[Contraceptive activity and mechanism of action of combinations of 6-methyl-substituted D'6-pentaranes and mestranol].

It has been shown in experiments on rats, mice and rabbits that 6 alpha-methyl-16 alpha, 17 alpha-cyclohexano-pregna-4-en-3, 20-dion and 6-methyl-16 alpha, 17 alpha-cyclohexano-pregna-4,6-dien-3,20-dion belonging to the series of D'6-pentaranes exhibit high contraceptive activity when combined with mestranol. The contraceptive activity of D'6-pentaranes combined with mestranol arises primarily from their inhibitory effect on luteinizing function of the hypophysis.