摘要:

AbstractThe 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.

ISSN:0148-7280    

DOI:10.1002/mrd.1120060202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractCulture in vitro causes a slow, progressive hardening of the zona pellucida (ZP) of fully grown dictyate oocytes isolated from the mouse ovary. Hardening cannot be prevented by inhibitors of peroxidase or by a tyrosine analogue. Culture in anaerobic conditions is very effective in preventing ZP hardening. If the oocyte is cultured surrounded by its own follicle cells or in contact with cumuli oophori obtained from superovulated females, hardening is much reduced. The results suggest that the “spontaneous” hardening in cultured ovarian oocytes is not due to a cortical reaction, and that a diffusible factor is produced by follicle cells that protect the ZP from harden

ISSN:0148-7280    

DOI:10.1002/mrd.1120060203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe 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 phas

ISSN:0148-7280    

DOI:10.1002/mrd.1120060204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe 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 compactio

ISSN:0148-7280    

DOI:10.1002/mrd.1120060205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractGerm cells in the developing rabbit testis were studied using a modified squash technique. Preleptotene figures present in the postnatal testis were examined and compared with corresponding stages in ovarian germ cells. The findings indicated differences in the pattern of preleptotene changes in the developing ovary and testis.

ISSN:0148-7280    

DOI:10.1002/mrd.1120060206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe fluxes of22Na+and86Rb+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 of22Na+and86Rb+in Arbacia sperm occur predominantly by passive transport. The22Na+uptake by Arbacia oocytes showed a steady increase after an initial rapid uptake. A slight but significant inhibition of22Na+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 transpor

ISSN:0148-7280    

DOI:10.1002/mrd.1120060207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractCumulus cells are metabolically coupled to oocytes via heterologous gap junctions. This coupling terminates near the time of ovulation, and the termination appears to be correlated with the mucification of the cumulus cells lying immediately adjacent to the oocytes. The first objective of this project was to determine whether follicle stimulating hormone (FSH) induction of cumulus cell‐oocyte uncoupling could occur independently of FSH‐stimulated cumulus mucification (expansion). Intercellular coupling was measured as a percentage of radiolabeled choline (or its metabolites) that was incorporated into the oocyte relative to the total amount of radiolabel incorporated into the entire cumulus cell‐oocyte complex. It was found that the complete suppression of FSH‐stimulated cumulus expansion with chondroitin sulfate B had no suppressive effect on FSH‐stimulated cumulus cell‐oocyte uncoupling. This finding showed that FSH‐stimulated cumulus expansion was not required for cumulus cell‐oocyte uncoupling. Since 17β‐estradiol, testosterone, or progesterone could not induce maximal cumulus cell uncoupling, it was concluded that the uncoupling‐promoting action of FSH was probably not mediated by steroid hormones.A partial uncoupling of cumulus cells and oocytes was found when spontaneous oocyte maturation had occurred in the absence of FSH. This partial uncoupling was prevented by incubation of cumulus cell‐oocyte complexes in concentrations of dibutyryl cyclic adenosine monophosphate (dbcAMP) or 3‐isobutyl‐1‐methyl xanthine (IBMX) (0.25 and 0.10 mM respectively) that suppressed spontaneous oocyte maturation without inducing cumulus expansion. These inhibitors also prevented the maximal induction of uncoupling that would have been provoked by biological grade preparations of either FSH or luteinizing hormone (LH). It was concluded that two factors were required to bring about maximal cumulus cell‐oocyte uncoupling: one factor was dependent upon the action of gonadotropins on cumulus cell function, the other factor appeared to be a function of the oocytes, since maximal uncoupling could occur only after the ger

ISSN:0148-7280    

DOI:10.1002/mrd.1120060208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe effects of aphidicolin and α‐amanitin on DNA synthesis by preimplantation mouse embryos were studied. It was found that both blastocyst and 8‐cell embryos showed marked inhibition of3H‐thymidine incorporation into DNA by aphidicolin at concentrations of 20–50 μg/ml. However, aphidicolin did not inhibit the conversion of morula embryos to blastocyst embryos, although aphidicolin‐treated blastocysts lost their blastocoel and collapsed into a compact form after prolonged exposure to the drug. Both 8‐cell and blastocyst embryos were found to be susceptible to inhibition of DNA synthesis

ISSN:0148-7280    

DOI:10.1002/mrd.1120060209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractAn enriched suspension of rat epididymal epithelial cells was prepared by sequential enzymatic removal of connective tissue and peritubular cells from the epididymal tubule. The viability, structural characteristics, and pattern of polypeptides synthesized by the isolated cells were determined. Electron microscopic analysis revealed that the isolated principal cells were intact and retained their polarized morphology. Several light microscopic protocols were employed to evaluate the percentage of epithelial cells in the suspensions. These included (1) the visualization of the pattern of FITC‐lectin binding in which the principal cells could be identified by their polarized fluorescence; (2) the visualization of prominent autofluorescent granules in the cell cytoplasm which appeared to be characteristic of only epithelial cells; and (3) immunochemical staining with an antikeratin antibody which was reactive only with cells of epithelial origin. These structural probes indicated that between 80% and 90% of the isolated cells were epithelial in nature. Two‐dimensional gel electrophoresis revealed a complex pattern of polypeptides synthesized by the epithelial cells; these results are compared to those of earlier studies utilizing minced whole epididy

ISSN:0148-7280    

DOI:10.1002/mrd.1120060210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractA 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 × 108viable 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

ISSN:0148-7280    

DOI:10.1002/mrd.1120060211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY