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Background: It is common for alcoholic patients to have excess iron accumulation in the liver, which may contribute to the development of alcoholic liver disease (ALD). However, the mechanism of hepatic iron uptake in ALD is still obscure. Recently, a novel iron-regulatory hormone hepcidin was found that suppresses the absorption of iron from the small intestine and the release of iron from macrophages. To elucidate the contribution of hepcidin toward the hepatic excess iron accumulation in ALD, we examined whether alcohol loading affects hepcidin expression both in ALD patients and in an ethanol-fed mouse model., Methods: Serum prohepcidin concentration was quantified by enzyme-linked immunosorbent assay. Hepatic hepcidin-1 and hepcidin-2 mRNA expressions in mouse liver were evaluated by quantitative real-time reverse-transcriptase polymerase chain reaction method. The protein expression of prohepcidin in mouse liver was examined immunohistochemically by rabbit antimouse prohepcidin antibody., Results: Serum prohepcidin concentration in ALD was significantly lower than that in healthy subjects (p<0.001). Especially, serum prohepcidin concentrations were decreased in the patients whose serum ferritin value was high. In the ethanol-fed mouse model, hepatic hepcidin-1 mRNA expression was significantly lower than that in control (p=0.04). Prohepcidin was expressed in the cytoplasm of hepatocytes of mice liver tissue sections, and its expression was decreased after ethanol loading., Conclusion: Alcohol loading down-regulates hepatic hepcidin expression and leads to the increase of iron absorption from the intestine.

Chronic alcohol intake is often associated with alterations to iron homeostasis and an increase in the serum levels of carbohydrate-deficient transferrin. As the liver is a major iron storage site and also synthesizes transferrin, the normal serum iron transport protein, the aim of this study was to test the hypothesis that these disturbances in iron homeostasis were caused by altered hepatocyte iron uptake from the abnormal transferrin. To achieve this, we have investigated iron uptake from both transferrin and asialotransferrin by hepatocytes from male Sprague-Dawley rats fed the De Carli and Lieber alcohol diet. Iron uptake from transferrin by hepatocytes from alcoholic rats was less than 60% that of control values, and in the presence of 50 mM ethanol decreased still further to 35% of the uptake by the corresponding control cells. Iron uptake from rat asialotransferrin was reduced in both groups when compared to that observed from normal transferrin; 13% by control cells and 39% by hepatocytes from alcohol-fed rats. Alcohol, however, had no further effect on asialotransferrin uptake by either hepatocytes from alcohol-fed rats, or their pair-fed controls. Transferrin binding to hepatocytes was also influenced by the alcohol diet. Although there was no difference in binding at 37 degrees C, cells from alcohol-fed rats bound 85% of this total at 4 degrees C, compared to 44% by control hepatocytes. Similar values were also obtained for hepatocyte binding of asialotransferrin; alcohol feeding resulted in an increase in binding at 4 degrees C to 73% from 58% with control cells.(ABSTRACT TRUNCATED AT 250 WORDS)