The Monovalent Cation Content and Adenosine Triphosphatase Activity of Human Normal and Leukemic Granulocytes and Lymphocytes: Relationship to Cell Volume and Morphologic Age

Differences in volume, water content and weight of leukocytes of different morphologic type are described. These differences make it mandatory that the influence of those factors which contribute to the denominator in comparative studies of leukocyte characteristics be considered if different cell types are being compared. The influence of cell isolation on monovalent cation content is emphasized. Restoration of a high potassium, low sodium steady-state occurred at 37 C. after incubation in physiologic solutions. Inhibition of this cation restoration by ouabain, or deviations from optimal extracellular pH, optimal ambient temperature and optimal extracellular potassium concentration coupled with the presence of ouabain inhibitable monovalent cation activated adenosine triphosphate hydrolysis in vitro support the presence of active cation transport in all types of human leukocytes studied. It is likely that discrepant values for leukocyte cation content and absence of monovalent cation activated ATPase previously reported are related to technical factors.

Leukemic and normal granulocytes and lymphocytes of similar morphologic type do not differ in their monovalent cation content or in sodium-potassium ATPase activity. Cell volume of leukemic and normal small lymphocytes and PMNG’s parallels their cation content. Immature granulocytes and small lymphocytes have higher sodium-potassium ATPase activities than mature granulocytes. Sodium concentration and water content were also slightly higher in immature granulocytes and lymphocytes as compared to PMNG’s. The data are consistent with the hypothesis that increased sodium-potassium ATPase activity is a biochemical feature of leukocytes with the potential to divide and differentiate. The impaired mitotic capacity of human leukemic blast cells does not appear to be related to a deficiency in sodium-potassium ATPase activity or a resultant alteration in intracellular monovalent cation content.