Experiments were designed to test the effects of simple sugars and complex polysaccharides on the attachment of mammalian spermatozoa with the zona pellucida. In the guinea pig, L-fucose was a twofold better inhibitor of the attachment compared to other sugars at 50 mM. Fucoidin, an algal polysaccharide rich in sulfated L-fucose, was a very potent inhibitor, completely blocking attachment at a concentration of 100 μg/ml. Several other highly sulfated glycosaminoglycans showed no inhibitory activity, suggesting the fucoidin effect was not simply due to its charge or sulfate. In addition, fragments of fucoidin, generated by partial hydrolysis and isolated using Biogel P-2, were nearly as inhibitory as the native molecule on a weight basis. Fucoidin also inhibited sperm-zona attachment in the hamster and human; thus, its effect is not species specific. The data suggest that L-fucose may be part of a recognition signal between mammalian gametes.
{"title":"Evidence suggesting that L‐fucose is part of a recognition signal for sperm‐zona pellucida attachment in mammals","authors":"Thomas T. F. Huang, E. Ohzu, R. Yanagimachi","doi":"10.1002/MRD.1120050406","DOIUrl":"https://doi.org/10.1002/MRD.1120050406","url":null,"abstract":"Experiments were designed to test the effects of simple sugars and complex polysaccharides on the attachment of mammalian spermatozoa with the zona pellucida. In the guinea pig, L-fucose was a twofold better inhibitor of the attachment compared to other sugars at 50 mM. Fucoidin, an algal polysaccharide rich in sulfated L-fucose, was a very potent inhibitor, completely blocking attachment at a concentration of 100 μg/ml. Several other highly sulfated glycosaminoglycans showed no inhibitory activity, suggesting the fucoidin effect was not simply due to its charge or sulfate. In addition, fragments of fucoidin, generated by partial hydrolysis and isolated using Biogel P-2, were nearly as inhibitory as the native molecule on a weight basis. Fucoidin also inhibited sperm-zona attachment in the hamster and human; thus, its effect is not species specific. The data suggest that L-fucose may be part of a recognition signal between mammalian gametes.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"8 1","pages":"355-361"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79322796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Fournier-delpech, J. Courtens, C. Pisselet, B. Delaleu, M. Courot
To assess the ability of ram spermatozoa to bind to oocytes, spermatozoa (2.5–200 × 106/500μ1) taken from the rete testis, or from various regions of the epididymis (head, body, and tail) were mixed with cumulus-free heterologous oocytes obtained from immature superovulated rats. After incubation for 30–45 min in Parker 199 Hepes medium at 35°C, testicular spermatozoa were unable to bind to the zona at any of the concentrations used. However, spermatozoa from the middle body of the epididymus were able to bind to the zona and this binding reached a maximum in the distal body and in the tail of the epididymis. The spermatozoa were bound by their heads. Electron microscopy showed that the plasma membrane and the acrosome of the bound sperm remained intact, without any sign of an acrosome reaction.
