THE DETERMINATION OF ALDOSTERONE IN URINE*†

Abstract

A procedure for determination of aldosterone in a 24-hour sample of urine is described. The aldosterone conjugate in urine is hydrolyzed with acid, the free steroids are extracted with chloroform, and the aldosterone is separated from the other steroids by successive chromatograms in (1) formamide-chloroform, (2) form-amide-butyl acetate-water, and (3) ethyl acetate-toluene-benzene-water. The quantity of aldosterone present is estimated from the intensity of both the blue spots and the yellow fluorescent spots that are obtained by appropriate treatment of the final chromatogram with alkaline blue tetrazolium. A determination requires three days. Normal values range from 2 to 16 [mu]g. per twenty-four hours, and recoveries of 5-[mu]g. to 10-ug. quantities are 80 to 90 per cent. Dilute acetic acid acts as a preservative for samples of urine that cannot be refrigerated. Various factors that affect the determination are discussed.