A Pressor Agent in Human Stable Plasma Protein Solutions

Abstract

A pressor material in human stable plasma protein solutions is described, and evidence that this material may be angiotensin II is presented. When six samples of stable plasma protein solution were assayed against standard angiotensin in the sensitive, ganglioplegic, nephrectomized rat anesthetized with urethane, the levels of pressor activity ranged from 320 to 830 ng/100 ml, with a mean of 552 ng/100 ml. The solution gives a pressor response similar to that of angiotensin II, is heat stable, dialyzable, and destroyed by trypsin and α-chymotrypsin, and reacts with the antibody in a radio-immunoassay for angiotensin II. It is present in sufficient concentration to have significant effects on blood pressure, renal handling of sodium, and aldosterone secretion when infused into patients at rates commonly employed.