Under the voltage-clamp condition both Ca inward current and the outward surge current were observed in the sea urchin oocyte membrane just as in the mouse oocyte membrane. 8. The selectivity ratios among alkali earth cations, Ca:Sr:Ba, for 'Ca channels' of the oocyte membranes were 1-0:1-4:0-7 in the mouse, 1-0:1-7:1-1 in the tunicate and 1-0:0-7:0-5 in the sea urchin. When the current density through Ca channels are revised in terms of the respective critical levels for Ca channels, the revised selectivity sequences become Ca greater than Sr greater than Ba, being common to all three species.
Record 110 of 117 in MEDLINE(R)+ (1975-1980)
TI: Concentration of manganese in the tissues of cycling and anestrous ewes.
AU: Hidiroglou,-M; Shearer,-D-A
SO: Can-J-Comp-Med. 1976 Jul; 40(3): 306-9
AB: A wide range of variation in concentration of manganese was found in the blood of 51 cycling ewes although no significant differences were evident (P less than 0.05) between days 4, 11 and 15 (day 0 = day of estrus) of the estrous cycle. In addition, no differences (P less than 0.05) were found in the manganese concentrations of various soft tissues of 15 ewes, killed on day 4 (five animals), day 11 (five animals) or during anestrus (five animals). The highest concentration of manganese was present in the liver, pancreas and kidney cortex, tissues which are rich in mitochondria. Among the tissues of the reproductive tract, the corpus luteum showed the highest manganese concentration and the level increased significantly (P less than 0.01) between days 4 and 11 suggesting that this trace element may be closely related to the metabolic and possible functional characteristics of this endocrine gland. Uterine horn and caruncles contained greater manganese concentrations than other components of the reproductive tract. The significance of these findings in relation to the effect of manganese intake on ewe fertility remains to be assessed.
Record 111 of 117 in MEDLINE(R)+ (1975-1980)
TI: Bull sperm adenylate cyclase: localization and partial characterization.
AU: Herman,-C-A; Zahler,-W-L; Doak,-G-A; Campbell,-B-J
SO: Arch-Biochem-Biophys. 1976 Dec; 177(2): 622-9
Record 112 of 117 in MEDLINE(R)+ (1975-1980)
TI: Permeability of the syrian hamster placenta to manganous ions during early embryogenesis.
AU: Hanlon,-D-P; Gale,-T-F; Ferm,-V-H
SO: J-Reprod-Fertil. 1975 Jul; 44(1): 109-12
Record 113 of 117 in MEDLINE(R)+ (1975-1980)
TI: Effects on ribosomes of the substitution of spermidine or divalent cations for magnesium ions.
AU: Igarashi,-K; Sugawara,-K; Hirose,-S
SO: J-Biochem-(Tokyo). 1975 Apr; 77(4): 753-9
AB: The inactivation of rat liver ribosomes (polysomes) resulting from the replacement of bound magnesium by spermidine has been studied using a dialysis method. Inactivation of the ribosomes (polysomes) occurred when more than 40% of the Mg2+ originally bound to ribosomes in the presence of 2 mM Mg2+ was replaced by spermidine. The polypeptide-synthesizing activity of polysomes was retained partially when Mg2+ was replaced by Mn2+ by dialysis. E. coli 30S ribosomal subunits were more resistant to inactivation due to the replacement of Mg2+ by spermidine than the 50S subunits.
Record 114 of 117 in MEDLINE(R)+ (1975-1980)
TI: Development of a Mn-2+-sensitive, "soluble" adenylate cyclase in rat testis.
