Hepatic Ferritin Uptake and Hepatic Iron

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Abstract
The effect of hepatic iron on the uptake of ferritin was studied by perfusing livers from normal, iron deficient and iron–loaded rats with 125I–labeled ferritin. Unlabeled ferritin with tracer doses of labeled ferritin in concentrations of 0.02 to 2,700 nmol/L were studied. Rats were made iron deficient by feeding an established iron–deficient diet for 3 wk. Rats were iron loaded by injection of iron dextran (50 mg/wk) for 3 wk. The mean percentage of uptake of ferritin was similar for doses ranging from 0.22 to 22.2 nmol/Lof 125I–labeled ferritin. Uptake was minimal at 4°C. The mean Percentage uptake of ferritin was 78% ± 10% in the iron–deficient rats (mean hepatic iron = 1.5μmol/gm), 79% ± 10% in the normal animals (mean hepatic iron = 9.2 μmol/gm) and 78% ± 8% in the iron–loaded animals (mean hepatic iron = 192 μmol/gm). In this experimental system, modulation of hepatic iron did not affect uptake of ferritin, suggesting that regulation of the hepatic ferrition, suggesting that regulation of the hepatic ferritin receptor may not depend on hepatic iron content. The rapid uptakee of ferritin by the liver despite iron noregulation of non–transferrin–bound iron by hepatic iron and may play a role in the progressive iron overload seen in hemochromatosis.(HEPATOLOGY 1990; 11:805–808.)