INHIBITION OF OXYTOCIN-INDUCED LABOUR IN RABBITS WITH VARIOUS GESTAGENS

Abstract

ABSTRACT Progesterone, 17α-methyl-19-nortestosterone, allylestrenol, 6α-methyl-17α-acetoxyprogesterone, and 6-dehydro-retroprogesterone were given parenterally as oily solutions to pregnant rabbits at various periods of time before induction of labour with oxytocin, 30 days + 6 hours after conception. In the inhibition of induced labour, 6α-methyl-17α-acetoxyprogesterone was found to be between 10 and 100 times as active as progesterone, 6-dehydro-retroprogesterone was almost as active as progesterone, while 17α-methyl-19-nortestosterone and allylestrenol were ineffective in the doses given. When allylestrenol was given during the last few days before term to prolong gestation, it was found less effective than progesterone and much less effective than 6α-methyl-17α-acetoxyprogesterone.