EFFECT OF ESTRADIOL AND ESTRIOL TREATMENT ON VAGINAL ESTROGEN-RECEPTORS IN THE OVARIECTOMIZED RABBIT

Wet weight of the vagina increased > 2-fold following treatment of the ovariectomized rabbits daily for 7 days with 100 .mu.g/kg estradiol-17.beta. or estriol. The concentration of estrogen receptors expressed on the basis of mg of protein in both the cytosolic and nuclear fractions decreased significantly after treatment with estradiol or estriol. Estriol given in low doses over a long period of time apparently has as good an effect as estradiol on the vagina, and its use might be safer with respect to the effect on endometrial proliferation. [The carcinogenic implications are considered].