Endocrinological studies with desogestrel.

13-Ethyl-11-methylene-18,19-dinor-17 alpha-pregn-4-en-20-yn-17-ol (Org 2969, desogestrel) is a new progestational steroid which has been developed for application in oral contraceptives. In assays for characteristic progestational effects (McPhail test, McGinty test, Deciduoma test and Antifertilization test) and in tests for inhibition of ovulation, desogestrel is highly active after oral administration and more potent than the structurally related reference compounds norethisterone and levonorgestrel. The same holds for its anti-oestrogenic activity.