Studies on Steroidal Ethers: Oral Activity of 3-Cyclopentyl Ethers of Estrogenic Steroids

Abstract

The uterotrophic activities of estrone, estradiol-17β, 17α-ethynylestradiol, 17α-methylestradiol, estriol and 17-epiestriol in immature female mice were compared with those of their 3-cyclopentyl ethers. With all the ether derivatives the effective doses were smaller, the slopes of the dose-response curves were steeper and the maximal uterus weight attainable was greater than when the parent compounds were used. Moreover, unlike estriol, its 3-cyclopentyl ether did not show inhibiting effects against the uterine growth induced by estrone administered concurrently, thus no longer behaving as an impeded estrogen.