Effects of calcium and verapamil on normal and tumor murine leukocytes.

Although no differences in membrane stabilization by calcium were noted between leukemic (P-388) and normal murine leukocytes, tumor cells were shown to be more resistant to damage by ethanol but not by desmethylchlorpromazine. Furthermore, verapamil protected tumor cells but not normal cells against the disruptive effect of desmethylchlorpromazine but not that of ethanol. The protective action of verapamil was evident even in the absence of calcium. Thus leukemic cells appear to be altered so that the effects of certain membrane active agents are changed but the membrane stabilizing function of calcium is normal.