The influence in vivo of murine colony-stimulating factor-1 on myeloid progenitor cells in mice recovering from sublethal dosages of cyclophosphamide.
Pure murine colony-stimulating factor-1 (CSF-1) was assessed for its effects in vivo in mice pretreated seven days earlier with a sublethal dosage of cyclophosphamide. The multipotential (CFU-GEMM), erythroid (BFU-E), and granulocyte-macrophage (CFU-GM) progenitor cells in these mice were in a slowly cycling or noncycling state. Intravenous administration of 20,000 units of CSF-1 to these mice stimulated the hematopoietic progenitors into a rapidly cycling state in the marrow and spleen within three hours. Significant increases in absolute numbers of marrow and spleen CFU-GM and spleen BFU-E and CFU-GEMM were also detected. No endotoxin was detected in the CSF-1 preparation by Limulus lysate assay, and treatment of CSF-1 at 100 degrees C for 20 to 30 minutes completely inactivated the in vitro and in vivo stimulating effects. The effects of CSF-1 were not mimicked by the in vivo administration of 0.1 to 10 ng Escherichia coli lipopolysaccharide. These results suggest that the effects of CSF-1 in vivo were not due to contaminating endotoxin or to a nonspecific protein effect. CSF-1 did not enhance colony formation by BFU-E or stimulate colony formation by CFU-GEMM in vitro, thus suggesting that at least some of the effects of CSF-1 noted in vivo are probably indirect and mediated by accessory cells.
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D001854:Bone Marrow Cells; D002455:Cell Division / Q000187:drug effects; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000494:pharmacology*; D003520:Cyclophosphamide / Q000633:toxicity*; D004926:Escherichia coli; D006410:Hematopoiesis / Q000187:drug effects; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D013154:Spleen / Q000166:cytology / Q000187:drug effects
D003115:Colony-Stimulating Factors; D008070:Lipopolysaccharides; D003520:Cyclophosphamide