The pH of K-deficient muscle

The acid-base balance of muscle from control and K-deficient rats was studied. From the measured buffering capacity, 8–11 mEq excess of anions or deficit of cations would be required to acidify 100 gm fat-free dry weight of muscle, 0.5 pH units. No evidence of increased organic acids, increased anionic equivalence of muscle proteins, or of decreased concentrations of weak bases which are potential cations in cell acidosis was found. This evidence, supplemented with data in the literature, fails to account for the cell acidosis reported in the literature. Reliability of the ‘chloride space’ as a measure of the extracellular phase of muscle in K deficiency has been confirmed by showing its agreement with the ‘raffinose space.’ The cell pH has then been calculated from the distribution of CO2 in muscle (indirect method) and from the pH of muscle homogenates (direct method) in control and K-deficient animals. Control and K-deficient muscle pH's are, respectively, 6.89 and 6.83 by the direct method, and 7.11 and 7.05 by the indirect method.