[Change in energy metabolism of ascites cancer cells with a decrease in pH].

In Hank's balanced salt solution EL-4 ascites thymoma cells possessed endogenous respiration which was sufficient for the maintenance of their ATP level: pH decrease down to 6.0 had no effect either on endogenous respiration or the ATP level. Glucose had no influence on the respiration of EL-4 cells but inhibited that of Ehrlich ascites carcinoma (EAC) cells by 40% (Crabtree effect); respiration of the both cell lines was strongly (4-fold) inhibited after simultaneous addition of glucose, lactate and pH decrease. EL-4 cells had no endogenous glycolysis; EAC cells showed a low level of glycolysis only after pH decrease. Glucose addition led to activation of glycolysis (both inhibited 2-fold after a decrease of pH down to 6.0. The respiration inhibition at pH 7.3 and 6.0 caused no decrease of ATP depletion when glucose was present in the medium; this result may be due to suppression of ATP consumption. Incubation of EL-4 cells under respiration and glycolysis deficiency conditions resulted in a sharp ATP depletion; pH decrease delayed this depletion.