Comparison of cytosolic products formed in rat liver in response to parenteral and dietary iron loading

Two different methods were used to create a situation of iron (Fe) overload in rats. One group of rats received Fe dextran, and another group of rats received a carbonyl Fe-enriched diet. The ferritins present in the liver cytosol of these rats were isolated and compared. From each group, two cytosolic products were isolated with the use of ultracentrifugation: a cytosolic ferritin fraction (CF) and a (slower sedimenting) light ferritin fraction (CLF). There were no differences with respect to the protein coat (subunit composition and amino acid analysis). Analysis of the Fe core revealed that the two CF fractions were similar, whereas the two CLF fractions differed with respect to their Fe content and to the packing of their cores. The carbonyl CLF product contained less Fe atoms/molecule, which, moreover, seemed to be packed in a less compact way.