The Proliferative States of Mouse Granulopoietic Progenitor Cells 1

Abstract

Summary

Mouse granulopoietic progenitor cells can be detected by their capacity to form colonies in culture (CFU-C). The proliferative state of these cells was studied by determining the degree to which their colony-forming capacity was destroyed following exposure to a pulse of high specific-activity ³HTdR. When marrow was obtained from normal adult mice 35% of CFU-C were inactivated by this procedure. In contrast, 80% of CFU-C were inactivated when cell populations were obtained from regenerating bone marrow. These results are interpreted to mean that CFU-C in normal mice are partitioned into two populations, one proliferating rapidly and the other slowly or not at all. In regenerating marrow the partition is changed, with all or almost all of the cells proliferating rapidly.