Different testosterone and LH relationships in infertile men.

In both man and animals, changes in Leydig cell structure and function accompany seminiferous tubule damage. In this study of 1745 men attending an infertility clinic, 14% of men with elevated levels of FSH also had elevated LH levels. Groups with severe seminiferous tubule failure (eg, Sertoli Cell Only syndrome or high FSH levels) showed an inverse correlation between LH and testosterone levels. In contrast, groups with milder forms of seminiferous tubule disorders (mild hypospermatogenesis, or FSH levels in the low-normal range) showed a positive correlation between LH and testosterone. It is concluded that different mechanisms must be operative to explain the opposite relationships between LH and testosterone, and that their elucidation may point to the etiology of some forms of seminiferous tubule damage in man.