The Renal Lesions in Experimental Deficiency of Potassium

Abstract

Renal lesions similar to those observed in chronic intestinal disease in man may be produced in rats by use of diets that are deficient in K. These experimental lesions differ from those observed in man chiefly in the degree of vacuolation, which is more intense in man. When weanling rats were fed synthetic diets that were deficient in K and were given triple-distilled water, it became evident that K is necessary for the proper growth and development of the rat. During the first 2 weeks of the study, the control animals maintained on a balanced diet gained an average of 74, g more than double their initial weights, whereas animals that were eating the K-deficient diet gained only 6 g approximately a tenth of their initial weights. The weights of the kidneys of the K-deficient rats were more than those of the normal controls, although their total body weights were less. A distinctive lesion involving the entire nephron was produced by deprivation of K. This lesion consisted of dilatation of tubules, with necrosis of the parenchyma and vacuolation of the cytoplasm. These lesions progressed in severity from the glomerulus to the distal collecting tubules, the most advanced lesions occurring in the latter location. Most of the lesions that developed in the various portions of the nephron were gradually reversed by restoration of K to the diet. The glomerular lesions disappeared first, then those of the proximal convoluted tubules, and finally those of the distal tubular system, which required approximately 3 weeks after K was restored to the diet. Deposits of Ca within the lumens of the tubules and complete fibrosis of an occasional glomerulus were not reversed by the addition of K to the diets; such changes indicate permanent damage.