A possible involvement of prostaglandin F2 alpha (PGF2 alpha) in Rana esculenta ovulation: effects of mammalian gonadotropin-releasing hormone on in vitro PGF2 alpha and 17 beta-estradiol production from ovary and oviduct.

The present work studied the PGF2 alpha and 17 beta-estradiol plasma levels during ovulation, and the in vitro effects of mammalian gonadotropin-releasing hormone (mGnRH) on ovarian and oviductal production of prostaglandin F2 alpha (PGF2 alpha) and 17 beta-estradiol during four different stages of the annual sexual cycle in water frog, Rana esculenta. Plasma levels of PGF2 alpha increased in ovulating frogs, with respect to preovulatory and postovulatory levels, while estradiol did not change. In addition, mGnRH increased PGF2 alpha and 17 beta-estradiol in the incubation media of ovaries taken during the recovery stage. Moreover, mGnRH increased PGF2 alpha in incubation media of oviducts collected during the reproductive stage. These findings suggest that PGF2 alpha could be involved in the control of egg deposition in the female R.