REGRESSION OF CORPORA LUTEA IN UNILATERALLY PREGNANT GUINEA-PIGS

Abstract

SUMMARY Corpora lutea of unilaterally pregnant guinea-pigs regressed in the ovary adjacent to a non-gravid uterine horn while luteal maintenance occurred in the opposite ovary adjacent to a gravid horn. Severence of the utero-ovarian vascular and tissue connexions of the non-gravid uterine horn prevented unilateral regression during unilateral pregnancy and also appeared to cause asynchronous maintenance of cyclic corpora lutea that prolonged the length of oestrous cycles. Unilateral hysterectomy also prevented luteal regression during unilateral pregnancy. One-third of the females in which the vascular and tissue connexions between the ovary and non-gravid horn were left intact did not contain corpora lutea in the ovary adjacent to the non-gravid horn. Most of the remaining females in the same treatment groups contained smaller corpora lutea in the ovary adjacent to a non-gravid horn than in the ovary adjacent to a gravid horn. The presence of a sterile uterine horn tended to cause a decrease in the size of corpora lutea located in the contralateral ovary during the last half of pregnancy.