Androgen insensitivity in oligospermic men: a reappraisal

Androgen insensitivity has been reported to be present in as many as 40% of patients with severe oligospermia. In order to evaluate further the role of androgen resistance in male infertility we studied 24 men with severe oligospermia. Plasma T and LH were measured by RIA and the T X LH product was calculated. Fibroblasts were grown from genital skin obtained during testicular biopsies and androgen receptor maximal binding capacity (BMAX) and affinity (KD) were measured in fibroblast monolayers. Pubic skin 5 alpha-reductase activity, an androgen-dependent enzyme, was measured in skin homogenates. Plasma T values were in the upper normal range [7.0 +/- 1.7 (SEM) ng ml-1] whereas the T X LH product was high (greater than 50) in only six patients. Mean BMAX and KD values for the androgen receptor were normal [BMAX: 788 +/- 259 fmol mg DNA-1 (patients, n = 20), 726 +/- 227 (normal men, n = 20), and KD: 0.27 +/- 0.24 (patients, n = 20), 0.18 +/- 0.09 (normal men, n = 15), respectively]. However, four men had supranormal KD values. The mean BMAX was also normal when the group of men with sperm densities below 10(6) per ejaculate was considered separately. Public skin 5 alpha-reductase activity was normal in all but four patients (patients: 177.1 +/- 91 fmol/mg skin/h, n = 30, normal men: 210 +/- 45, n = 20 patients). In conclusion, androgen receptor BMAX levels were normal in all patients studied, regardless of the sperm density and the T X LH product. Pubic skin 5 alpha-reductase activity was also normal in all but four patients. In these four patients, a qualitative defect of the androgen receptor cannot be excluded. In this group of patients with severe oligospermia, infertility did not seem to be related to quantitative abnormality of the androgen receptor as was previously reported.