EFFECT OF 5-ALPHA-REDUCTASE INHIBITION ON SEX-HORMONE-BINDING GLOBULIN IN ELDERLY MEN

In this study we examined the possibility that chronic reduction in se rum dihydrotestosterone (DHT) attained by pharmacologic inhibition of 5 alpha-reductase modulates serum sex-hormone-binding globulin (SHBG) levels in elderly men. Twenty-one men, ages 58-79 years (mean 66) with benign prostatic hypertrophy were treated with the 5 alpha-reductase inhibitor finasteride (5 mg daily) for 12 months. Serum DHT declined b y 80% (p < 0.001) and total testosterone rose by 14% (p < 0.05). Serum SHBG concentration remained unchanged (44.1 +/- 4.5 vs 45.2 +/- 5.7 n mol/l for pre- and post-therapy levels, respectively). Thus, the conve rsion of testosterone to DHT is not required to maintain the androgeni c effect on serum SHBG concentration in elderly men.