Agonistic-antagonistic actions of clomiphene citrate on PGF2 alpha fluctuations in ovariectomized rat uterus

Effects of clomiphene and/or estrogen on uterine prostaglandin (PG) F2 alpha fluctuations in ovariectomized rats were examined. Uterine PGF2 alpha fluctuations were measured at the indicated times after injection of clomiphene and/or estradiol. Antiestrogenic effects of clomiphene on urine weight and PGF2 alpha levels were observed at 6 hr, and its effect on uterine 13,14-dihydro-15-keto-PGF2 alpha forming capacity was observed at 24 hr. At 48 and 72 hr, additive effects were recognized in all parameters. These results indicate that clomiphene possesses agonistic-antagonistic actions on the PGF2 alpha fluctuations in the uterus.