The effects of ionophore A23187 on erythrocytes. Relationship of atp and 2,3-diphosphoglycerate to calcium-binding capacity.

The divalent cation ionophore, A23187, was employed as a means to load fresh human erythrocytes with calcium, and the capacity for accumulation was characterized. Erythrocytes exposed to A23187 in calcium-containing media rapidly accumulated calcium in millimolar quantities. The final cellular concentration was dependent upon medium calcium concentration and the size of the cellular organophosphate pool. When ATP and 2,3-diphosphoglycerate contents were depleted or repleted, the cellular calcium content changed proportionally. Calcium loading of fresh erythrocytes produced no discernible change in the cellular concentrations of ATP or 2,3-diphosphoglycerate. Calcium accumulation was also accompanied by loss of cellular potassium and H2O, deterioration of cell filterability, and spheroechinocytic transformation.