The activation of Na+ transport is due to the exchange of
protons formed via
glucose conversion into
lactate for Na+, i.e., to the stimulation of the Na+/H+-antiport. Experimental results and theoretical calculations suggest that in
glucose-containing medium the Na+ transport increases from 0.75 to 1.78 pmol/hour per cell. The permeability of plasma membranes for K+ increases 2.75 fold, while the passive flux of Na+ diminishes. The intensity of O2 adsorption by
ascites tumor cells does not practically depend on the
monovalent cation concentration gradient between the cells and the culture medium, whereas the rate of glycolysis decreases simultaneously with the diminution of the concentration gradient. In synchronized cultures at the beginning of the mitotic cycle, the bulk of
ATP resynthesized via glycolysis is utilized for the synthesis of
biopolymers, whereas that at the end of the S-phase and in the G2-phase is utilized for
cation transport across plasma membranes. From 35 to 100% of the whole amount of
ATP resynthesized via glycolysis is utilized for transport purposes. It is concluded that the observed increase in the Na+/K+ ratio in
ascites tumor cells is connected with their enhanced ability to synthesize
lactic acid. Presumably, glycolysis is one of the regulatory mechanisms of intracellular ratios of
monovalent cations.