Plasma Angiotensinase Activity in Hypertensive Patients

THE DESTRUCTION of angiotensin is believed to result from the action of one or several enzymes which have been called angiotensinase.^1,2 Although a specific angiotensinase has not been identified, angiotensinase activity has been demonstrated in a number of tissues including plasma, the red blood cell (RBC), kidney, liver, and intestine.^1,2 Hickler et al³ reported elevated plasma angiotensinase activity in patients with renal hypertension or edema and postulated that plasma angiotensinase activity may increase in response to increases in renin and angiotensin production by a process of enzymatic adaptation. If this be true, then plasma angiotensinase may play an important role in circulatory homeostasis functioning as part of a mechanism to maintain a normal or as near normal blood pressure as possible in the face of changing concentrations of circulating renal pressor substances. Also by reflecting renin or angiotensin production, measurements of plasma angiotensinase could be used as