PROCEDURE FOR ISOLATION AND DETERMINATION OF HUMAN BLOOD ANGIOTENSIN

Abstract

A method is proposed for the isolation and measurement of blood angiotensin in humans. It involves immediate precipitation of 200 to 400 ml of blood with ethanol, ether extraction, purification by column chromatography on Dowex resin followed by paper chromatography, and detection by a pressor assay in a rat preparation. Recovery of added angiotensin has been quantitative; accuracy varied from 10 to 20%, and sensitivity was 5-10 millimicrograms/100 ml of blood, depending on the amount of blood drawn. The isolated material gave the same pressor response curve in the rat as standard valine-5 angiotensin II, aspartic B-amide; it had the same mobility in two different paper chromatographic systems and in one electrophoretic system. The material was indistinguishable from standard angiotensin eitner infused intravenously in human subjects and subsequently recovered from their blood or added directly to the blood before processing. It is likely that this procedure may also serve to isolate arginine vasopressin.