Cation Movements in the High Sodium Erythrocyte of the Cat

The uptake of (42)K and (24)Na by cat erythrocytes was investigated. Under steady-state conditions, the nontransient component of (42)K influx was found to be 0.18 ± 0.01 meq/liter RBC/hr and insensitive to ouabain (100 µM); the corresponding value for (24)Na was 17 ± meq/liter RBC/hr. A study was made of the effects of anions upon cation movements in these and other mammalian red cells. Iodide was found to inhibit markedly (>50%) Na inward movements in cat and dog but not in the other erythrocytes. An increase (15–30%) in K uptake in the presence of iodide was noted in all the mammalian cells studied.