Characterization of Dextran Sulfate-treated Ascites Tumor Cells and Their Repair by Ascites Fluid

Exposure of Ehrlich ascites tumor cells to the polyanion dextran sulfate altered the permeability of the plasma membrane resulting in decreased glycolysis and respiration, enhanced permeability to Rb+ and adenosine 5'-triphosphate, and increased staining by erythrosin B. The inhibition of respiration was reversed by the addition of inorganic phosphate, whereas restoration of glycolysis required both inorganic phosphate and adenosine 5'-monophosphate. The membrane lesion was repaired by injection of dextran sulfate-treated cells into mice or by in vitro exposure to a heat-stable extract from ascites fluid. Reparied cells were no longer stained by erythrosin B and glycolyzed without added adenosine 5'-monophosphate. The time course of repaire was separable into a rapid initial repair of the membrane lesion followed by a slower recovery of the normal intracellular ionic composition. Both phases were insensitive to inhibitors of protein synthesis. The repair activity of ascites fluid was heat stable and was composed of both dialyzable and nondialyzable factors. Incubation of dextran sulfate-treated cells with ascites fluid restored Rb+ uptake and abolished the adenosine 5'-triphosphate-stimulated Ca2+ uptake.