{"title":"Acquisition of zona binding by ram spermatozoa during epididymal passage, as revealed by interaction with rat oocytes","authors":"S. Fournier-delpech, J. Courtens, C. Pisselet, B. Delaleu, M. Courot","doi":"10.1002/MRD.1120050410","DOIUrl":"https://doi.org/10.1002/MRD.1120050410","url":null,"abstract":"To assess the ability of ram spermatozoa to bind to oocytes, spermatozoa (2.5–200 × 106/500μ1) taken from the rete testis, or from various regions of the epididymis (head, body, and tail) were mixed with cumulus-free heterologous oocytes obtained from immature superovulated rats. After incubation for 30–45 min in Parker 199 Hepes medium at 35°C, testicular spermatozoa were unable to bind to the zona at any of the concentrations used. However, spermatozoa from the middle body of the epididymus were able to bind to the zona and this binding reached a maximum in the distal body and in the tail of the epididymis. The spermatozoa were bound by their heads. Electron microscopy showed that the plasma membrane and the acrosome of the bound sperm remained intact, without any sign of an acrosome reaction.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"04 1","pages":"403-408"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80050283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A collection procedure has been developed to improve the homogeneity of mammalian spermatid populations separated by elutriation. Trypsinizied ram testis cells were elutriated at 18C. Every cell population was eluted by progressive changes in the flow rate and/or rotor speed, instead of by abrupt changes, to reduce the contamination by cells from the next population. Pure populations were collected alternating with mixed populations corresponding to the overlap between two adjacent pure populations. Furthermore, each pure population was collected into two subfractions, the second of which, contamined by cells from the following population, was pooled with the following fraction. In less than 2 hr after castration, three populations of at least 1 × 108 viable round or elongated or elongating spermatids were obtained with respective purities of 95%, 82%, and 99% of the nucleated cells. In addition, two mixed populations containing only two adjacent spermatid types (round plus elongating spermatids: 98%; elongated plus elongating spermatids: 98%) were obtained, as well as a population containing around 60% pachytene spermatocytes.
{"title":"A strategy for an improved separation of mammalian spermatids","authors":"M. Loir, M. Lanneau","doi":"10.1002/MRD.1120060211","DOIUrl":"https://doi.org/10.1002/MRD.1120060211","url":null,"abstract":"A collection procedure has been developed to improve the homogeneity of mammalian spermatid populations separated by elutriation. Trypsinizied ram testis cells were elutriated at 18C. Every cell population was eluted by progressive changes in the flow rate and/or rotor speed, instead of by abrupt changes, to reduce the contamination by cells from the next population. Pure populations were collected alternating with mixed populations corresponding to the overlap between two adjacent pure populations. Furthermore, each pure population was collected into two subfractions, the second of which, contamined by cells from the following population, was pooled with the following fraction. In less than 2 hr after castration, three populations of at least 1 × 108 viable round or elongated or elongating spermatids were obtained with respective purities of 95%, 82%, and 99% of the nucleated cells. In addition, two mixed populations containing only two adjacent spermatid types (round plus elongating spermatids: 98%; elongated plus elongating spermatids: 98%) were obtained, as well as a population containing around 60% pachytene spermatocytes.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"27 1","pages":"179-188"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75710968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The visualization of human male pronuclear chromosomes is possible by utilizing a technique in which human sperm fertilize zona-free Golden hamster (Mesocricetus auratus) ova in vitro. R banding of these chromosomes can be achieved by adding 20 μg/ml 5-bromode-oxyuridine (BrdU), a thymidine analogue, to the culture medium during mid-to-late S phase and subsequently staining the chromosomes with 0.1 mg/ml acridine orange. BrdU was added 3.0–10.0 hr postinsemination (hr pi). R bands were obtained when fertilized eggs were transferred into medium containing BrdU between 5.0 and 6.5 hr pi. This indicates that the human (male) pronuclear chromosomes were in mid-to-late S phase at these times.
