Calcium induced potassium efflux in erythrocytes of marine teleosts

The effect of the calcium-ionophore A23187+ Ca++ on the K+ transport in the intact erythrocytes of sea-water fishes was investigated. A23187+ Ca++ induced a significant increase in the cell-membrane permeability for potassium ion, while A23187+ Mg++ was ineffective. Addition of EGTA to the medium blocked the ionophore+ Ca++ effect. Quinidine inhibited the A23187+ Ca++-induced K+ transport in the nucleated fish red cell. Propranolol is effective in the fish RBC in presence of Ca++ and EGTA. The relationship of the calcium-induced alkali cation transport in nucleated red cell to that in human red cell is discussed.