Leukokinetic studies. IV. The total blood, circulating and marginal granulocyte pools and the granulocyte turnover rate in normal subjects.

When granulocytes are labeled with diisopropyl-fluorophosphate (DFP32) and then returned to the circulation of the donor, the labeled granulocytes are distributed in a pool of cells which is approximately two times larger than that calculated from the blood volume and the concentration of granu-locytes in the circulating venous blood (1, 2). This pool has been referred to as the total blood granulocyte pool (TBGP) and it consists of two subcompartments or pools. These pools have been designated the circulating granulocyte pool (CGP) and the marginal granulocyte pool (MGP). The size of the CGP can be calculated from the blood volume and the absolute granulocyte count. Equilibration between the granulocytes in the CGP and in the "noncirculating" or MGP is sufficiently rapid and complete to allow these two pools to be considered as one kinetically, and the size of the TBGP can be determined by the isotope dilution principle. Since the cells are removed from the TBGP in an exponential fashion with a mean half-time disappearance (Ti) of 6.6 hours, the granulocyte turnover rate (GTR), that is, the number of granulocytes turned over through the blood in a unit of time, can be calculated. The purpose of this paper is to present data on the GTR in normal subjects, as well as additional data on the size of the TBGP, CGP and MGP in normal subjects. The influence of steroids, physical exercise, epinephrine and bacterial endotoxin on these parameters in normal subjects has also been studied. Twenty-five volunteers from the Utah State Prison, in addition to the 45 subjects previously reported (1, 2), were used in these studies. All of the subjects were normal healthy males, 20 to 50 years of age, with normal leukocyte values. The subjects ate breakfast at 6:00 a.m. and the infusion of labeled blood was begun between 8:00 and 10:00 a.m. The methods for labeling blood in vitro, for the isolation of leukocytes from the blood samples, for the determination of leukocyte radioactivity, and for the calculation of the TBGP, CGP and T± have been described in previous publications (1, 2, 5). The GTR, defined as the number of granulocytes turned over through the blood each day per kilogram body weight, was calculated from the following equation (6): GTR = 24 X 0.693/Ti (hrs) X TBGP (no. cells X 107/kg). The DFP32 was purchased from the New England Nuclear Corp., Boston, Mass., as a dilute solution …