The Metabolic Clearance Rate of Aldosterone in Pregnant and Nonpregnant Subjects Estimated by Both Single-Injection and Constant-Infusion Methods*

Jones and colleagues (1) found that the pattern of urinary metabolites of aldosterone was changed in pregnant compared with nonpregnant subjects. The ratio, however, of the secretion rate to the urinary free aldosterone, which was taken to indicate the over-all metabolic rate, was not appreciably altered. Daughaday (2) and Meyer (3) and their as- sociates found that the binding of aldosterone to plasma proteins other than albumin was the same for nonpregnant and pregnant subjects and for subjects treated with small amounts of estro- gens. The unaltered binding, unlike that of cortisol, might suggest that the over-all metab- olism of aldosterone is unchanged in pregnancy.