Influence of age on metabolism of testosterone, dihydrotestosterone, and 3-α-androstanediol in muscle biopsies from patients with neuromuscular diseases

We investigated the possible effect of age on the metabolism of androgens in muscle biopsies from patients with neuromuscular diseases. The conversion of testosterone, dihydrotestosterone (DHT) and 5-α-androstane-3-α-17-β-diol (3-α-androstanediol) was measured in muscle biopsies from 24 patients with neuromuscular diseases and seven controls. The reductive metabolism of 3-α-HSDH was significantly higher than the oxidative metabolism. Significant metabolism of testosterone to DHT was not found. Only the age of the patients emerged as a significant negative predictor in a stepwise multiple linear regression model for Vmax and Km (Lineweaver–Burke plots) of the reductive metabolism of 3-α-HSDH. Therefore, altered metabolism of anabolic androgens in skeletal muscles could be demonstrated. We conclude that this could alter the androgenic catabolic/anabolic balance in the (androgenic target organ) skeletal muscle.