Jj. Ford et Hj. Howard, ACTIVIN INHIBITION OF ESTRADIOL AND PROGESTERONE PRODUCTION IN PORCINE GRANULOSA-CELLS, Journal of animal science, 75(3), 1997, pp. 761-766
Two studies evaluated the influence of activin on steroidogenesis in c
ultured porcine granulosa cells obtained at various stages of differen
tiation. In granulosa cells isolated from 1- to 3-mm follicles, obtain
ed at random stages of the estrous cycle, treatment with activin or tr
ansforming growth factor beta (TGF beta) decreased progesterone produc
tion during the first 48 h of culture, but neither had an effect on es
tradiol production. One-half of these cells received FSH treatment at
48 h, and at 96 and 144 h of culture FSH increased estradiol and proge
sterone production. Activin or TGF beta reduced, in a dose-dependent m
anner, both basal and FSH-stimulated production of both steroids. In t
he second study, granulosa cells were obtained during follicular growt
h associated with weaning and were separated into two subpopulations (
weakly associated [WA] and tightly bound [TB]). Estradiol production i
n culture increased with time after weaning. Tightly bound cells produ
ced more estradiol than WA cells and maintained FSH-stimulated estradi
ol production, whereas production of progesterone increased in both ce
ll types after treatment with FSH. Activin depressed FSH-stimulated es
tradiol production in TB cells and depressed FSH-stimulated progestero
ne production in both cell types. These results clearly indicate that
activin depresses in vitro steroidogenesis by granulosa. cells from an
tral, porcine follicles; thus, activin may participate in atresia of a
ntral follicles of this species.