Effect of CDRI-85/287, a potent antiimplantation agent on uterine endometrial dimensions and peroxidase levels in rat.

CDRI compound 85/287 a potent estrogen antagonist and antiimplantation agent in rat was studied to elucidate its mechanism of action. In ovariectomized rats 85/287 treatment antagonized estrogen stimulated uterine volume density, eosinophil leucocyte infiltration, stromal mitotic cell number and peroxidase activity. In parallel experiments in pregnant rats, uterine peroxidase activity also decreased significantly as compared to controls on day 5 post-coitum. The results show that 85/287 exerts its antiimplantation activity by inhibition of responses to estradiol action.