Storage iron exchange in the rat as affected by deferoxamine

The initial tissue localization and redistribution of radioactive iron injected intravenously into the rat as ferritin, chondroitin sulfate, and nonviable red cells was determined. Ferritin iron, initially localized in the hepatocyte, showed minimal redistribution over 24 hours in the normal animal. This may be compared with the active release of iron from the reticuloendothelial cell after the intravenous injection of nonviable red cells and chondroitin sulfate iron. All forms of iron were actively mobilized in iron-deficient animals. The effect of chelation of iron by deferoxamine (DFO) on the redistribution pattern over 4 to 6 hours was determined in iron-deficient, normal, iron-loaded, and phenylhydrazine-treated rats to evaluate the effect of iron stores and erythropoiesis. Use of DFO resulted in extensive chelation of radioactive iron within the hepatocyte and greatly reduced the amount of hepatocyte iron available for erythropoiesis. Very little chelation of reticuloendothelial cell-processed iron occurred, and there was little decrease in its utilization for red cell production. Total urinary chelate iron was independent of erythropoiesis but varied in parallel with the iron load of the animal. These studies suggest that DFO does not act on the reticuloendothelial cell but does have at least two sites of action, both of which relate to total storage iron. One involves hepatocyte stores with excretion into the intestinal tract. The other, possibly located at the hepatocyte membrane, results in urinary iron excretion.