Effect of iron saturation of transferrin on hepatic iron uptake: an in vitro study.

Studies were performed to delineate the effect of percentage of saturation of transferrin and total iron concentration on the rate of uptake of iron by the perfused rat liver. Normal and iron-deficient rat livers were perfused with sera that contained varying concentrations of 59Fe-labeled iron and transferrin saturation. Varying the percentage of saturation of transferrin while maintaining a constant concentration of iron did not influence the hepatic uptake of iron. However, raising the concentration of iron in the perfusate while maintaining a constant saturation of transferrin did increase the uptake of iron by the liver. At similar concentrations of iron and transferrin saturation, iron-deficient livers took up greater amounts of iron than did normal livers. In our experiments, the hepatic uptake of transferrin-bound iron is determined by (1) the concentration of iron in perfusate and (2) the status of iron stores in the liver being perfused.