The study of ovulation in the isolated perfused rabbit ovary. 1. Methodology and pattern of steroidogenesis

A previously described technique for perfusion of the isolated rabbit ovary in a recirculating system (Ahrén et al., 1975) was modified for studies of preovulatory follicular development and ovulation. Follicular ruptures were induced either by injection of human chorionic gonadotropin (hCG) to the animal 5-6 h prior to perfusion or by adding luteinizing hormone (LH) directly to the medium during perfusion. Ovulation occurred 9-14 h after hCG injection in vivo and 7-13 h after the addition of LH in vitro. Ovulations did not occur unless the ovaries were stimulated by gonadotropin in vivo or in vitro. The patterns of release of estradiol-17 beta and progesterone into the medium are consistent with the measurements reported by others on these steroids in ovarian venous blood in vivo. This experimental model is likely to be useful in further exploration of the physiology, biochemistry and anatomy of ovulation.