Electrolyte content and ultrastructure of the kidney in hamsters with heart failure

Abstract

Electrolyte (Na, K, Ca, Mg) concentrations were measured in the urine, serum, and renal tissues of cardiomyopathic (BIO 14.6) hamsters, during various stages of spontaneous congestive heart failure, and correlated with ultrastructural changes in renal tubules. The renal concentration of sodium was significantly elevated during the very early (subclinical) stages of congestive heart failure. Further increases paralleled the progress of the disease. The derived data indicate an intracellular location for the augmented load of sodium in the kidney. The magnesium concentrations in the kidney remained unchanged and the variations in renal potassium proved to be significant only during the advanced stages of cardiocirculatory insufficiency. Young cardiomyopathic hamsters had low renal calcium concentrations in spite of elevated serum calcium levels. However, during the terminal phase of congestive heart failure, the calcium values in the kidneys of cardiomyopathic hamsters were higher despite lower serum calcium values. The proximal and distal convoluted tubules as well as the cortical collecting tubules during severe congestive heart failure were characterized by marked widening of the extracellular spaces between the basilar interdigitating processes. The distal convoluted tubules exhibited edema and mitochondrial alterations and the intercellular spaces of the collecting tubules were dilated. These tubular changes indicate an increased flow of water and ions.