Steroid production by isolated theca and granulosa cells after initiation of atresia in the hamster.
Hypophysectomized PMSG-primed hamsters were injected with PMSG antiserum and the theca and granulosa cells of the resulting atretic follicles were incubated in vitro. In the absence of added hormone, 17 alpha-hydroxyprogesterone and oestradiol production was not detectable in granulosa cells collected and incubated at 0, 12 and 24 h after antiserum. Progesterone production was not detected in control incubations at 0 h but was measurable with cells collected at 12 h after PMSG antiserum. When incubated with androstenedione or pregnenolone (10 ng/ml for each) 17 alpha-hydroxyprogesterone and progesterone production by granulosa cells were significantly increased at 0, 12 and 24 h after antiserum. Granulosa cells were capable of aromatizing androstenedione to oestradiol at all times examined. At 0 and 12 h after antiserum to PMSG, isolated thecal shells produced androstenedione. LH stimulation caused increased androstenedione production in all thecae at 0 h, in 50% of the thecae at 12 h and in none at 24 h after antiserum. Thecal shells produced 17 alpha-hydroxyprogesterone in response to LH at 0, 12 and 24 h after antiserum, and produced progesterone at all times examined. Thecae also responded to LH with increased progesterone production up to 72 h after antiserum. These experiments demonstrate that one important steroidogenic event in atresia may be the loss of activity of C 17,20 lyase in the theca leading to loss of substrate (androstenedione) for granulosa cell aromatization, although aromatase activity is present until at least 24 h after the induction of atresia.
D019326:17-alpha-Hydroxyprogesterone; D000735:Androstenedione / Q000494:pharmacology; D000818:Animals; D006224:Cricetinae; D004958:Estradiol / Q000096:biosynthesis*; D005260:Female; D006064:Gonadotropins, Equine / Q000276:immunology; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D006908:Hydroxyprogesterones / Q000096:biosynthesis*; D007016:Hypophysectomy; D007106:Immune Sera / Q000494:pharmacology; D008647:Mesocricetus; D011284:Pregnenolone / Q000494:pharmacology; D011374:Progesterone / Q000096:biosynthesis*; D013799:Theca Cells / Q000187:drug effects / Q000378:metabolism*
D006064:Gonadotropins, Equine; D006908:Hydroxyprogesterones; D007106:Immune Sera; D000735:Androstenedione; D011374:Progesterone; D004958:Estradiol; D019326:17-alpha-Hydroxyprogesterone; D011284:Pregnenolone