A Plasma Extract with Erythropoietic Activity

Abstract

Administration to intact rats of an extract, prepared from the plasma of phenylhydrazine-treated rabbits, results in significant increases in peripheral red cell counts, hemoglobin concentrations, reticulocyte percentages, hematocrit values, and in the concentrations of nucleated erythrocytes within the marrow. The extract exerts no significant influence upon the total and differential white cell numbers or the sedimentation rates and red cell fragility values. The factor may be related to, or identical with, the circulating “hemopoietine” hypothesized to be the humoral mediator of anoxia, the fundamental erythrocytogenic stimulus.