Polycythemic mice--an appropriate model for investigation of granulopoiesis.

In posthypoxic polycythemic mice (P) expanded granulopoiesis was found. After aplasia induced by a sublethal dose of cyclophosphamide (Cy), more granulocytic cells both in the bone marrow and spleen were found in P than in normal (N) mice treated in the same way. Spontaneous regeneration of granulocytic precursors during the first three days after Cy was more intensive in P mice, and a significant role of the spleen in CFU-GM regeneration was observed. It is suggested that P animals could be used as an appropriate model for investigation of the cell specificity of humoral regulators of granulopoiesis and their action, as well as in studies on the competition of granulocytic and erythroid cells.