Effect of converting enzyme inhibition by enalapril on sodium homeostasis in the rat.

The effect of oral treatment with the converting enzyme inhibitor enalapril on sodium homeostasis was investigated in the rat. Treatment by enalapril prior to and during a 6 day period following abrupt suppression of dietary Na+ was associated with a sodium wasting state (urinary Na+ always exceeded intake during the observation period) and blunting by 90% of the aldosterone response to Na+ restriction In rats on chronic low Na+ intake, enalapril produced a slight, transient natriuresis together with a marked increase in drinking volume. In Na+ replete rats, enalapril had no influence on sodium balance. Converting enzyme inhibition markedly impaired the systemic and renal response to Na restriction and enalapril had no natriuretic effect in the Na+ replete state.