{"title":"Timing of human sperm chromosome replication following fertilization of hamster eggs in vitro","authors":"W. Balkan, Renée H. Martin","doi":"10.1002/MRD.1120060204","DOIUrl":"https://doi.org/10.1002/MRD.1120060204","url":null,"abstract":"The visualization of human male pronuclear chromosomes is possible by utilizing a technique in which human sperm fertilize zona-free Golden hamster (Mesocricetus auratus) ova in vitro. R banding of these chromosomes can be achieved by adding 20 μg/ml 5-bromode-oxyuridine (BrdU), a thymidine analogue, to the culture medium during mid-to-late S phase and subsequently staining the chromosomes with 0.1 mg/ml acridine orange. BrdU was added 3.0–10.0 hr postinsemination (hr pi). R bands were obtained when fertilized eggs were transferred into medium containing BrdU between 5.0 and 6.5 hr pi. This indicates that the human (male) pronuclear chromosomes were in mid-to-late S phase at these times.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"42 1","pages":"115-119"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90132673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The bioelectric responses at fertilization of the sea urchin Lytechinus variegatus are a complex series of membrane potential and resistance changes that occur concomitant with gamete fusion, ionic fluxes, and the cortical granule discharge. This work attempts to separate the electrical effects of sperm-egg interactions from those of the cortical reactions. Two approaches were taken to discern the electrical events associated with insemination, distinct from cortical granule discharge: (1) fertilization of eggs treated with 3% urethane, 10 mM procaine, or 10 mM nicotine, to prevent the cortical reaction and (2) refertilization of fertilized eggs (denuded with 1 mM aminotriazole containing 1 mg/ml soybean trypsin inhibitor). Cortical granule discharge in the absence of sperm incorporation was investigated by artificial activation with 5 μM A23187 or by fertilization in the presence of 10 μM cytochalasin D, which prevents incorporation. These results are consistent with a model in which the sperm-egg interaction triggers both a rapid (50-400 msec), but minor (≅10 mV), electrical transient that leads to an action potential and then both the Na+-dependent fast block to polyspermy and the late block resulting from the secretion of the cortical granules.
{"title":"Bioelectric responses at fertilization : separation of the events associated with insemination from those due to the cortical reaction in sea urchin, Lytechinus variegatus","authors":"D. Hülser, G. Schatten","doi":"10.1002/MRD.1120050407","DOIUrl":"https://doi.org/10.1002/MRD.1120050407","url":null,"abstract":"The bioelectric responses at fertilization of the sea urchin Lytechinus variegatus are a complex series of membrane potential and resistance changes that occur concomitant with gamete fusion, ionic fluxes, and the cortical granule discharge. This work attempts to separate the electrical effects of sperm-egg interactions from those of the cortical reactions. Two approaches were taken to discern the electrical events associated with insemination, distinct from cortical granule discharge: (1) fertilization of eggs treated with 3% urethane, 10 mM procaine, or 10 mM nicotine, to prevent the cortical reaction and (2) refertilization of fertilized eggs (denuded with 1 mM aminotriazole containing 1 mg/ml soybean trypsin inhibitor). Cortical granule discharge in the absence of sperm incorporation was investigated by artificial activation with 5 μM A23187 or by fertilization in the presence of 10 μM cytochalasin D, which prevents incorporation. These results are consistent with a model in which the sperm-egg interaction triggers both a rapid (50-400 msec), but minor (≅10 mV), electrical transient that leads to an action potential and then both the Na+-dependent fast block to polyspermy and the late block resulting from the secretion of the cortical granules.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"143 1","pages":"363-377"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82192558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The fluxes of 22Na+ and 86Rb+ in Arbacia sperm and oocytes were studied in order to determine how these cells carry out cation exchange with the sea environment. The uptake of these ions by serum followed a pattern of early rapid influx (initial 0.5 min) and subsequent efflux (1–3 min) followed by a gradual uptake (after 3 min). Neither the uptake nor the efflux of these cations by Arbacia sperm were affected by ouabain, suggesting that influx and efflux of 22Na+ and 86Rb+ in Arbacia sperm occur predominantly by passive transport. The 22Na+ uptake by Arbacia oocytes showed a steady increase after an initial rapid uptake. A slight but significant inhibition of 22Na+ uptake was observed with ouabain. However, 86Rb+ uptake by the oocytes reached an early equilibrium and was not affected by ouabain. The uptake of Rb+ by Arbacia oocyte is by passive transport while that of Na+ is both by passive and active transport.
