Uterine Effects from Single Treatments of Stilboestrol and Ethinyl-Estradiol in Monkeys. ∗

Abstract

Summary

Adult ovariectomized Macacus rhesus monkeys were treated with stilboestrol and ethinyl-estradiol.

A. After single oral or intramuscular doses of stilboestrol, varying from 1 mg to 200 mg, uterine bleeding occurred in from 11 to 28 days.

B. Oral treatments of stilboestrol appear to exert as prolonged an estrogenic action, as judged by time elapsing before uterine bleeding, as intramuscular injections.

C. Small doses (5-10 mg) of stilboestrol appear to be as effective as large doses (100-200 mg).

D. After oral treatments of 1/2 mg of ethinyl-estradiol uterine bleeding occurred on days 18-20.

E. No toxic or other untoward effects could be observed, even in heavy doses.