Kinetics of erythropoiesis. A comparison of response to anemia induced by phenylhydrazine and by blood loss

¹ Department of Medicine, School of Medicine, University of Washington, Seattle, Washington

Quantitative measurements of the erythron were made in rabbits. Anemia was produced by red cell removal (group I), hemolysis from phenylhydrazine (group II) and red cell removal with replacement by nonviable erythrocytes (group III). Young red cells, including nucleated and reticulated cell forms, totaled 1.67 x 10¹⁰ cells in the normal animal. In anemic animals, by the 3rd day this had increased to 3.59 x 10¹⁰ (group I) and 3.68 (group II). By the 6th day, average values were 7.24 (group I) and 7.1 (group II). There was a greater proportion of young cells in the nucleated form in group I as compared with group II. The addition of nonviable cells (group III) did not augment erythropoiesis in bled animals. A reticulocyte shift from marrow to circulating blood, proportionate to the degree of anemia, was observed. These studies indicate an augmentation of the rate of erythropoiesis to about three times normal. There was no evidence that products of red cell destruction influence the rate of erythropoiesis.