INCREASED GLOMERULAR-FILTRATION RATE AFTER CONVERTING-ENZYME INHIBITION IN ESSENTIAL HYPERTENSION

To test the influence of an inhibitor of angiotensin-converting enzyme, teprotide (SQ 20881), we administered it to seven patients with essential hypertension and normal renal function and nine with an unequivocal reduction in creatinine clearance, caused by bilateral renal-artery stenosis in two and by essential hypertension in seven. Despite the fall in blood pressure (112.7±4.5 to 100.3±3.9 mm Hg, mean ± S.E.M., P<0.01), there were prompt increases in both creatinine clearance (95.9±10.5 to 109.9±9.5 ml per minute per 1.73 m2 of body-surface area, P<0.01) and sodium excretion (17.0±5.9 to 31.7±7.2 μmol per minute, P<0.01) in patients with essential hypertension. The increase in glomerular filtration rate was most striking, averaging 33 per cent (66.0±10.3 to 88.0±9.2 ml per minute per 1.73 m2, P<0.001) in patients in whom an initial reduction was evident and hypertension was more severe. These observations suggest that a functional element, perhaps involving angiotensin-mediated renal vasoconstriction, frequently has a role in the reduction in glomerular filtration rate that occurs in essential hypertension. This class of agent may improve renal excretory function as it controls hypertension. (N Engl J Med 301:9–12, 1979) REDUCED renal blood flow and glomerular filtration are common in essential hypertension,1 but the causes for the reduced filtration rate are unknown; candidates include fixed changes in the afferent arterioles or glomeruli,2 a functional change in the reactivity of the vessels3,4 and an increase in the action of local vasoconstrictors.4 One way to assess the contribution of functional factors to vascular tone rests on the premise that an appropriate drug will quickly reverse the abnormality. This approach has been used, for example, to demonstrate a functional abnormality of the renal blood supply in essential hypertension.4 Few medical phenomena have been. © 1979, Massachusetts Medical Society. All rights reserved.