Transfer of lithium ions across the erythrocyte membrane

Mechanisms involved in the transfer of the lithium ion (Li⁺) across the erythrocyte (RBC) membrane were explored. Isolated erythrocytes were incubated in vitro at 37 ° under different experimental conditions, and either the uptake of Li⁺ into the cell or the efflux of the cation from the cell was measured. The presence of sodium ions in the incubation medium had a dual effect: (1) reducing the net accumulation of Li⁺ by erythrocytes, but (2) accelerating the rate of loss of Li⁺ from erythrocytes. Ouabain produced an increase in the net accumulation of Li⁺ by erythrocytes only if there was a rise in cell Na⁺. Furosemide did not affect the transfer of Li⁺ across the erythrocyte membrane, whereas phloretin did reduce net Li⁺ accumulation.