AU: Braun,-T; Dods,-R-F
SO: Proc-Natl-Acad-Sci-U-S-A. 1975 Mar; 72(3): 1097-101
AB: A distinctive Mn-2+-sensitive adenylate cyclase [ATP pyrophosphate-lyase(cyclizing), EC 184.108.40.206] system insensitive to fluoride has been found in rat seminiferous tubules and epididymal sperm. The development of this distinctive adenylate cyclase in testis was studied during spermatogenesis. It was first detectable in seminiferous tubules in immature rats at about the time of the first reductive divisions and the appearance of spermatid cells. The specific activity of the enzyme increased substantially during the period of spermatogenesis when spermatids develop into mature spermatozoa, and reached maximal values in the testis of adult rats. After centrifugation of testis tissue homogenates at 105,000 X g for 60 min, the Mn-2+-sensitive adenylate cyclase activity was found in the cytosol. The enzyme remains in solution after centrifugation at 300,000 X g for 5 hr or at 180,000 X g for 24 hr and passes through a 0.22 mum Millipore filter. Electron microscopic examination showed no visible membrane fragments or vesicles in the filtered supernatant. The Mn-2+-sensitive adenylate cyclase system is also present in epidiymal sperm. However, in the sperm obtained from either the caput or the cauda of epididymis, the adenylate cyclase is membrane-associated and found in particulate fractions of sperm homogenates. It therefore appears that the Mn-2+-sensitive adenylate cyclase is initially present in the cytoplasm either unattached or loosely bound to intracellular membranes and becomes firmly attached to sperm membranes later in development. This occurs either during the process of maturation of spermatids into sperm or during the transport of the testicular sperm into the epididymis.
Record 115 of 117 in MEDLINE(R)+ (1975-1980)
TI: The effect of divalent cations on bovine spermatozoal adenylate cyclase activity.
SO: J-Cyclic-Nucleotide-Res. 1975; 1(6): 271-81
AB: The effect of divalent cations on bovine sperm adenylate cyclase activity was studied. Mn2+, Co2+, Cd2+, Zn2+, Mg2+ and Ca2+ were found to satisfy the divalent cation requirement for catalysis of the bovine sperm adenylate cyclase. These divalent cations in excess of the amount necessary for the formation of the metal-ATP substrate complex were found to stimulate the enzyme activity to various degrees. The magnitude of stimulation at saturating concentrations of the divalent cations was strikingly greater with M2+ than with either Ca2+, Mg2+, Zn2+, Cd2+ or Co2+. The apparent Km was lowest for Zm2+ (0.1 - 0.2 mM) than for any of the other divalent cations tested (1.2 - 2.3 mM). The enzyme stimulation by Mn2+ was decreased by the simultaneous addition of Co2+, Cd2+, Ni2+ and particularly Zn2+ and Cu2+. The antagonism between Mn2+ and Cu2+ or Zn2+ appeared to have both competitive and non-competitive features. The inhibitory effect of Cu2+ on Mn2+-stimulated adenylate cyclase activity was prevented by 2,3-dimercaptopropanol, but not by dithiothreitol, L-ergothioneine, EDTA, EGTA or D-penicillamine. Ca2+ at concentrations of 1-5 mM was found to act synergistically with Mg2+, Zn2+, Co2+ and Mn2+ in stimulating sperm adenylate cyclase activity. The Ca2+ augmentation of the stimulatory effect of Zn2+, Co2+, Mg2+ and Mn2+ appeared to be specific.
Record 116 of 117 in MEDLINE(R)+ (1975-1980)
TI: 54Mn uptake by the ovaries and reproductive tract of cycling and anestrous ewes.
SO: Can-J-Physiol-Pharmacol. 1975 Oct; 53(5): 969-72
AB: The uptake of 54Mn by the ovaries and reproductive tract of cycling and anestrous ewes has been investigated following intravenous injection of a single dose of 54MnCl2 and sacrifice of the ewes 6 h later. The uptake of 54Mn was greater in the Graafian follicle and the corpus luteum (CL) of the cycle than in the other components of the ovary. An increased uptake of radioactivity was recorded in the CL of the 11th day of the cycle when compared with that of the 4th day. The uptake of 54Mn was lower in the corpus albicans and follicles. A low uptake of radiomanganese was found also in the various tissues of the reproductive tract. These findings indicate that manganese may play a role in the normal functioning of ovarian activity in the ewe.
Record 117 of 117 in MEDLINE(R)+ (1966-1974)
TI: Adenyl cyclase activity and cyclic 3',5'-AMP content of ejaculated monkey spermatozoa.
AU: Casillas,-E-R; Hoskins,-D-D
SO: Arch-Biochem-Biophys. 1971 Nov; 147(1): 148-55