{"title":"22Na+ and 86Rb+ fluxes in spermatozoa and oocytes of arbacia punctulata","authors":"O. Adeyemo, S. Koide","doi":"10.1002/MRD.1120060207","DOIUrl":"https://doi.org/10.1002/MRD.1120060207","url":null,"abstract":"The fluxes of 22Na+ and 86Rb+ in Arbacia sperm and oocytes were studied in order to determine how these cells carry out cation exchange with the sea environment. The uptake of these ions by serum followed a pattern of early rapid influx (initial 0.5 min) and subsequent efflux (1–3 min) followed by a gradual uptake (after 3 min). Neither the uptake nor the efflux of these cations by Arbacia sperm were affected by ouabain, suggesting that influx and efflux of 22Na+ and 86Rb+ in Arbacia sperm occur predominantly by passive transport. The 22Na+ uptake by Arbacia oocytes showed a steady increase after an initial rapid uptake. A slight but significant inhibition of 22Na+ uptake was observed with ouabain. However, 86Rb+ uptake by the oocytes reached an early equilibrium and was not affected by ouabain. The uptake of Rb+ by Arbacia oocyte is by passive transport while that of Na+ is both by passive and active transport.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"375 1","pages":"135-143"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80555353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study determines the effect of a specific and an irreversible inhibitor of histidine decarboxylase (HDC), α-fluoromethylhistidine (α-FMH) on the mouse preimplantation embryo development in vitro. The embryo culture technique was used to assess the effect of α-FMH. Embryos recovered at 0800–0900 hr (AM) on day 3 of pregnancy were 4–8 cells, whereas those recovered at 1600–1630 hr were mostly 8-cell compacted embryos. Of the day 3-AM embryos, 81.3 ± 4.3% developed to blastocysts within 48 hr when cultured in the medium alone, but addition of α-FMH (0.19 or 0.38 mM) drastically reduced the blastocyst formation to 26.6 ± 7 or 16.8 ± 4.3%. Most of them were arrested before the compaction stage. Addition of L-histidine, the substrate for HDC, did not alter the inhibition of blastocyst formation in the presence of α-FMH (37.2 ± 10.9%). Of the day 3-PM embryos, 99.3 ± 0.7% developed to blastocyst stage when cultured in the medium alone and addition of α-FMH (0.19 or 0.38 mM) did not affect the embryo development (92.1 ± 4.3 or 81.9 ± 9.9% developed to blastocysts). The birth of healthy young following transfer of these blastocysts into pseudopregnant mice indicates normal development of the embryos under this condition. The results suggest that histamine synthesis may be required for the process of compaction and thus the formation of blastocyst.
{"title":"Preimplantation embryo development in the mouse: Role of histidine decarboxylase","authors":"L. Hudgins, S. Mukerjee, S. Dey","doi":"10.1002/MRD.1120060205","DOIUrl":"https://doi.org/10.1002/MRD.1120060205","url":null,"abstract":"The present study determines the effect of a specific and an irreversible inhibitor of histidine decarboxylase (HDC), α-fluoromethylhistidine (α-FMH) on the mouse preimplantation embryo development in vitro. The embryo culture technique was used to assess the effect of α-FMH. Embryos recovered at 0800–0900 hr (AM) on day 3 of pregnancy were 4–8 cells, whereas those recovered at 1600–1630 hr were mostly 8-cell compacted embryos. Of the day 3-AM embryos, 81.3 ± 4.3% developed to blastocysts within 48 hr when cultured in the medium alone, but addition of α-FMH (0.19 or 0.38 mM) drastically reduced the blastocyst formation to 26.6 ± 7 or 16.8 ± 4.3%. Most of them were arrested before the compaction stage. Addition of L-histidine, the substrate for HDC, did not alter the inhibition of blastocyst formation in the presence of α-FMH (37.2 ± 10.9%). Of the day 3-PM embryos, 99.3 ± 0.7% developed to blastocyst stage when cultured in the medium alone and addition of α-FMH (0.19 or 0.38 mM) did not affect the embryo development (92.1 ± 4.3 or 81.9 ± 9.9% developed to blastocysts). The birth of healthy young following transfer of these blastocysts into pseudopregnant mice indicates normal development of the embryos under this condition. The results suggest that histamine synthesis may be required for the process of compaction and thus the formation of blastocyst.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"85 1","pages":"121-125"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90676751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent claims that bull sperm display chemotaxis to synthetic peptides known to be chemotactically active for neutrophils are not based on direct observation of sperm behavior. When these observations are made, no change in sperm motility or direction is seen. The supposed chemoattractant effect is probably based on disruption by the peptides of the sperm acrosome, resulting in increased sperm adhesion to the glass surface inside the pipette containing the supposed chemoattractive peptide.
