Effect of Adrenomimetics and Serotonin on Polypotent Stromal and Hemopoietic Precursors in Cytostatic Myelosuppression

Effects of serotonin and adrenomimetics (phenylephrine and isoprenaline) on bone marrow stromal and polypotent hemopoietic precursors were studied in vitro on the model of cyclophosphamide- induced myelosuppression. It was found that under conditions of myelosuppression, adrenomimetics potentiate differentiation of polypotent hemopoietic precursors into mature precursors (granulocyte-macrophage and granulocyte CFU) initiated by granulocytic CSF, while serotonin suppresses these processes. Adrenomimetics (especially, isoprenaline) abolish high rate of division of stromal precursors and suppress the growth of granulocytic CSF induced by fibroblast-like cells. Serotonin does not affect proliferation of stromal precursors, but potentiates the granulocytopoiesis-stimulating effects of fibroblasts.