Potassium in Whole Body, Skeletal Muscle and Erythrocytes in Chronic Renal Failure

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Abstract
Intracellular potassium was studied in 11 patients with predialysis chronic renal failure by the use of skeletal muscle biopsies and whole-body counting. For various clinical reasons, therapy was unavoidable in the patient group. 62 healthy subjects in two groups served as controls. Potassium in skeletal muscle was determined by a neutron activation technique. Total body fat (TBF) and lean body mass (LBM) were determined anthropometrically. Total body water (TBW) was determined by isotope dilution and total body hydrogen (TBH) by an in vivo neutron activation technique. Soft fat free solids (SFFS) were calculated from TBF, TBW and TBH. Erythrocyte potassium (EK) and serum potassium (SK) were determined. Intracellular potassium was low in patients with renal failure compared to healthy controls when determined in muscle biopsies (p < 0.01), and by whole body counting, expressed in percent of the predicted value from anthropometricdata (TBK%; p < 0.001) or when expressed as TBK/LBM (p < 0.01) TBK/TBW (p < 0.01) or as TBK/SFFS (p < 0.001). The SK was increased (p < 0.01) although all individual values were within the normal range. No significant differences were found in EK, TBW or in erythrocyte water content between the patients and controls. An inhibitory effect on the sodium potassium ATPase by uremic metabolites and a decrease in cellular potassium capacity are discussed as explanations for the potassium decrease in predialysis renal failure.