Intravascular granulocyte kinetics in developing calves
Carlson, G.P.; Kaneko, J.J.
American Journal of Veterinary Research 36(4 Part 1): 421-425
1975
ISSN/ISBN: 0002-9645 PMID: 1124877 Document Number: 92284
Intravascular granulocyte kinetic values of normal developing calves were determined, using chromium radioisotope as the cell label. A total of 15 kinetic trials were conducted in the calves at 8 to 365 days of age. Clearance of labelled granulocytes from the circulation was an exponential function. Kinetic findings from the oldest group of calves (7 experiments on 5 calves, 180 days of age and older) were remarkably similar to those reported for man. Mean total blood granulocyte pool was 6.34X108 granulocytes/kg of body weight, of which 45.6% was in the circulating granulocyte pool. Mean clearance half-life (T1/2) was 8.9 hours, and mean daily granulocyte turnover rate was 12.44X108 granulocytes/kg of body weight. In the oldest calves there was significant correlation between the blood granulocyte count and the total blood granulocyte pool size. There was also significant correlation between the total blood granulocyte pool size and the clearance half-life. The youngest calves (4 experiments on 4 calves, 8 to 16 days of age) had much larger total blood granulocyte pool and shorter intravascular half-life than did the oldest calves. These factors combined to yield a greater daily granulocyte turnover rate of 39.91X108 granulocytes/kg in the youngest calves. Calves of an intermediate age group (70 to 127 days) had intermediate kinetic values.