[Effect of intravenous sodium chloride load on levels of atrial natriuretic peptide (ANP) and 3'5' guanosine monophosphate (cGMP) in plasma of patients with uncomplicated sodium-sensitive arterial hypertension maintained on different dietary sodium intake].

The aim of this work was an evaluation of the effect of the acute hypervolemia induced by 90 min intravenous infusion of 1500 ml 0.9% NaCl (16.7 ml/min) on blood pressure, plasma concentration of the atrial natriuretic peptide (ANP), cyclic guanosine monophosphate (cGMP), aldosterone (ALDO), plasma renin activity (PRA) in patients with essential hypertension on the normal, low and high sodium intake. Twelve patients with noncomplicated essential sodium-sensitive arterial hypertension participated in the study. Sodium chloride infusions were performed three times: first--on the fifth day of normal daily sodium u intake (110-120 mmol/day), second--on the fifth day of low sodium intake (10-20 mmol/day), third--on the fifth day of high sodium intake (200-220 mmol/day). Acute intravenous sodium chloride load induced a significant increase of the mean arterial pressure (MBP) only when the patients were on the high sodium diet. This increase of the MBP was associated with a significantly lower increment of plasma ANP, cGMP, lower decrement of ALDO and PRA when compared to normal- or low- sodium intake. The results suggest an impairment of the adaptive homeostatic mechanisms induced by an acute intravenous sodium load in patients with noncomplicated salt-sensitive essential hypertension ingesting high-sodium diet.