Age-dependent change of serum 5alpha-dihydrotestosterone and its relation to testosterone in man.

Serum 5 alpha-dihydrotestosterone (DHT) and testosterone (T) were measured in 78 normal men aged between 12 and 89 years, separating DHT and T by celite micro-column and using reliable radioimmunoassay. In four age groups of young (20-39 years), middle aged (40-59 years) and old (60-79 years and 80-89 years) men, the mean +/- SEM for serum DHT were 98 + 12, 91 +/- 9, 82 +/- 7 and 54 +/- 15 (ng/100 ml), respectively. The corresponding values for T were 696 +/- 27, 698 +/- 18, 624 +/- 20 and 457 +/- 21 (ng/100 ml). DHT and T showed significant correlation in each age group: r = 0.625, p less than 0.05 (young men), r = 0.727, p less than 0.02 (middle aged men), r = 0.673, p less than 0.05 and r = 0.734, p less than 0.02 (old men), respectively. There was a significant decline in DHT and T levels of 80- to 89-year-age group compared those of 30- to 39-year-age group (p less than 0.05 and p less than 0.005 respectively). But there was no significant changes in DHT and T levels between other age groups. After 3 daily in injections of 4,000 IU human chorionic gonadotropin (hCG) the levels of serum DHT of the young group (20-32 years) and old group (72-78 years) increased 2.6 times and 1.9 times more, respectively. T increased 2.7 times and 1.4 times more, respectively.