Hysterectomy of pseudopregnant rats consistently increased the duration of vaginal dioestrus and the interval between ovulations. These observations suggested that the presence of the nongravid rat uterus limits the life span of pseudopregnancy corpora lutea.
Neither aqueous nor ether extracts of bovine endometrium collected at several stages of corpus luteum function significantly affected the life span of corpora lutea in hysterectomized pseudopregnant rats.
Vasopressin decreased the duration of vaginal dioestrus and hastened ovulation in hysterectomized, but not in intact, pseudopregnant rats, suggesting that it hastened luteal regression after hysterectomy.
Oxytocin failed to shorten the period of luteal function in the hysterectomized rat. Ovarian weight in intact and hysterectomized rats was increased by this means.