ARITAKI, S., MIYAZAWA, H., OGIHARA, M., USHIO, M. and IZUMIZAWA, A. An Endocrinological Study of Persistent Pubertal Macromastia. Tohoku J. Exp. Med., 1992, 167 (3), 189-196-We performed an endocrinological study on three males with persistent pubertal macromastia. The blood testosterone (T) level in these patients was either elevated or at the upper normal limit, estrone (E₁) and estradiol (E₂) levels were high, and T/E₁ and T/E₂ ratios were decreased. Persistence of low T/E₁ and T/E₂ ratios was thought to be the cause of the macromastia. Results of therapy using drugs (cyproterone acetate, tamoxifen citrate, danazol, and clomiphene citrate) were unsatisfactory. Persistent pubertal macromastia is an extreme condition of physiological pubertal gynecomastia, a transient phenomenon in more than half of pubertal males. It is a pathological condition characterized by a great degree of breast enlargement and abnormal endocrinological findings, and its clinical course and treatment are different from those of physiological pubertal gynecomastia.