Danazol Inhibits Steroidogenesis

Danazol was found to inhibit multiple enzymes of steroidogenesis directly in the pregnant mare serum (PMS)-treated hamster ovary and the rat testis and adrenal in vitro. In the PMS-treated hamster ovary, danazol inhibited 17α-hydroxylase, 17,20-lyase, and 3β-hydroxysteroid dehydrogenase. In the rat testis, danazol inhibited 17α-hydroxylase, 17,20-lyase, 3β-hydroxysteroid dehydrogenase, and 17β-hydroxysteroid dehydrogenase. In the rat adrenal, danazol inhibited 3β-hydroxysteroid dehydrogenase, 21-hydroxylase, and 11β-hydroxylase. Two hours after a subcutaneous injection of 5 mg/kg of danazol to adult male rats, serum luteinizing hormone levels were significantly increased and serum testosterone levels were significantly suppressed. These findings suggest that in the rodent one of danazo’s major pharmacologic effects is the direct inhibition of steroidogenesis.