Poyet P, Labrie F
Mol Cell Endocrinol. 1985 Oct;42(3):283-8. doi: 10.1016/0303-7207(85)90059-0.
Flutamide is approximately 2-fold more potent than cyproterone acetate in reversing the stimulatory effect of dihydrotestosterone (DHT) on ventral prostate weight. Even at the highest dose of cyproterone acetate, prostate weight remains 40% above control while flutamide completely reverses the stimulatory action of DHT, thus suggesting some partial androgenic activity of cyproterone acetate. Megestrol acetate, on the other hand, is devoid of any antiandrogenic activity and it even increases the stimulatory effect of DHT on prostate weight. While flutamide completely reverses the inhibitory effect of DHT on plasma LH levels in castrated animals, cyproterone acetate reverses the value of this parameter by only 30% while megestrol acetate further inhibits plasma LH levels at all the doses used. Both cyproterone acetate and megestrol acetate inhibit adrenal weight to approximately 25% of control, thus indicating their glucocorticoid activity. As direct measure of androgenic activity, cyproterone acetate and megestrol acetate increased prostate weight in castrated animals by 60 and 100%, respectively (P less than 0.01) while flutamide had no effect. The present data show that cyproterone acetate and megestrol acetate, in addition to their well-known progestational and glucocorticoid action, have intrinsic androgenic activity. Since it is the only compound having pure antiandrogenic activity, flutamide provides the best scientific arguments for its successful use for the treatment of androgen-sensitive diseases.
氟他胺在逆转二氢睾酮（DHT）对前列腺腹侧重量的刺激作用方面，效力比醋酸环丙孕酮约强2倍。即使使用最高剂量的醋酸环丙孕酮，前列腺重量仍比对照组高40%，而氟他胺能完全逆转DHT的刺激作用，这表明醋酸环丙孕酮具有一定的部分雄激素活性。另一方面，醋酸甲地孕酮没有任何抗雄激素活性，甚至会增强DHT对前列腺重量的刺激作用。虽然氟他胺能完全逆转DHT对去势动物血浆促黄体生成素（LH）水平的抑制作用，但醋酸环丙孕酮只能使该参数值逆转30%，而醋酸甲地孕酮在所有使用剂量下都会进一步抑制血浆LH水平。醋酸环丙孕酮和醋酸甲地孕酮都能将肾上腺重量抑制至对照组的约25%，这表明它们具有糖皮质激素活性。作为雄激素活性的直接衡量指标，醋酸环丙孕酮和醋酸甲地孕酮分别使去势动物的前列腺重量增加了60%和100%（P小于0.01），而氟他胺则没有效果。目前的数据表明，醋酸环丙孕酮和醋酸甲地孕酮除了具有众所周知的孕激素和糖皮质激素作用外，还具有内在的雄激素活性。由于氟他胺是唯一具有纯抗雄激素活性的化合物，因此它为成功用于治疗雄激素敏感性疾病提供了最佳的科学依据。
