Mobilization of hematopoietic cells into peripheral blood in response to cyclophosphamide. Peripheral blood was obtained at the indicated times after a single intraperitoneal injection of 200 mg/kg of cyclophosphamide and analyzed for (A) absolute neutrophil count (ANC), (B) colony-forming cells (CFU-C), and (C) CD34⁺ lineage⁻ progenitors as described in Materials and Methods. Four to six age- and sex-matched mice were analyzed at each time point. Data represent the mean ± SEM.