Stimulatory Effects of LH, FSH and Prostaglandins upon Cyclic 3′,5′-AMP Levels in Porcine Granulosa Cells1

Abstract

Incubation of porcine granulosa cells with 2 μg/ml FSH or LH resulted in a three- to five-fold augmentation of cyclic 3′,5′-AMP content. When gonadotropins were added in the presence of 3 HIM aminophylline a ten-fold stimulation of cyclic 3′,5′-AMP was found. The stimulatory effect of LH was greater than that of FSH. The effect of maximal doses of LH and FSH were not additive, whereas, the effects of submaximal doses were additive. LH stimulated cyclic 3′,5′-AMP within 5 min and the levels remained elevated for 3 hr. No increase in progestin secretion was found until after 3 hr. After this time the content of cyclic 3′,5′-AMP in cells dropped and secretion of progestin increased further. The addition of prostaglandin E1 and E2 stimulated the formation of cyclic 3′,5′-AMP in granulosa cells. The stimulatory effect of prostaglandin together with gonadotropins was more than additive and was not inhibited in the presence of 7-oxa-13-prostynoic acid or inhibitors of protein synthesis. These results strongly suggest that gonadotropic induction of luteinization is mediated by cyclic 3′,5′-AMP and that prostaglandins may not be mediators of gonadotropic action upon cyclic 3′,5′-AMP formation in porcine granulosa cells. (Endocrinology90: 1543, 1972)