Testosterone and 5alpha-androstan-17beta-ol-3-one (DHT) levels in man.

In order to test the hypothesis that plasma 17beta-hydroxy-5alpha-androstan-3-one (DHT) levels might represent a parameter of androgenicity independent of testosterone (T) levels, the T/DHT ratio was determined at low and high T levels in both sexes. High T levels in males were obtained either by stimulation of endogenous T secretion, but im injection of either short or long-acting T esters and finally by oral administration of 200 mg of crystalline testosterone. In females high T levels were obtained either by im injection of long-acting T esters or by oral administration of 200 mg of T. It was observed that the T/DHT ratio was not a function of sex but a function of T levels, whether T had an endogenous or a exogenous origin. When, as in patients with porto-caval shunt or cirrhosis of the liver, the liver was bypassed, oral administration of T resulted in relatively higher DHT levels than expected from T levels: this suggests an extra-hepatic origin of plasma DHT and/or a decreased hepatic metabolism of DHT. In a patient with the testicular feminization syndrome the T/dht ratios both under basal conditions and after im injection of T propionate were similar to those observed in normal subjects.