Effect of cyclophosphamide on metabolic parameters of human platelets and polymorphonuclear leukocytes

The in vitro effect of cyclophosphamide on normal human platelets and polymorphonuclear leukocytes (PMN) was compared. Stimulated nitroblue tetrazolium test was found to be enhanced in PMN and decreased in platelets. RNA and protein synthetic capacities of platelets and PMN RNA synthesis were inhibited. Protein synthesis in PMN showed a non-significant tendency to decrease. Adenosine-3',5'-cyclic monophosphate levels were increased and glycogen content decreased in both types of cells. Glucose oxidation to CO₂ by resting PMN (both 1-¹⁴C glucose and 6-¹⁴C glucose) was inhibited, but enhanced in phagocytizing cells. In platelets, only 6-¹⁴C glucose oxidation by resting cells was increased by the drug. Oxidation of 1-¹⁴C glucose and 6-¹⁴C glucose by control PMN and platelets at rest and during phagocytosis was compared. It was found that only in PMN is phagocytosis accompanied by enhanced flux of glucose through the pentose monophosphate shunt and via glycolysis and the tricarboxylic acid cycle.