title: Androgen synthesis during follicular development: evidence that rat granulosa cell 17-ketosteroid reductase is independent of hormonal regulation.
abstract: Although androgens have been implicated in follicular atresia, ovarian follicular androgen synthesis is required for preovulatory follicular growth. To localize the site(s) of androgen biosynthesis and to obtain a better understanding of the regulation of the androgenic pathway(s) in rat ovarian follicles we examined the relative abilities of developing follicles to accumulate specific androgens [testosterone (T) and dihydrotestosterone (DHT)] using both radioimmunoassay (RIA) and 3H-substrate metabolism techniques. Small antral and preovulatory follicles were obtained from control or human chorionic gonadotropin (hCG)-primed immature rats, respectively (Richards and Bogovich, 1982). Small antral follicles, theca and granulosa cells produced little immunoassayable androgen (T + DHT) when incubated with or without 8-bromo-cAMP. In contrast, preovulatory follicles and theca produced more androgen than small antral tissues and in a manner acutely stimulable by cAMP. Granulosa cells produced little androgen under these conditions. Inclusion of [3H] androstenedione in the incubates yielded increased accumulation of [3H] T and [3H] DHT for all small antral and preovulatory tissues. Indeed, granulosa cells from both small antral and preovulatory follicles possessed a remarkable ability to accumulate [3H] T. This ability was not altered by hypophysectomy or subsequent treatment with estradiol and/or follicle-stimulating hormone (FSH). These results suggest that 17-ketosteroid reductase may be a constitutive enzyme in granulosa cells.
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000032:analysis*; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000032:analysis; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000728:Androgens / Q000096:biosynthesis*; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D013196:Dihydrotestosterone / Q000096:biosynthesis; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000201:enzymology*; D007016:Hypophysectomy; D066298:In Vitro Techniques; D006080:Ovarian Follicle / Q000502:physiology*; D051381:Rats; D013739:Testosterone / Q000096:biosynthesis; D013799:Theca Cells / Q000378:metabolism
chemical_list: D000728:Androgens; D013196:Dihydrotestosterone; D015124:8-Bromo Cyclic Adenosine Monophosphate; D013739:Testosterone; D000735:Androstenedione; D004958:Estradiol; D005640:Follicle Stimulating Hormone; D015067:17-Hydroxysteroid Dehydrogenases; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase