In vitro effect of prostaglandins on the accumulation of cyclic AMP in the avian oviduct.

The effects of prostaglandins E1, E2, and F2 alpha (PGE1, PGE2, and PGF2 alpha, respectively) on cyclic AMP production in tissue samples from the uterus (U), uterovaginal sphincter (UVS), and vagina (V) of regularly laying hens as well as the effects of PGE2 and forskolin on U and V of Japanese quail were studied. Both PGE1 and PGE2 enhanced cyclic AMP production in the hen oviductal segments, particularly in the V in a dose-related manner, PGE1 being the more effective agonist. PGF2 alpha had no significant effect. Quail U appeared to be less responsive to PGE2 which caused a 40% increase in cyclic AMP levels at the highest concentration tested (28 microM), whereas forskolin at 10 microM increased cyclic AMP production in quail U and V 7- and 20-fold, respectively. It is suggested that the primary function of PGE2 and PGE1 is to relax the terminal portion of the oviduct, allowing the expulsion of the egg under the contractile influence of PGF2 alpha and other oxytocic factors.