Biliary excretion of [3H]aldosterone and its sex dependence in adrenalectomized rats.

The rate of excretion of 3-H-radioactivity via the bile into the intestine following intravenous injection of [3-H]aldosterone, was demonstrated to be rapid and sex-dependent in adrenalectomized rats. Within 1 h, female rats excreted into the intesting via the bile greater than 95% of the injected dose of [3-H]aldosterone, compared to 47% in the male rats. In both the male and female rats, greater than 90% of the total radioactivity excreted into the intestine represented dichloromethane nonextractable polar derivatives of aldosterone (NEPD). Similarly, the quantities of NEPD recovered in the bile following bile duct cannulation of the rats, were also sex-dependent. These findings account for the rapidity and sex-dependence of the rates of clearance of aldosterone and its metabolites from the plasma of adrenalectomized rats. The sex hormones appear to influence not only the extent and the routes of metabolism of aldosterone in the liver, but also the rates of clearance of aldosterone and its metabolites from the plasma into the bile.