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Uptake of transferrin‐bound and nontransferrin‐bound iron by reticulocytes from the belgrade laboratory rat: Comparison with wistar rat transferrin and reticulocytes
Author(s) -
Farcich Elizabeth A.,
Morgan Evan H.
Publication year - 1992
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.2830390104
Subject(s) - transferrin , transferrin receptor , chemistry , cytosol , biochemistry , reticulocyte , sucrose , microbiology and biotechnology , biology , messenger rna , gene , enzyme
The mechanism underlying the impaired uptake of iron from transferrin by reticulocytes from the Belgrade laboratory rat was investigated using 125 I‐ and 59 Fe‐labeled transferrin isolated from homozygous Belgrade rats and from Wistar rats, nontransferrin‐bound Fe(II) in an isotonic sucrose solution, and reticulocytes from Belgrade and Wistar rats. The Belgrade rat transferrin had the same molecular weight and net charge as Wistar rat transferrin, donated iron equally well to both types of reticulocytes, and competed equally for transferrin binding sites on the cells. Hence, the defect in iron uptake by Belgrade rat reticulocytes could not be attributed to an abnormality of the transferrin molecule. The rate of uptake of Fe(II) from sucrose into the cytosolic and stromal fractions of Belgrade rat reticulocytes was only about 35% as great as that by Wistar rat reticulocytes. With both types of cells, the uptake process was saturable, suggesting the presence of a carriermediated process. It was therefore concluded that the defect in iron uptake by Belgrade rat erythroid cells is probably the consequence of a deficiency in a membrane carrier for iron.