Mechanism of Action of Deferoxaminum on Iron Absorption

In confirmation of previous work oral administration of an iron‐chelating substance, deferoxaminum (DFO), was found to reduce absorption of inorganic but not haemoglobin iron. Retention of ionic iron was impaired whether the iron and DFO were mixed initially in a flask, in the stomach or in the small intestine. Oral DFO principally prevented the transfer of iron from gut lumen to plasma. Nevertheless, a small amount of iron was transferred to the plasma even in the face of a great excess of DFO. A portion of this absorbed iron was excreted in the urine together with DFO. Whether DFO combined with this absorbed iron before or after transfer to the plasma could not be determined. Intravenous DFO, however, was shown to chelate ionic iron in the presence of transferrin. Once iron was bound to transferrin, DFO could not remove it in vivo.