History and Objectives: Many investigations have evaluated the effects of serum androgen changes on pituitary hormones. In this article, the effect of androgenic therapy on thyroid function test in hypogonadal men were examined.

Materials and Methods: Subjects were chosen among the male patients with clinical signs of hypogonadism. Blood samples were taken for testosterone, thyroxine, triiodothyronine and thyrotropin measurements before and after androgenic therapy. Therapy was carried out for two months.

Results: The mean thyroxine, triiodothyronine, thyrotropin were 8.5±2.09 ?g/dl, 137±38.71 ng/dl and 1.7±1.5 ?U/ml respectively. After the treatment, the means were 7.9±1.9 ?g/dl, for thyroxine, 133±43 ng/dl for triiodothyronine and 1.5±1.3 ?U/ml for thyrotropin. The means of thyrotropin showed significant difference (P<0.05).

Conclusion: This study shows that androgen therapy can suppress thyrotropin production.