Human lymphocyte potassium content during the initiation of phytohemagglutinin-induced mitogenesis

The K+ content of human lymphocytes has been examined during the initial 24 hours after exposure of cells to phytohemagglutinin (PHA). We have reconfirmed that lymphocyte K+ exchanges rapidly for extracellular counterions during preparative washing if cells are exposed to PHA. By using a technique to measure cation content which does not require removal of cells from their culture medium, we have shown that K+ does not change for 24 hours following PHA treatment. Previous reports have demonstrated that an enhanced uptake of K+ occurs in lymphocytes treated with PHA. This increased uptake may be a compensatory change for an increased exodus, explaining the failure of K+ to change following lectin treatment.