Steroidogenesis by cultured granulosa cells aspirated from human follicles using pregnenolone and androgens as precursors.
Human granulosa cells from Graafian follicles aspirated 3-4 h before the expected time of ovulation were incubated with various steroid substrates, including pregnenolone, androstenedione, testosterone and dehydroepiandrosterone (DHA). Steroid production after 3 and 10 h of incubation was determined by radioimmunoassay. Progesterone and 17alpha-hydroxyprogesterone were the major products of granulosa cells in control short-term cultures with endogenous substrates. The addition of pregnenolone increased the synthesis of progesterone and 17alpha-hydroxyprogesterone compared with the controls, although the response varied considerably between paired short-term cultures. Little or no oestradiol-17beta was produced from endogenous precursors or short-term cultures to which pregnenolone had been added; one follicle, however, produced similar amounts of oestradiol-17beta in the control cultures and after incubation with pregnenolone. When granulosa cells were cultured with various amounts of androstenedione, DHA or testosterone, large amounts of oestradiol-17beta were produced, especially in short-term cultures in which larger amounts of substrate were added. Progesterone production continued and progesterone was synthesized more rapidly or in greater amounts in some short-term test cultures than in the controls. The results indicate that human granulosa cells are one source of oestradiol-17beta during the preovulatory phase. The data support the two-cell theory for oestradiol synthesis, for granulosa cells do not appear to undertake steroid conversion via the 5-unsaturated pathway, but aromatize androgens known to be produced by thecal cells. It is also suggested that either androgens or oestradiol-17beta stimulate progesterone production by granulosa cells, at least in vitro.
D000728:Androgens / Q000378:metabolism; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D004958:Estradiol / Q000096:biosynthesis*; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D006908:Hydroxyprogesterones / Q000096:biosynthesis*; D008596:Menotropins / Q000494:pharmacology; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*
D000728:Androgens; D006063:Chorionic Gonadotropin; D006908:Hydroxyprogesterones; D011374:Progesterone; D004958:Estradiol; D008596:Menotropins; D011284:Pregnenolone