Serum testosterone and dihydrotestosterone changes with age in rat

Serum testosterone (T) and 5alpha-dihydrotestosterone (DHT) were measured in young, adult and old Albino Wistar male rats using a sensitive and reliable radioimmunoassay, after separating T from DHT by thin layer chromatography. The mean plus or minus S.E.M. for T in young, adult and old rats were 62 plus or minus 11, 250 plus or minus 27 and 125 plus or minus 25 (ng/100 ml) respectively. Serum T was increased in adults (P less than 0.001) and decreased in old rats (P less than 0.01). The mean plus or minus S.E.M. for serum DHT was 8 plus or minus 2, 19 plus or minus 2 and 17 plus or minus 1 (ng/100 ml) for young, adult and old rats respectively. DHT was increased in adults (P less than 0.001), but did not change in old rats.