ROLE OF TRANSFERRIN IN DETERMINING INTERNAL IRON DISTRIBUTION

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 49  (6) , 957-966
Abstract
The behavior in vivo of transferrin in loading and unloading Fe from its 2 sites was examined in rats. Radio Fe entering the plasma from the gastrointestinal tract in Fe-deficient, normal and Fe-loaded rats did not differ in its subsequent tissue distribution between erythroid marrow and liver of normal recipients from a 2nd isotope added to the same plasma in vitro. Loading studies in vitro were then carried out employing a reticulocyte incubation model designed to place 1 isotope predominantly on 1 site of transferrin, more available to the erythron, and the 2nd isotope on the other site, more available to the liver. In 15 groups of animals in which 3 different Fe salts were employed to load transferrin with Fe, the mean isotope ratio in the erythron was 1.03 (.+-.0.06 SD) and the mean liver ratio was 0.75 (.+-.0.21 SD). Incubation of plasma with reticulocytes resulted in contamination of the plasma by radioactive Hb. After allowance was made for hepatic uptake of radio Hb in the 13 groups in which proper correction could be made, the isotope ratio in the liver became 0.97 (.+-.0.17 SD). Fe atoms from the 2 sites of transferrin apparently have similar tissue distributions in vivo in the experimental situations examined.