The effects of some drugs which induce agranulocytosis on the metabolism of separated human polymorphonuclear leucocytes and lymphocytes.

1. Lymphocytes and polymorphonuclear leucocytes were separated from normal human blood by the method of Rabinowitz (1964).2. The oxygen uptake, lactic acid production and glucose uptake of suspensions of these cells in vitro were measured. The values obtained agree with published data using comparable techniques.3. Amidopyrine, chloramphenicol, chlorpromazine, phenylbutazone and thiouracil, in high concentrations, depressed the oxygen uptake of polymorphs, but not that of lymphocytes. With amidopyrine, chlorpromazine and thiouracil significant inhibition was produced by concentrations equal to therapeutic plasma levels. High concentrations of the drugs, except chlorpromazine, stimulated the glucose uptake of lymphocytes but not that of polymorphs. Tetracycline and sulphisoxazole were without effect on either parameter of leucocyte metabolism.4. Because of erythrocyte contamination the lactic acid production of lymphocytes could not be determined. Lactate production by polymorphs was not affected by any of the drugs studied.5. The significance of these results is discussed. It is suggested that there is a relationship between ability to induce agranulocytosis and effect on leucocyte metabolism in vitro.