EFFECT OF SODIUM RESTRICTION AND EXPERIMENTAL NEPHROSIS ON TISSUE SPACES AND TISSUE SODIUM DISTRIBUTION IN THE RAT

Abstract

SUMMARY Aldosterone secretion is increased in rats on a diet low in sodium content or in rats with nephrosis induced by administration of an aminonucleoside. Distributions of water and sodium in heart, liver, adrenals and abdominal muscle were compared in nephrotic rats, sodium-restricted rats and rats maintained on a normal diet. In nephrotic animals total tissue sodium increased significantly in liver, heart and abdominal muscle and was associated with increased intracellular sodium (both absolute amount and concentration) in these tissues as well as in the adrenals; extracellular sodium decreased in heart and adrenals and increased in abdominal muscle. In nephrotic rats increased total tissue water in liver and abdominal muscle was associated with increased extracellular water while increased total water in adrenals was accompanied by increased intracellular water. The results in sodium-restricted rats were similar to those in nephrotic rats except that no changes were found in abdominal muscle and that water content of liver was unchanged.