Participation of vasoactive intestinal polypeptide in ovarian steroids production during the rat estrous cycle and in the development of estradiol valerate-induced polycystic ovary

Abstract

Vasoactive intestinal polypeptide (VIP) stimulates estradiol and progesterone release from ovarian granulosa cells in vitro. Very little information is available as to the role VIP plays in the control of steroid secretion during reproductive cyclicity and in ovarian pathologies involving altered steroid secretion. In this study, we determined the involvement of VIP in regulating ovarian androgen and estradiol release during estrous cyclicity and estradiol valerate (EV)-induced polycystic ovarian development in rats. Our findings show that androgen and estradiol release from ovaries obtained during different stages of rat estrous cycle mimic cyclic changes in steroid release observed in vivo with maximal release occurring during late proestrus. VIP increased androgen release from ovaries of all cycle stages except late proestrus and estradiol release from all cycle stages. Increases in VIP-induced androgen and estradiol release were maximal at early proestrus. Inclusion of saturating c