Membrane cholesterol depletion and K+ transport in high and low potassium sheep red cells

The effect of cholesterol depletion on potassium tracer fluxes was studied in sheep red cells. Removal by the plasma incubation method (5, 12, 30) of approximately 31 and 34% membrane cholesterol from high-potassium (HK) and low-potassium (LK) sheep red cells, respectively, did not induce significant changes in the steady-state cation composition of these cells nor in their passive (leak) and active (pump) K+ influxes. In cholesterol-depleted LK sheep red cells, there was no impairment nor augmentation of the Lp an antibody stimulated K+ pump flux and L1-antibody-mediated reduction of K+ leak flux indicating that the removed cholesterol does not contribute to the activity of the Lp and L1 antigens.