Expression of pituitary adenylate cyclase-activating polypeptide and its type I receptor mRNA in the rat ovary

Pituitary adenylate cyclase-activating polypeptide (PACAP) exerts its action by binding to the type I PACAP preferring receptor (PACAPR) and type II receptor. In the present study, hormonal regulation of PACAP and PACAPR gene expression were examined in hormone-treated immature rat ovaries. Northern blot analysis revealed the presence of PACAPR transcript in ovaries of 21-day-old rats. However treatment with diethystilboestrol, an estrogen analogue, did not alter the levels of PACAPR. Treatment with FSH induced the transient induction of PACAP mRNA in cultured early antral follicles, reaching a maximum at 3-6 hr. We further tested progesterone production by FSH responsive cells. Treatment with PACAP-38 caused a dose-dependent increase in progesterone production The present study demonstrates the presence of PACAP and PACAPR in immature rat ovaries and stimulation of progesterone by PACAP, suggesting that PACAP may play a role in follicle growth.