CALCULATION OF INTRACELLULAR pH FROM THE DISTRIBUTION OF 5,5-DIMETHYL-2,4-OXAZOLIDINEDIONE (DMO). APPLICATION TO SKELETAL MUSCLE OF THE DOG*

Abstract

The theory of estimation of intracellular pH by means of measurement of the distribution of weak organic acids and bases is discussed. DMO has properties almost ideal for this purpose. The distribution of DMO was used to measure the intracellular pH of skeletal muscle of the dog under various conditions. The intracellular pH of normal, resting muscle averaged 7.04. The greatest changes of pH muscle are those produced by raising the CO2 tension of blood. The pH of muscle is lowered by a high tension of CO2 whether or not the blood pH is lowered. Metabolic acidosis has less effect in lowering muscle pH than does high tension of CO2. Respiratory and metabolic alkalosis raise muscle pH only to a small extent.