Prevention of cystic ovary induction in rabbits by aminoglutethimide

Polycystic ovaries were induced in thyroidectomized rabbits by the administration of either 25 IU human chorionic gonadotrophin or 10 IU pregnant mare serum daily for a period of 20 days. Cystic ovaries in rabbits exhibited subnormal (P < 0.01) ovarian delta 5-3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) concentration and specific activity. Since weight of cystic ovaries was markedly elevated, however, total capacity for delta 4-3-ketosteroid production was enhanced. Concomitant administration of chorionic gonadotrophin and aminoglutethimide phosphate to thyroidectomized rabbits prevented the formation of cystic ovaries indicating that a steroid, or steroids formed beyond cholesterol in the biosynthesis pathway is necessary for the experimental induction of cystic ovaries in this laboratory animal.