Evidence for a Physiologic Role of Erythropoietin in Fetal Erythropoiesis

Abstract

Abstract Administration of antibody prepared in rabbits against human urinary Ep to fetal sheep during the last third of the gestation period resulted in a suppression of erythropoiesis in the fetus. This was evidenced by a sharp decrease in the numbers of circulating reticulocytes and a reduced rate of 59Fe incorporation into RBC, spleen, and bone marrow, effects ascribable to a neutralization of endogenous Ep. In addition, there was a significant decrease in the numbers of nucleated erythroid cells in the bone marrows of these fetuses. These results point to a physiologic role for Ep in fetal erythropoiesis.