{"title":"Synthetic peptides are not chemoattractants for bull sperm","authors":"Richard L. Miller","doi":"10.1002/MRD.1120050409","DOIUrl":"https://doi.org/10.1002/MRD.1120050409","url":null,"abstract":"Recent claims that bull sperm display chemotaxis to synthetic peptides known to be chemotactically active for neutrophils are not based on direct observation of sperm behavior. When these observations are made, no change in sperm motility or direction is seen. The supposed chemoattractant effect is probably based on disruption by the peptides of the sperm acrosome, resulting in increased sperm adhesion to the glass surface inside the pipette containing the supposed chemoattractive peptide.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"57 1","pages":"395-401"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87839700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of zinc on human sperm motility, fertilizing capacity (as assessed by penetration of human spermatozoa into the zona pellucida-free hamster oocyte), and nuclear chromatin decondensation were investigated using spermatozoa from four fertile donors. Both sperm motility and the penetration of sperm into zona-free hamster ova were consistently impaired in media containing 1,000 μM zinc. Spermatozoa from one man were similarly affected at a concentration of 500 μM zinc, but no adverse effects were noted at this zinc concentration in experiments with other donors. Since decreased fertilizing capacity in response to zinc was always accompanied by a significant decline in both the percentage of motile cells and mean swimming speeds, it appears that all of these results reflect a general toxic effect on the cells. At lower concentrations (125–250 μM), zinc had no effect on human sperm motility nor their ability to undergo capacitation and penetrate zona-free hamster ova in vitro. For some donors, zinc (125–500 μM) stimulated both the attachment of spermatozoa to the hamster vitellus and the incorporation of spermatozoa into the hamster ooplasm. The decondensation of human sperm nuclear chromatin in sodium dodecyl sulfate was largely inhibited when zinc was added to the medium, but no significant changes in nuclear stability were apparent after capacitation in zinc-free medium. We conclude that zinc, when present in subtoxic concentrations, does not adversely affect the ability of human spermatozoa to undergo capacitation and penetrate zona-free hamster ova in vitro.
{"title":"Zinc does not inhibit the capacitation of human spermatozoa in vitro","authors":"W. Blazak, J. Overstreet","doi":"10.1002/MRD.1120050205","DOIUrl":"https://doi.org/10.1002/MRD.1120050205","url":null,"abstract":"The effects of zinc on human sperm motility, fertilizing capacity (as assessed by penetration of human spermatozoa into the zona pellucida-free hamster oocyte), and nuclear chromatin decondensation were investigated using spermatozoa from four fertile donors. Both sperm motility and the penetration of sperm into zona-free hamster ova were consistently impaired in media containing 1,000 μM zinc. Spermatozoa from one man were similarly affected at a concentration of 500 μM zinc, but no adverse effects were noted at this zinc concentration in experiments with other donors. Since decreased fertilizing capacity in response to zinc was always accompanied by a significant decline in both the percentage of motile cells and mean swimming speeds, it appears that all of these results reflect a general toxic effect on the cells. At lower concentrations (125–250 μM), zinc had no effect on human sperm motility nor their ability to undergo capacitation and penetrate zona-free hamster ova in vitro. For some donors, zinc (125–500 μM) stimulated both the attachment of spermatozoa to the hamster vitellus and the incorporation of spermatozoa into the hamster ooplasm. The decondensation of human sperm nuclear chromatin in sodium dodecyl sulfate was largely inhibited when zinc was added to the medium, but no significant changes in nuclear stability were apparent after capacitation in zinc-free medium. We conclude that zinc, when present in subtoxic concentrations, does not adversely affect the ability of human spermatozoa to undergo capacitation and penetrate zona-free hamster ova in vitro.