Abstract
In the present study we have compared some molecular characteristics of factors stimulating erythropoiesis found in the serum from patients with (a) aplastic anemia and (b) with erythremia due to anoxia, and in cyst fluid from patients with erythremia secondary to (c) a renal cyst and (d) a cerebellar hemangioblastoma. The biological activity of each of the four materials was found to migrate as an α2-globulin on zonal electrophoresis and was destroyed by treatment with sialidase and trypsin; this implies that these materials are mucoproteins with similar electrophoretic mobility. The erythropoietin activity was also completely neutralized by an antiserum made in rabbits to an extract of urine of anemic patients. This implies that these materials share common antigenic determinants. Thus, the erythropoiesisstimulating factors in human anemic and anoxic serum, cerebellar hemangioblastoma cyst fluid, and renal cyst fluid appear to be similar, if not identical. Therefore, the pathogenesis of the erythrocytosis seen in association with renal cysts and cerebellar hemangioblastomas appears to be due to the secretion of erythropoietin by these lesions.
