Progesterone-Like Activity of a Series of 19-Nortestosterones

Abstract

The progestational activity of a series of 19-nortestosterones was studied after both systemic and intrauterine injection in estrogen primed rabbits. With intrauterine application the butenyl compound was 10 times as active as progesterone. The butyl and propyl also had high activity, and the ethyl was 1/4 as active as progesterone. The lower members were inactive. With systemic administration the methyl, ethyl, propyl, allyl and butenyl all showed higher activity than progesterone. In the pregnant rabbit, ovariectomized on the 10th day of gestation 19-nortestosterone did not afford any protection. The methyl, ethyl and propyl compounds afforded increasing protection as the length of the side-chain increased, the propyl compound being about as effective as progesterone. The progestational effect of these compounds does not appear to be related to either their androgenic or anabolic activities.