Stimulatory Action of Gonadotropins and Prostaglandins on Adenosine-3′,5′-Monophosphate Production by Isolated Rat Granulosa Cells1

Abstract

The effect of purified preparations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), and of prostaglandins [PG], on cyclic[c]AMP production by granulosa cells isolated from ovaries of intact immature estrogen-treated rats was studied. Incubation of the cells with FSH resulted in a 60-fold increase in cAMP production in 10 min. Both NIH[National Institute of Health]-LH and purified LH (LH-HP) were able to elicit only slight increases in cAMP production. PGE1 and E2, but not PGF2.alpha., were also able to stimulate cAMP production, although not to as great an extent as FSH. The stimulatory action of FSH was not antagonized in the presence of inhibitors of PG synthesis, suggesting that PG biosynthesis does not mediate the action of FSH on cAMP production. The ability of both FSH and LH to stimulate cAMP production in granulosa cells from estrogen-treated rats was slightly decreased when compared to granulosa cells from non-treated rats. The ability of both FSH and LH to stimulate cAMP production was significantly increased in granulosa cells from pregnant mare''s serum gonadotropin (PMS)-treated rats compared to those from estrogen-treated rats. The difference in the response to LH was the most marked, LH being as effective as FSH in stimulating cAMP production in granulosa cells from PMS-treated rats. These results demonstrate a preferential stimulatory action of FSH on granulosa cells from either non-treated or estrogen-treated immature rats, indicating a predominance of adenylate cyclase-coupled FSH receptors in these cells. Induction of follicular maturation with PMS appeared to increase the number of adenylate cyclase-coupled LH receptors.