The effect of dietary sodium on the renal enzyme-pattern of the rat.

Abstract

The relationship between dietary sodium and the activity of representative renal enzymes of the three main metabolic pathways-oxydative breakdown, glycolysis and pentose-monophosphate-shunt-was studied in the rat kidney. Enzyme assays were carried out on total tissue homogenates and isolated mitochondria of the cortex and medulla as well as on isolated glomerula of rats maintained on low or high sodium diet for 14–17 days. While there was no difference in the weight-gain between rats maintained on low sodium food or normal laboratory chow, rats fed high sodium diet put on more weight and had larger kidneys than the other groups. The protein content of the total tissue homogenate followed the same pattern whereas equal amounts of mitochondrial or glomerular protein was found in all three groups. In all preparations both low, and to a greater extent, high dietary sodium increased the specific activity of the majority of enzymes assayed. No fall in the activity of any enzyme could be observed. A number of causal mechanisms are discussed. It is assumed that hyperaldosteronism in the low-sodium group and elevated vasopressin level in rats fed high-sodium diet are responsible for the identical results.