Studies on Erythropoiesis IX. Mechanism of Decreased Erythropoiesis In Experimental Polycythemia

Abstract

1) Reduction of erythropoiesis in rats rendered polycythemic by intraperitoneal infusion of packed red cells bears a relation to the degree of plethora produced. Plasma from anemic rats, a heat-denatured plasma extract from a patient with aplastic anemia, and subcutaneous cobaltous chloride all stimulate erythropoiesis in the polycythemic rat. These observations are consistent with the theory that decreased erythropoiesis in the polycythemic rat is the immediate consequence of a decreased titer of erythropoietin in these animals, and constitute further support for the theory of the humoral regulation of erythropoiesis. 2) In these experiments it was not possible to suppress erythropoiesis completely, as measured by the reticulocyte count, in normal rat by transfusion, although complete suppression was readily accomplished in transfused hypophysectomized rat.