[Effect of colony-stimulating activity on hematopoiesis in the organ culture of mouse embryonal liver].

The effect of the colony-stimulating activity (CSA) on hemopoiesis in a long-term culture (4.5 week) of mouse embryonal liver was studied. After addition of the spleen cell-conditioned medium containing CSA to the organ culture, there was a decrease in the number of CFUs and in the granulocyte and macrophage precursors. However, the production of granulocytes and macrophages in the test cultures either did not fall or increased with primary differentiation of neutrophils. Addition of the medium with CSA shifted the equilibrium in the culture towards more intense production of differentiated cells at a lower level of the maintenance of precursors.