Effects of Follicle Stimulating Hormone and Luteinizing Hormone upon Cyclic AMP and Cyclic GMP Levels in Rat Ovaries<i>in Vitro</i>¹²

Abstract

In vitro effects of FSH and LH on adenosine 3′,5′-cyclic monophosphate (cyclic AMP) and guanosine 3′,5′-cyclic monophosphate (cyclic GMP) levels in rat ovarian tissue were studied. Ovaries from immature rats treated with either pregnant mare's serum (PMS) or PMS and human chorionic gonadotropin (hCG) were incubated at 37 C for 30 min in defined medium 199 containing aminophylline (0.1 mg/ml). Increasing concentrations of LH (0.4–10.0 μg) when added to the medium containing ovaries with predominantly follicular tissue (PMS-treated) produced progressive increases in cyclic AMP (29–300%) and concomitant decreases in cyclic GMP (41–70%). FSH (4–100 μg) added to the medium produced comparable changes in nucleotide levels: cyclic AMP increased 52–390% and cyclic GMP decreased 45–80%. Ovaries with predominantly luteal tissue (PMSand hCG-treated) responded differently to the same experimental conditions. LH produced a much greater increase in tissue cyclic AMP levels (209–1280%), whereas FSH produced comparable increases in cyclic AMP as seen with follicular tissue (103–570%). Neither gonadotropin caused any changes in cyclic GMP levels in luteinized ovaries. These results indicate that rat ovarian cyclic GMP is regulated by gonadotropins and the differences in the direction of nucleotide response to gonadotropins suggest divergent roles for cyclic AMP and cyclic GMP in ovarian function.