Differential kinetic responses of the erythroid and myeloid compartments of murine marrow to irradiation

The radiation response of the erythroid and myeloid compartments of murine bone marrow was studied over a 10 day interval following 450R TBI. Both early (BFU/sub e/) and late (CFU/sub e/) progenitors of erythropoiesis as well as the erythropoietic repopulating potential (ERA) were monitored in addition to the pluripotential CFU/sub s/, myeloid (CFU/sub c/) progenitor and granulopoietic repopulating potential (GRA). The kinetics of insult recognition and recovery demonstrated marked differences between the magnitude and duration of response in the erythroid and myeloid compartments. Myeloid suppression was an order of magnitude more severe than that observed for the erythroid compartment (22 fold reduction in BFU/sub e/ vs. 400 fold reduction in CFU/sub c/) with corresponding recovery intervals suggesting that myelopoiesis is far more sensitive to radiation than erythropoiesis. Assessment of the CFU/sub s/ compartment 10 days post 450R suggests that the response of the ''pluripotential'' stem cell compartment is similar to myelopoiesis. The data are discussed in terms of the repopulating potential of both the erythroid and myeloid compartments