[The renin-angiotensin system and renal adaptation to sodium restriction]

The renin angiotensin aldosterone system (RAAS) is activated during the early phase of renal adaptation to sodium restriction. The effect of the converting enzyme inhibitor (CEI) MK 421 (MK) was studied when administered 3 days before and 6 days after sodium restriction. Mean arterial pressure, variations of urinary aldosterone, renal blood flow and sodium balance were studied. The results are the following; (Formula: see text) Those results demonstrate that CEI is associated with a renal inadaptation to sodium restriction. Other studies demonstrate that this disequilibrium persists during the second week of treatment in the rat. Those results may be related to an inhibition of aldosterone effect during the sodium restriction, a renal vasodilatation or an accumulation of kinin and endogenous prostaglandins. In summary, a functional RAAS is necessary during the functional adaptation to a sodium restriction. The renal prostaglandins stimulation may contribute to the disequilibrium balance in association with the CEI administration.