Effect of low electrolyte feeding on development of potassium deficiency.

Abstract

Rats fed a diet deficient in sodium, potassium and chloride were observed for 3, 6, 12, 28, 60 and 110 days. Urine excretion of these ions was observed during the initial adjustment to the diet. Serum and muscle electrolyte composition was determined at the end of each interval. Initially the loss of sodium and chloride constituted a loss of extracellular volume without change in concentration. The loss of potassium in this period resulted in a decrease in the intracellular concentration of potassium. Subsequent conservation of all three substances was very effective. No alkalosis developed during the first 28 days on the deficient diet despite an 18% reduction in muscle potassium concentration. A minimal increase in muscle sodium concentration was observed at this level of potassium deficiency. Evidence indicates that this minimal increase was not a function of the low sodium intake per se but rather was characteristic of the magnitude of potassium deficiency, since a similar minimal increase in muscle sodium occurs when an adequate sodium intake is provided.