Role of humoral factors in the regulation of hemopoiesis during immobilization stress.

Experiments were performed on CBA/CaLac mice with hyperplasia of hemopoiesis induced by 10-h immobilization. Erythropoietic and colony-stimulating activity increased under the influence of hemopoietic growth factors and other humoral substances, which plays a major role in the increase in bone marrow cellularity during immobilization stress. Erythropoietin stimulated proliferation of erythroid colony-forming units, while granulocyte colony-stimulating factor accelerated maturation of granulocyte precursors.