Effect of pituitary adenylate cyclase-activating polypeptide (PACAP) on production of progesterone in cultured luteal cells from rat ovary

摘要

The aim of this study was to examine the effects of pituitary adenylate cyclase-activating polypeptide (PACAP) on production of progesterone in cultured luteal cells from immature rats treated with pregnant mare serum gonadotropin and human chorionic gonadotropin. Luteal cells were cultured for 24 h with and without ovine luteinizing hormone (LH; 100 ng/ml) and/or PACAP-38 (10, 100 and 1,000 ng/ml). After incubation, the incubation media were collected and progesterone, 20 alpha-hydroxy-4-pregnene-3-one (20 alpha-OH-P), and cyclic adenosine 3',5'-monophosphate (cAMP) levels were measured. PACAP-38 alone significantly stimulated the production of progesterone and accumulation of cAMP in a dose-dependent manner (P < 0.05 and 0.001, respectively, ANOVA). LH-induced production of progesterone and cAMP were significantly decreased by increasing concentrations of PACAP (P < 0.05 and 0.05, respectively, ANOVA). Since PACAP significantly decreased the ratio of progesterone to 20 alpha-OH-P production in LH-stimulated cells in a dose-dependent manner (P < 0.001, ANOVA), inhibitory action of PACAP on the LH-induced increase in progesterone production may be involved in the initiation of luteolysis. The results suggest that PACAP plays an important role as a regulatory hormone in luteal cell function and the reproductive process.