Studies on modification on the cellular response to injury.

Extracellular acidosis (pH 6.6) has been found to delay the lethal effect of p-chloromercuribenzene sulfonic acid on Ehrlich ascites tumor cells. At pH 6.6, 50 per cent of the cells died within approximately 80 minutes, compared with approximately 10 minutes at pH 7.5 or approximately 5 minutes at pH 8.0. It was also observed that low pH produced a dissociation between potassium loss, ATP levels, cell volume, and cell death. The possible mechanism of this effect is discussed; it is our hypothesis that it involves proton interactions with plasma membrane components which either affect available membrane sulfhydryl groups or otherwise stabilize the cell membrane against loss of semipermeable characteristics and cellular lysis.