The Rate of Removal of Radioactive Iron From the Plasma—an Index of Erythropoiesis 1

Transport iron normally exists in the plasma as ferric beta-l-globulinate. Since in most individuals the greater part of the body iron is incorporated in the hemoglobin of the red blood cells, it is probable that changes in the production and destruction of these erythrocytes will be reflected in the turnover of plasma iron. Radioactive iron of high specific activity is particularly useful for a study of iron metabolism since it can be injected intravenously in tracer amounts without changing the steady state of the organism; the turnover of this radioiron will then mirror the metabolism of the iron in the body.