Effects of a single injection of PEG-rHuMGDF on the recovery of various hematopoietic progenitor cells after irradiation in mice. Mice were intravenously given 80 μg/kg PEG-rHuMGDF 1 (•), 24 (▴), or 48 (▪) hours after irradiation, or vehicle (○) 1 hour after irradiation. The number of CFU-MK, BFU-E, CFU-GM, and day 12 CFU-S in femoral bone marrow before irradiation and at indicated times after irradiation was examined using the respective adequate progenitor assays. The number of CFU-MK, BFU-E, CFU-GM, and day 12 CFU-S per femur in untreated normal mice was 2,340 ± 314, 1,030 ± 474, 9,900 ± 1,772, and 2,436 ± 407, respectively. *P < .05, **P< .01: significantly greater than vehicle-treated, time-matched controls.