RENAL RESPONSE TO AMINO-ACID INFUSION IN ESSENTIAL-HYPERTENSION

In the present study, we evaluated the renal response to a 4-hour infu sion of amino acids in essential hypertensive patients, as well as the effects that dietary sodium restriction and enalapril (a converting e nzyme inhibitor) had on this renal response. During normal sodium inta ke, amino acid infusion significantly increased renal plasma flow from 383+/-58 to 478+/-51 mL/min and glomerular filtration rate from 82+/- 8 to 100+/-13 mL/min. All these effects were abolished when the patien ts received a low sodium diet (40 mmol/d) for 3 days before the amino acid infusion. The administration of enalapril to the patients during sodium restriction restored the amino acid-induced increment in renal plasma flow (from 388+/-35 to 537+/-48 mL/min) and glomerular filtrati on rate (from 88+/-9 to 103+/-10 mL/min). Mean arterial pressure remai ned unaltered under all experimental conditions. The results show that in patients with essential hypertension dietary sodium restriction pr events amino acid-induced increments in glomerular filtration rate and renal plasma flow and that this effect is restored during the simulta neous administration of enalapril.