title: Production of presumptive humoral haematopoietic regulators in canine cyclic haematopoiesis.
abstract: Conditioned media (CM) were prepared according to previously published techniques from the bone marrow of dogs with cyclic haematopoiesis (CH). CM prepared from day 9 marrows inhibited mouse bone marrow CFU-s proliferation rate while CM from day 10 marrows were stimulatory and also contained an erythroid stimulating factor which appeared to be erythropoietin. In addition a highly significant trend from CM containing CFU-s inhibitory materials to media with CFU-s stimulatory activity was observed through cycles day 1 to 8. These studies further support the concept that CH is due to a defect in factors controlling stem cell proliferation and suggest that a major event occurs in CH dog marrow on days 9 and/or 10 of the cycle.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000378:metabolism*; D001855:Bone Marrow Diseases / Q000662:veterinary*; D003114:Colony-Forming Units Assay; D003470:Culture Media; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D004921:Erythropoietin / Q000032:analysis; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D051379:Mice; D013997:Time Factors
chemical_list: D003470:Culture Media; D004921:Erythropoietin