Comparison of Erythropoietin Response in Mice Following Polycythemia Induced by Transfusion or Hypoxia

Experiments were undertaken to measure the response to erythropoietin in mice during the first two weeks after the induction of polycythemia. A comparison of the size of the response obtained utilizing two different means of producing polycythemia was made. It was found that a 50 per cent higher level of iron incorporation was obtained if hypoxia was used rather than transfusion. It is suggested that this difference may be due to an alteration in both the compartment size and the cell cycle time of the erythropoietic stem cell in mice exposed to prolonged hypoxia.