IMPLANTATION AND EARLY PREGNANCY IN OVARIECTOMIZED GUINEA-PIGS

Abstract

Summary. Ovo-implantation in the guinea-pig on the 6th to 7th day post coitum is not affected by ovariectomy on days 3 to 7 p.c. If the ovaries are removed on the 2nd day after mating, however, implantation does not occur unless at least one injection of progesterone is given. In the ovariectomized guinea-pigs, the embryos develop normally for several days but may regress after day 14 unless progesterone is supplied, permitting further growth. No evidence was found of delayed implantation.