Iron uptake from transferrin by isolated hepatocytes: effect of ethanol

Freshly isolated rat hepatocytes incubated with highly purified 59Fe-labelled diferric 125I-rat transferrin for 90 minutes in the presence of 10 mM ethanol took up significantly less 59Fe than did cells incubated without ethanol, while producing a significantly greater reduction of the pH of the incubation medium. Total transferrin binding was equivalent in both groups, but the molecular ratio of iron:transferrin on cell membranes isolated after 90 minutes was markedly reduced in the presence of ethanol, suggesting increased retention of apotransferrin. These data are compatible with the hypothesis that iron uptake from transferrin by hepatocytes is mediated by a pH dependent transferrin receptor mechanism similar to that in reticulocytes.