[Studies on intratubular androgens in idiopathic male infertility]

No significant effective therapy has been established for patients with idiopathic male infertility up to now. In order to assess the role of androgens in idiopathic male infertility, testosterone (T) and 5 alpha-dihydrotestosterone (DHT) levels in isolated seminiferous tubules (intratubular levels) were measured by radioimmunoassay (RIA) in 100 patients with idiopathic male infertility. RIA of T and DHT levels in the whole testis (intratesticular levels) were also conducted simultaneously. Seminiferous tubules were separated by a two step incubation system using collagenase and mesh No. 100. 1. Intratubular T levels were higher than intratubular DHT levels with both azoospermia and oligozoospermia. 2. No significant correlations to either intratubular T or DHT levels were present in the plasma LH, FSH, or T levels and the thickness of seminiferous tubular wall. These data suggest that plasma hormones are not the main regulators for intratubular androgens. 3. Moderate correlation between the intratesticular T and intratubular T levels was noted (r = 0.49), but there was no correlation between the intratesticular DHT and intratubular DHT levels (r = 0.33). There was no significant correlation to either intratubular T or DHT as to the testicular volume or the mean germinal epithelium score count method of Johnsen. Therefore, it is considered that the intratubular T level is partially dependent on endogenous T secreted from Leydig cells. However, spermatogenesis may be regulated by various factors including the intratubular T level.