The pH of K-deficient muscle

Abstract

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.

The Role of Chloride in Hypokalemic Alkalosis in the Rat*

“…Recent studies, however, failed to demonstrate intracellular acidosis in potassium-deficient muscle (7) and showed that anions and cations other than potassium and sodium play a role in cellular pH regulation (6). In the present studies the sum of intracellular potassium and sodium of potassium-deficient muscle was smaller than that of normal muscle only in experiment IA.…”

“…Disappearance of plasma abnormalities following the acute administration of potassium chloride to nephrectomized potassiumdeficient rats (2) seemed to support this hypothesis, as did the finding by some investigators (3)(4)(5) of a decrease of intracellular pH in potassiumdeficient compared with normal skeletal muscle. Other workers, however, failed to find evidence of intracellular acidosis in potassium-deficient muscle (6,7).…”

“…Potassium-deficient animals (group 1) exhibited a hypokalemic, hypochloremic alkalosis (Table V). Acute administration of potassium chloride, 6 mmoles per kg body weight, after functional nephrectomy 4 hours before sacrifice (group 2) resulted in partial correction of plasma and tissue electrolyte changes. The average increase in intracellular muscle potassium content of 6.5 mEq per 100 g FFDS approximately agrees with the rise expected if all of the administered potassium had entered the muscle cells.…”

“…5 In another experiment in three groups of rats exactly similar to those described in experiment III the following values for the inulin space were obtained (g per 100 g FFDS, mean±SD): group 1 (4 rats), 83 ± 4; group 2 (6 rats), 83 ± 5; group 3 (4 rats), 81 ± 4. 6 Individual values for all animals were calculated as potassium and sodium contents of 1 kg fat-free wet carcass minus those of 0.5 kg fat-free wet muscle. Hypochloremia in potassium deficiency could be an expression of chloride deficiency, or the result of expansion of extracellular fluid volume (18), or a combination of these two (8).…”

Measurement of Intracellular pH of Skeletal Muscle with pH-sensitive Glass Microelectrodes*

“…Other investigators (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), however, using either * Submitted for publication August 19, 1965; accepted February 17, 1967. Supported in part by grants 5 TI AM-5028 and 5 TI HE-5469 from the National Institutes of Health.…”