[Maturation of the follicle-enclosed common frog oocytes stimulated by low progesterone concentrations depends on transcription].
The maturation of follicle-enclosed common frog oocytes stimulated by low progesterone concentration is inhibited by actinomycin D (5 micrograms/ml). The concentrations of progesterone, at which oocyte maturation was inhibited by actinomycin D, varied with the season and were different in different females. The inhibitor of steroidogenesis aminogluthetimide (100 micrograms/ml) did not suppress the maturation of follicle-enclosed oocytes in most experiments, which was induced by both high and low progesterone concentrations. The induction of maturation of the defolliculated ("denuded") oocytes required lower progesterone concentrations than of the follicle-enclosed oocytes and, in addition, the maturation of denuded oocytes was not suppressed by actinomycin D. Thus, it was shown for the first time that low doses of progesterone induced the maturation of amphibian oocytes while acting on the follicle wall cells and this process depended on transcription. The factor inducing or enhancing maturation, which is formed in the follicle cells in the presence of low progesterone concentrations, remains as yet unknown.
Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, ul. Vavilova 26, Moscow, 119991 Russia. skoblina@proxima.idb.ac.ru
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D000616:Aminoglutethimide / Q000494:pharmacology; D000818:Animals; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D009866:Oogenesis / Q000187:drug effects / Q000502:physiology; D006080:Ovarian Follicle / Q000187:drug effects / Q000502:physiology*; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D011896:Rana temporaria / Q000502:physiology*; D012621:Seasons; D014158:Transcription, Genetic
D000616:Aminoglutethimide; D003609:Dactinomycin; D011374:Progesterone