AGING ABOLISHES THE RENAL RESPONSE TO L-ARGININE INFUSION IN ESSENTIAL-HYPERTENSION

A defect in the endothelium-dependent vasorelaxation could contribute to the development of arterial hypertension through the facilitation o f renal vasoconstriction and sodium retention. In this study, we teste d the hypothesis that aging impairs kidney function in essential hyper tension through a derangement of nitric oxide-dependent renal mechanis ms. To this end, we compared the renal response to an intravenous infu sion of the precursor of nitric oxide synthesis, L-arginine, in young and aged essential hypertensives. In young hypertensives, L-arginine i nduced a significant increase in renal plasma flow, glomerular filtrat ion rare, natriuresis and kaliuresis, without changes in filtration fr action. These effects were not observed in aged hypertensives. Neither PRA nor PA were affected by L-arginine infusion in any group. These r esults indicate that aging produces a derangement of endothelial funct ion in essential hypertension.