Effect of glucocorticoids on spontaneous and follicle-stimulating hormone induced oocyte maturation in mouse oocytes during culture.
Several studies have indicated that glucocorticoids are involved in maturation of mammalian oocytes. Recently, maturation of porcine oocytes in culture was shown to be inhibited by glucocorticoids in a time- and dose-dependent manner. In addition, levels of cortisol available for biological action in fluid of preovulatory follicles are higher than that present in circulation. The present study evaluates the effect of cortisol and dexamethasone on mouse cumulus enclosed oocytes (CEO) undergoing spontaneous- and FSH-induced maturation during a 24h culture period using breakdown of the germinal vesicle (GVBD) as end-point. FSH-induced oocyte maturation was studied using media containing 4.5mM hypoxanthine to maintain levels of cAMP elevated, whereas spontaneous oocyte maturation was studied in a medium without hypoxanthine. In the presence of FSH (25 IU/l) the rate of GVBD was significantly elevated compared to the control. Dexamethasone (1-20 microg/ml) in combination with FSH resulted in a rate of GVBD similar to FSH alone. Cortisol (0.1-10 microg/ml) resulted in a significant higher rate of GVBD in combination with a physiological concentration of FSH (10 IU/l) as compared to the control but similar to that caused by FSH alone. Nearly all CEO that matured spontaneously resumed meiosis irrespective of whether or not cortisol was present. In conclusion, these results indicate that glucocorticoids have little or no influence on the regulation of oocyte maturation in the mouse. Species differences between mouse and pig oocytes may exist.
Andersen
Claus Yding
CY
Laboratory of Reproductive Biology, Juliane Marie Center for Children, Women and Reproduction, Section 5712, Rigshospitalet, University Hospital of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. yding@rh.dk
D000818:Animals; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006854:Hydrocortisone / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010062:Ovulation Induction
D005938:Glucocorticoids; D003907:Dexamethasone; D005640:Follicle Stimulating Hormone; D006854:Hydrocortisone