Danazol is an isoxazol derivative of the synthetic steroid, 17 alpha-ethinyltestosterone (ethisterone). Intragastric administration of danazol (10 mg/100 g body weight) markedly reduced plasma levels of luteinizing hormone and testosterone, and the number of S-phase cells labelled with bromodeoxyuridine (BrdU) in the submaxillary glands which were androgen-dependent in adult male rats. These results demonstrated that danazol might show a potency as antiandrogenic and/or antigonadotrophic agent.