Neutrophil kinetics in the dog

Abstract

The production of neutrophils in dogs has been estimated from the number of postmitotic neutrophils in the marrow and the transit time of a [3H]thymidine pulse. The number of postmitotic neutrophils was derived from the erythron iron turnover measurement of erythroid number and the neutrophil erythroid ratio in bone marrow sections. The mean value for marrow postmitotic neutrophils in dogs was 5.61 ± 0.56 x 109 cells/kg. The mean transit time of these neutrophils was calculated to be 82.1 hr. A marrow production of 1.65 x 109 neutrophils/kg/day was calculated from these data. The turnover of circulating neutrophils was measured by [3H]thymidine and [32P]diiosopropylphosphofluoridate (DF32P) labeling of blood neutrophils. [3H]Thymidine labeling gave a calculated recovery of 65%, a t1/2 disappearance time of 6.7 hr, and a calculated turnover of 1.66 x 109 cells/kg/day. Corresponding results with DF32P tagging were 51%, 5.4 hr, and 2.89 x 109 cells/kg/day. The discrepancy between these 2 tags persisted in doubly tagged cells and was considered to be due to elution of DF32P.