Effect of Furosemide Administration and Upright Position on Plasma Renin Activity and Angiotensin II in Hypertension

Abstract

Both plasma renin activity and angiotensin II during recumbency measured by radioimmunoassay, were normal in essential hypertension, chronic glomerulonephritis and bilateral renal artery stenosis, definitely low in primary aldosteronism, and high in unilateral renal artery stenosis. In normal subjects upright posture and furosemide administration induced an elevation in plasma renin activity; which correlated directly with the elevation in angiotensin II. In general, the increase in plasma renin activity was much larger than that in plasma angiotensin II. Plasma renin activity and angiotensin II did not increase in primary aldosteronism, while markedly increased in unilateral renal artery stenosis during upright posture with furosemide administration. The response of plasma renin activity and angiotensin II in essential hypertension and chronic glomerulonephritis was essentially similar to that observed in normal subjects. The suppression of plasma renin activity is uniquely diagnostic of an aldosterone-secreting adrenal tumor. Similarly, the enhancing effect on plasma renin activity and angiotensin II of the upright position might be a good index for the diagnosis of renovascular hypertension. Our data indicate that the changes in plasma renin activity and angiotensin II are due to changes in the amount of the renin rather than to changes in other elements of the renin-angiotensin system. © 1973, Tohoku University Medical Press. All rights reserved.