Influence of sex, testicular development and liver function on the bioavailability of oral testosterone.

The bioavailability of orally administered testosterone was investigated in normal and hypogonadal men, prepubertal boys, normal women, and in patients with fatty liver, liver cirrhosis and surgical portocaval shunts. Peripheral testosterone concentrations remained unchanged in normal men and men with fatty liver, whereas a steep increase was observed in all other groups. The greatest increase was seen in patients with compensated liver cirrhosis and with portocaval shunts. The steep increase of peripheral testosterone in boys, women and hypogonadal men is attributed to their having a lower activity of androgen-metabolizing liver enzymes than normal men. The increase in patients with cirrhosis is most likely caused by intra- and extra-hepatic portocaval shunts.