[Hematopoietic stem cell count in mice with stimulated and suppressed erythropoiesis. I. Blood loss and acute hypoxia].

Polypotential hemopoietic stem cell numbers were determined by means of the splenic colony-forming unit (CFU-S) method in bone marrow and spleen of CBA mice in different periods after bleeding and acute hypoxia. After these treatments, radioactive isotope (59Fe) uptake by erythroid cells, considered as an index of erythropoietic activity, enhanced in the spleen, but in the bone marrow it either diminished (after acute hypoxia), or remained unchanged (after bleeding). Bleeding caused a considerable increase in the splenic CFU-S numbers, but the bone marrow CFU-S contents were unchanged. It was found that splenic CFU-S number decreased on the 1st and 4th days after acute hypoxia, but increased on the 7th day; bone marrow CFU-s numbers increased on the 7th day. Possible mechanisms involved in the hemopoietic stem cell perturbation in the hemopoietic organs after the erythropoiesis stimulating treatment are discussed.