Red Cell 2,3-Diphosphoglycerate and Intracellular Arterial pH in Acidosis and Alkalosis

With the use of ¹⁴C-DMO (¹⁴C-5, 5-dimethyl-2,3-oxazolidinedione), a weak organic acid, we measured the intraerythrocytic hydrogen ion concentration in 16 acidotic and alkalotic patients. Whole blood pH, red cell 2,3-diphosphoglycerate, hemoglobin, oxyhemoglobin, plasma pCO₂, and plasma bicarbonate were measured simultaneously on heparinized arterial blood. The results show: (1) hydrogen ion concentration in the red cell varies directly with that of whole blood, (2) red cell concentration of 2,3-diphosphoglycerate varies inversely with the whole blood hydrogen ion concentration, and (3) red cell 2,3-diphosphoglycerate concentration also varies inversely with the intracellular hydrogen ion concentration. There were no significant relationships between the arterial total hemoglobin or oxyhemoglobin and intracellular or whole blood pH, nor was there any relationship between plasma pCO₂ or plasma bicarbonate and intracellular or whole blood pH. We concluded that in a number of clinical conditions in which the hydrogen ion concentration is altered, the cellular pH parallels that of the whole blood and that the 2,3-diphosphoglycerate concentration varies with the hydrogen ion concentration.