Abstract
In 24 conscious unilaterally pregnant rabbits the spontaneous and oxytocin-induced uterine activity was recorded by either one or two sponge-tipped catheters placed in each horn. In the pregnant horn the catheters were placed between the fetal membranes and the uterine wall. The recordings were repeated daily during the last days of pregnancy, for 4 to 8 days post partum, and thereafter at longer intervals for up to several weeks. The pregnant horn was consistently more active and more sensitive to oxytocin than the sterile horn up to about 1 week after delivery, when the difference disappeared. Intravenous vasopressin injections up to 0.05 IU did not increase the activity in either horn.