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"119 1","pages":"153-160"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88055433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The follicle wall was previously shown to be involved in insulin induction of oocyte maturation in Rana pipiens ovarian follicles. Steroidogenic involvement in insulin induction of maturation was investigated following development of a radioimmunoassay (RIA) for progesterone to measure endogenous progesterone associated with in vitro incubates. Insulin and frog pituitary homogenate (FPH) were both found to elevate progesterone levels significantly in these incubates. FPH was more effective in elevating progesterone levels than insulin and caused progesterone increase of about 2 orders of magnitude greater than insulin. Removal of the follicle wall eliminated the steroidogenic effects of insulin. Considerable interanimal variation was observed in the ability of insulin to induce oocyte germinal vesicle breakdown (GVBD) in intact follicles. The hypothesis was proposed that differences in endogenous progesterone might explain this variation. To test this hypothesis, an experiment was carried out in which hormone production and follicular sensitivity to insulin were simultaneously determined in follicles obtained from the same animals. Results of the experiment show that the ability of insulin to induce GVBD, as indicated by the effective concentration needed for 50% response (ED50), was strongly correlated with the levels of endogenous progesterone as measured by RIA. The results provide direct evidence that insulin's action on the follicle wall involves steroid production. It was thus concluded that increased endogenous progesterone facilitates GVBD induction by insulin. It is unclear how the two hormones interact to produce an enhanced effect, but interactions at the receptor or postreceptor level may be involved. This follicle system may provide important insights into the mode of action and interaction of these two important hormones.
{"title":"Insulin induction of meiosis of rana pipiens oocytes: Relation to endogenous progesterone","authors":"C. Lessman, A. Schuetz","doi":"10.1002/MRD.1120060202","DOIUrl":"https://doi.org/10.1002/MRD.1120060202","url":null,"abstract":"The follicle wall was previously shown to be involved in insulin induction of oocyte maturation in Rana pipiens ovarian follicles. Steroidogenic involvement in insulin induction of maturation was investigated following development of a radioimmunoassay (RIA) for progesterone to measure endogenous progesterone associated with in vitro incubates. Insulin and frog pituitary homogenate (FPH) were both found to elevate progesterone levels significantly in these incubates. FPH was more effective in elevating progesterone levels than insulin and caused progesterone increase of about 2 orders of magnitude greater than insulin. Removal of the follicle wall eliminated the steroidogenic effects of insulin. Considerable interanimal variation was observed in the ability of insulin to induce oocyte germinal vesicle breakdown (GVBD) in intact follicles. The hypothesis was proposed that differences in endogenous progesterone might explain this variation. To test this hypothesis, an experiment was carried out in which hormone production and follicular sensitivity to insulin were simultaneously determined in follicles obtained from the same animals. Results of the experiment show that the ability of insulin to induce GVBD, as indicated by the effective concentration needed for 50% response (ED50), was strongly correlated with the levels of endogenous progesterone as measured by RIA. The results provide direct evidence that insulin's action on the follicle wall involves steroid production. It was thus concluded that increased endogenous progesterone facilitates GVBD induction by insulin. It is unclear how the two hormones interact to produce an enhanced effect, but interactions at the receptor or postreceptor level may be involved. This follicle system may provide important insights into the mode of action and interaction of these two important hormones.","PeriodicalId":12668,"journal":{"name":"Gamete Research","volume":"34 1","pages":"95-106"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73245993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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