Comparison of oviductal transport of fertilized and unfertilized ova after HCG or coitus-induced ovulation rabbits

Location of ova in cleared oviducts was compared in rabbits given HCG (Group I), HCG with artificial insemination (Group II), and in naturally mated rabbits (Group III). Forty-eight hours after the ovulatory stimulus, ova were located significantly deeper in oviducts of Group II than in Groups I and III. By 60 h location of ova in the oviduct was not different between groups. However, at 60 and 66 h a considerable number of ova had entered the uterus in Groups I and II, but not in Group III. By 72 h the majority of ova had entered the uterus in Groups I and II and entry had begun in Group III. The majority of ova did not enter the uterus in Group III until between 78 and 84 h after mating. Sections of oviducts examined histologically indicated that fertilized and unfertilized ova travelled at the same rate in individual rabbits until uterine entry occurred. These data suggest that induction of ovulation by HCG and by mating respectively have different effects on the propulsion or resistance at the uterotubal junction.