Effect of erythrocyte breakdown products on stem cells and erythropoietin formation

In experiments on CBA mice and albino rats the effect of erythrocyte breakdown products (EBP) on the number of colony-forming units (CFU), differentiation of stem cells, and erythropoietin production was studied. After three or four injections of EBP to normal or lethally irradiated (1000 rad) mice, no changes in the number of CFU or in differentiation of the stem cells were observed after transplantation of bone marrow. Daily administration of EBP to mice for 3 days before irradiation (1000 rad) and bone marrow transplantation led to an increase in the number of colonies in the recipients' spleen, mainly on account of colonies of erythroid type. Injection of EBP into the animals did not change the erythropoietic activity of the blood serum. The possible role of EBP in the mechanism of autoregulation of erythropoiesis is discussed.