LEUKOKINETIC STUDIES. III. THE DISTRIBUTION OF GRANULOCYTES IN THE BLOOD OF NORMAL SUBJECTS*

Abstract

When granulocytes were labeled in vitro with radioactive diisopropylfluorophosphate (DFP32) and returned to the circulation of the donor, only 50% of the labeled granulocytes was present in the circulation at completion of the infusion. The following experiments were designed to test the hypothesis that the initial rapid egress of 50% of the cells represents distribution of labeled granulocytes in a larger pool than that calculated from the blood volume and granulocyte count. When epinephrine was infused with the labeled granulocytes or when subjects were exercised immediately after the infusion, a granulocytosis occurred and 78.8% and 79% of the infused cells respectively could be accounted for in the circulation. Neither epinephrine nor exercise increased the size of the total distribution compartment (TBGP), but both stimuli caused an increase in the size of the circulating granulocyte pool (CGP). When granulocytes were mobilized into the circulation 3 hours after infusion, there was no change in specific activity of the cells in the circulation. Granulocytes damaged by storage could not be prevented from leaving the circulation by administration of epinephrine. These studies are interpreted as indicating that infused granulocytes are distributed in a TBGP made up of two compartments, the CGP and the marginal granulocyte pool (MGP), which are in rapid equilibrium with each other. The size of these pools as measured in 45 normal males is: TBGP, 65.3 [plus or minus] 22.7; CGP, 30.7 [plus or minus] 11.8; and MGP, 34.6 [plus or minus] 15.6.