INHIBITION AND SYNCHRONIZATION OF MATING IN THE MOUSE BY ORAL ADMINISTRATION OF PROGESTINS

Abstract

Diets containing either progesterone or 6a-methyl-17a-hydroxyprogesterone acetate were fed to 95 adult female mice. Mating was inhibited in all cases. Inhibition was effective after a preliminary treatment period of 4 days and extended beyond end of treatment for at least 64 hours. Of the 80 mice which did mate, 71 mated 64-72 hours after normal diet was resumed and the 9 others mated 24 hours later. Eighty-nine per cent of the mice which mated were pregnant when autopsied 12 days after mating. The pregnant females had a mean of 10.4 living fetuses each. Ingestion of treated diets by males did not affect their fertility or libido.