PROLACTIN REGULATES UTERINE SYNTHESIS OF PROSTAGLANDINS IN OVARIECTOMIZED RATS - EFFECT OF ESTRADIOL-17-BETA

We studied the in vitro effect of prolactin on the synthesis of prosta glandins PGE and PGF(2 alpha) in the rat uterus. Uterine tissue was ob tained from ovariectomized adult rats with or without estradiol-17 bet a treatment. Prolactin (4 IU/ml) enhanced PGE uterine synthesis. At hi gher concentrations (10-15 IU/ml) prolactin enhanced PGE levels and di minished PGF(2 alpha) production by uterine tissue from ovariectomized rats. When ovariectomized rats were injected with estradiol-17 beta, we observed a pattern of PGE and PGF(2 alpha) uterine synthesis simila r to that of ovariectomized rats, However, the stimulatory action of P RL on PGE synthesis was augmented in the estrogenized animals. These r esults led us to conclude that: 1)-PRL exerts a luteotrophic action by regulating uterine tissue PGE synthesis, 2-estradiol-17 beta potentia tes this action.