Comparison between the progestin secretion responsiveness to gonadotrophins of rat cumulus and mural granulosa cells in vitro.
Several studies have shown differences in gonadotrophin receptor content between different granulosa cell (gc) populations within the ovarian follicle, but little is known about the gonadotrophin sensitivity in gc from different parts of the follicle. This study is an investigation of progestin synthesis and responsiveness to highly purified human and partly purified rat gonadotrophins. It involves short-term culture of rat cumulus and mural gc obtained from preovulatory follicles of PMSG-treated immature rats. The responsiveness to FSH in terms of progestin accumulation was similar in the two gc populations, whereas the responsiveness to LH was greater in the mural gc than in the cumulus. The morphological response in the cumulus cells (mucification) correlated with the steroidogenic response. The pattern of progestin synthesis differed between the two gc populations. In the cumulus gc progesterone was dominant, whereas 20 alpha-dihydroprogesterone was the main progestin secreted in the mural gc. The difference in responsiveness to gonadotrophins correlates well with the reported differences in receptor content in the two gc populations.
D004092:20-alpha-Dihydroprogesterone / Q000378:metabolism; D000818:Animals; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006064:Gonadotropins, Equine / Q000494:pharmacology; D006107:Granulosa Cells / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects; D006080:Ovarian Follicle / Q000378:metabolism*; D011374:Progesterone / Q000378:metabolism; D011372:Progestins / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism; D011962:Receptors, FSH; D011974:Receptors, LH; D013997:Time Factors
D006064:Gonadotropins, Equine; D011372:Progestins; D011956:Receptors, Cell Surface; D011962:Receptors, FSH; D011974:Receptors, LH; D004092:20-alpha-Dihydroprogesterone; D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone