Studies of rabbit ovarian contractility using chronically implanted transducers.

A chronically implanted, highly sensitive force transducer was used to study ovarian contractions in the rabbit. The transducer is implanted into the medulla of the ovary through its long axis. The leads are then drawn through the abdominal wall and directed subcutaneously to the back of the neck. The miniature pin connector is fixed into place beneath the skin to facilitate accessibility for repeated recordings, obviating the necessity for anesthesia or serial laparotomies. Intraovarian transducers were implanted in isolated rabbits. Serial recordings of ovarian contractions were made at weekly intervals for 3 weeks, following which ovulation was induced with 100 IU of human chorionic gonadotropin (HCG). Extended recordings were made from 3 through 13 hours after HCG administration to six animals. Recordings revealed increased ovarian contractile activity beginning just before the anticipated time of ovulation. The observations support those of previous acute experiments and demonstrate a relationship between ovarian contractile activity and the process of follicle rupture.