Estrogen and antagonist-induced structural changes in the cervico-vaginal epithelium of immature rats

Estrogen enhances proliferation and keratin formation in the cervico-vaginal epithelium of immature rats, whereas the estrogen antagonist, CI-628 (Parke-Davis), represses mitosis and induces mucinogenesis. Combinations of antagonist and estrogen allow differentiation of an epithelium composed of both keratin-forming and mucous cells. Both estrogen and antagonist induce synthesis of a cervico-vaginal endogenous peroxidase in the intermediate and superficial layers of the epithelium. The secreted vaginal mucus of antagonist-treated animals stains intensely for exogenous peroxidase.