STUDIES ON STEROIDAL ENOL ETHERS: AN ATTEMPT TO DISSOCIATE PROGESTATIONAL FROM CONTRACEPTIVE ACTIVITY IN ORAL GESTAGENS

Abstract

As a further step in a program of biological investigations of enol ethers of δ⁴-3-ketosteroid compounds, 17α-acetoxyprogesterone cyclopentyl enol ether was tested orally on rabbits for progestational effects and on rats for other endocrine activities. The compound proved very effective in the Clauberg assay and in maintaining pregnancy in spayed rabbits, but it was practically inactive in the intrauterine assay. On the other hand it failed to interfere with estrus, mating, ovulation, pregnancy and delivery at term in the rat. In addition, neither impairment of gonadotropic pituitary function, nor masculinizing action on the external genitalia of fetuses was observed. The bearing of these findings on the possibility of having developed a pure progestational substance is discussed.