Procedure for Determination of Aldosterone in Human Peripheral Plasma by Double-Isotope Derivative Assay, and Its Application for Measurement of Secretory Rate and Urinary Excretion

Abstract

This is a report of a procedure for the determination of peripheral plasma aldosterone, in which 14C-labeled aldosterone serves as the marker, and the acetylating agent is relatively inexpensive tritium-labeled acetic anhydride of high specific activity. A new method for the chromatographic purification of aldosterone and aldosterone diacetate is presented. This procedure provides a better separation of these two compounds from the unlabeled and labeled impurities.

A decreased metabolic clearance rate of aldosterone in benign essential hypertension

“…Without this precaution, the free aldosterone or its diacetate is often modified by the alcohol. The normal range for peripheral plasma aldosterone in 20 normal subjects was 1.4-16.0 ng/100 ml (mean 7.49, SD ±4.84, SE ±1.08) corrected for blank (22) in recumbent position and on a diet containing normal amounts of sodium.…”

“…0.5 ml of ethanol containing 50 jug of carrier aldosterone and about 300 dpm of a 'C-labeled aldos-terone indicator was mixed with 10 ml of plasma and 0.5 ml of 1 N NaOH in a 100 ml cylinder fitted with a ground glass stopper. The mixture was then extracted once with 7 volumes of dichloromethane (22). After evaporation of the solvent, the dried extract was applied to a thin layer of silica gel (22) and chromatographed in methanol-toluene 15:85.…”

“…The mixture was then extracted once with 7 volumes of dichloromethane (22). After evaporation of the solvent, the dried extract was applied to a thin layer of silica gel (22) and chromatographed in methanol-toluene 15:85. The carrier aldosterone was located under 254 m/A ultraviolet lamp, the spot was cut out and eluted with methanol.…”

“…The procedure used was developed in this laboratory and reported in detail earlier (22). It is a double-isotope de-rivative assay that uses aldosterone-1'C as marker and acetic anhydride-'H with high specific activity as acetylating agent.…”

“…The secretion rate of aldosterone was determined by the double-isotope dilution method (22). Aldosterone-0H (2UCi, 5 Ci/mole) was injected into the antecubital vein.…”