Generation and survival of angiotensin in nonrefrigerated plasma. An explanation for presence of pressor material in human plasma protein solutions used clinically.

Abstract

In a previous report a pressor agent was described in a human stable plasma protein solution (SPPS) used clinically as a volume expander, 12 and evidence was presented that this agent was angiotensin. SPPS is prepared by Commonwealth Serum Laboratories (Melbourne) from the plasma fraction of out‐dated donor blood (Red Cross Blood Banks). This plasma is transported to Melbourne from centers up to 2,000 miles away, a proportion of it reaching ambient temperature prior to arrival. Cold ethanol fractionation to yield the albumin fraction is followed by heating for 10 hours at 60 C. The levels of renin, rerun substrate, angiotensin and angiotensinase activity were measured in donor plasma held at 4 C, plasma pool (after transport to Melbourne), and in the SPPS fraction before and after heat treatment. Results suggest that angiotensin is generated in the plasma pools while at ambient temperature. The generated angiotensin is relatively resistant to destruction by endogenous angiotensinases in plasma (in vitro) when compared with angiotensin‐II‐amide (Hypertensin, Ciba). The presence of concentrations of angiotensin sufficient to affect the blood pressure and aldosterone secretion of human recipients should be suspected in plasma (or plasma products) the preparation of which includes a period at ambient or higher temperature.