Effect of saralasin on plasma renin activity and arginine-vasopressin in hypertensive man

Abstract

This study was carried out to assess the influence of saralasin (SAR), an angiotensin II-analogue, on peripheral and central angiotensin II-receptors by measurements of plasma renin activity (PRA) and arginine-vasopressin (AVP) release. Before and during i.v. infusion of 10 microgram/kg/min of SAR over a 30 minute period, blood samples were obtained from 15 recumbent hypertensive patients (7 renovascular, 8 essential) to determine hormone activities by radioimmunoassay. In 10 patients with a decrease of blood pressure following SAR, PRA increased significantly whereas AVP levels increased significantly in only 7 of these patients. In the remaining 5 patients without a fall of blood pressure, PRA and AVP remained virtually unchanged. The results indicate that an enhanced AVP release may be due to a hypotensive stimulus induced by SAR in angiotensinogenic hypertension. A direct influence of SAR on central receptors is unlikely under the conditions studied.