Effects of Inhibitors of Glycolysis on Intracellular pH and on Accumulation of Glycolytic Intermediates in the Ehrlich Ascites Tumor Cell

Ehrlich ascites tumor cells were incubated aerobically in a Krebs-Ringer phosphate buffer. The glycolytic intermediates, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, dihydroxyacetone phosphate, glyceraldehyde phosphate, and glycerol-1 -phosphate, were measured, and intracellular pH was calculated from the distribution between intracellular and extracellular water of the weak acid, 5,5-dimethyl-2,4-oxazolidinedione. When glucose was added to cells incubated with 0.2 mM iodoacetate, lactate production was completely blocked. Incubation with 40 mM oxamate partially inhibited lactate production. Both these inhibitors caused the accumulation of phosphorylated intermediates, principally dihydroxyacetone phosphate. Intracellular pH fell almost to as great an extent when glucose was added in the presence of these inhibitors as when it was added in their absence. When 2-deoxy-D-arabino-hexose (2-deoxyglucose) was added to the cells, there were accumulation of 2-deoxyglucose-6-phosphate and a fall of intracellular pH. When 2-deoxyglucose was added after incubation with glucosone, there were no phosphorylation of 2-deoxyglucose and no fall of intracellular pH. It is concluded that the accumulation of phosphorylated intermediates accounts for intracellular acidification when lactate production is inhibited.