Is Spermatogenic Damage Associated with Leydig Cell Dysfunction?

Extract

The two functions of the testis, sperm production and testosterone secretion, are linked to the two anatomical compartments of the testis, the seminiferous tubules and Leydig cells, respectively. This structural partitioning has often led to a functional separation, especially in view of the fact that LH controls Leydig cell secretion of testosterone, which, together with FSH, controls spermatogenesis. The results of the study of Andersson et al. in this issue of the JCEM (1) emphasize that spermatogenic dysfunction is often associated with impaired Leydig cell dysfunction. They showed that between 12 and 15% of men with diminished spermatogenesis had lower testosterone levels or higher LH concentrations than 97.5% of a population of fertile men. Their study provides substantive support for a concept developed from several smaller studies conducted over the past 30 yr. Several studies of men with spermatogenic disorders had identified that, in some men, testosterone levels were frankly below or were close to the lower limit of the normal range and were accompanied by elevated levels of LH (2, 3). The latter group was considered to be in a state of compensated Leydig cell failure (4), a state characterized by a low testosterone to LH ratio, as described by Andersson et al. (1). Further support for subnormal Leydig cell function in these men with spermatogenic damage came from their poor response to human chorionic gonadotropin (hCG) stimulation (5), with those who had the most severely impaired spermatogenesis showing the lowest testosterone response.