AN INVESTIGATION OF THE URINARY METABOLITES AND SECRETION RATES OF ALDOSTERONE AND CORTISOL IN MAN AND A DESCRIPTION OF METHODS FOR THEIR MEASUREMENT

Abstract

ABSTRACT Methods suitable for the estimation of urinary metabolites of aldosterone and of cortisol are described. The excretion of 3H and of 14C in various urinary fractions after the simultaneous injection of 7-3H aldosterone and 4-14C cortisol have been investigated, and the secretion rates of these steroids were estimated. Factors affecting the accuracy of the methods and their suitability for routine use are discussed. Considerable difference was found in the pattern of excretion of 3H and of 14C. In particular, a much larger proportion of the injected tritium was released on extraction at pH. 1. Further, while the total excretion of glucuronide as a percentage of the injected dose was greater for 14C than for 3H, about 72 % of the total tritium in the glucuronide fraction of the first 24 hour urine collection was eluted as a single chromatographic peak, whereas about 60 % of the 14C in the glucuronide fraction was eluted as tetrahydrocortisone, tetrahydrocortisol and allotetrahydrocortisol combined. Excretion values for aldosterone released at pH 1 were obtained for nine normal men after addition of tritiated aldosterone to the urine, and for five normal women and one normal man after injection of the isotope. Excretion values for cortisol metabolites are reported for six normal subjects after injection of 4-14C cortisol. Secretion rates for cortisol were calculated for six normal subjects from the specific activity of the tetrahydro metabolites. The values were 12.2 to 20.5, mean 17.2 mg/d, and agreed with those reported by other workers. The secretion rates for aldosterone, based on the specific activity of the aldosterone released at pH 1 were 50 to 118, mean 77 μg/d.