Oxidative phosphorylation in magnesium and potassium deficiency in the rat

¹ Department of Physiology and Biochemistry, The University of Southampton, Southampton; and Department of Chemical Pathology, Post-graduate Medical School, London, England

Heart sarcosomes were isolated from magnesium-deficient, potassium-deficient, and normal control rats. Two methods of isolation were used. P/O ratios were determined after measuring the oxygen consumption polarometrically in some cases and mano-metrically in others. No matter which method of isolation was used, or which method of determining the oxygen consumption, no difference could be demonstrated between the ratios obtained using sarcosomes isolated from the control rats and those isolated from the magnesium-deficient or the potassium-deficient rats. The results obtained in magnesium deficiency are not in agreement with those reported in 1957 by Vitale, Nakamura, and Hegsted (J. Biol. Chem. 228: 573, 1957), who found lowered P/O ratios were associated with magnesium deficiency. While no satisfactory explanation can be found for the differences reported, it is suggested that they can only be ascribed to differences in technique.