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 prostaglandins PGE and PGF 2α in the rat uterus. Uterine tissue was obtained from ovariectomized adult rats with or without estradiol-17 beta treatment. Prolactin (4 IU/ml) enhanced PGE uterine synthesis. At higher concentrations (10–15 IU/ml) prolactin enhanced PGE levels and diminished PGF 2α production by uterine tissue from ovariectomized rats. When ovariectomized rats were injected with estradiol-17 beta, we observed a pattern of PGE and PGF 2α uterine synthesis similar to that of ovariectomized rats. However, the stimulatory action of PRL on PGE synthesis was augmented in the estrogenized animals. These results led us to conclude that: 1)-PRL exerts a luteotrophic action by regulating uterine tissue PGE synthesis, 2-estradiol-17 beta potentiates this action.