Factors controlling hemopoiesis: erythropoietic effects of "anemic" plasma.

Abstract

Abstract Normal rats given multiple intraperitoneal injections of the filtrate of phenylhydrazine-induced anemic rabbit plasma that had been boiled for one minute manifested a parallel increase in all peripheral erythroid values together with myeloid erythrocytic hyperplasia. The newly formed erythrocytes were normal in size. After boiling for 30 minutes, filtrates of the same anemic plasma induced erythrocytosis because of the production of microcytes, reticulocytosis, and increased marrow nucleated red cell counts without augmentation of the recipients' hemoglobin or hematocrit levels. Anemic plasma that had been processed by prolonged boiling evoked identical responses by parenteral and oral routes. When given by gastric tube, the anemic plasma that had been boiled for one minute did not enhance the recipients' circulating hemoglobin levels. Instead, these animals developed an erythromicrocytic response similar to that attributed to the thermostable plasma fraction. These data provide further support for the existence of two humoral erythropoietic factors. It is suggested that a relatively thermolabile factor, which is inactive orally, governs hemoglobin production by affecting the rate of erythrocytic differentiation from the primitive pluripotential marrow cells. The thermostable factor, which is active orally, apparently determines the number of mitoses which erythrocytic precursors undergo during maturation. Together, these two agents appear to regulate the size and hemoglobin content of each cell in addition to the amount of hemoglobin and number of erythrocytes formed.