Intra- and extracellular calcium in Ehrlich ascites tumor cell.

Calcium concentration in intra- and extracellular fluid from Ehrlich ascites tumor cells has been studied. The higher content of calcium in the outer cell fluid appears as a possible factor determining the behavior of the cell membrane. While in the cytoplasm macromolecular compounds such as lipo- and nucleoproteins seem to play an important role in calcium-binding, in the extracellular fluid calcium is likely to be bound to small molecules (presumably short chain polyphosphates). The significance of calcium-binding changes at the cell membrane level in the carcinogenesis and in the physiological behavior of the tumor cells is discussed.