Induction of transferrin receptor by ethanol in rat primary hepatocyte culture.
BACKGROUND
It is not uncommon for alcoholics to have iron accumulation in the liver, a condition that may contribute to the development of alcoholic liver disease. Recently, we reported that the expression of transferrin receptor, which mediates cellular iron uptake, was increased in hepatocytes in patients with alcoholic liver disease. To elucidate the mechanism of the iron accumulation in hepatocytes in such disease, we examined whether ethanol exposure induced the transferrin receptor expression and increased the cellular iron uptake.


METHODS
Rat primary hepatocytes were isolated and cultured in the presence of 20 micromol/liter of iron and 25 mmol/liter of ethanol.


RESULTS
Ethanol exposure to the hepatocytes demonstrated an ~2-fold increase in transferrin receptor expression for 24 hr, shown by Western blot analysis and S-methionine metabolic labeling, 19% increase in Fe-transferrin uptake by hepatocytes, and 20% increase in activity of iron regulatory protein examined by band shift assay.


CONCLUSIONS
Ethanol exposure induced the transferrin receptor expression, partially through the activation of iron regulatory protein, and increased the transferrin-bound iron uptake in rat hepatocyte cultures. The induction of transferrin receptor by ethanol might be one of the mechanisms of iron accumulation in the hepatocytes in alcoholic liver disease.
Third Department of Internal Medicine, Asahikawa Medical College, Asahikawa, Japan.
Masako
M
Suzuki
Yoshinori
Y
Fujimoto
Yasuaki
Y
Suzuki
Yayoi
Y
Hosoki
Hiroyuki
H
Saito
Kenji
K
Nakayama
Takaaki
T
Ohtake
Yutaka
Y
Kohgo
D000818:Animals; D002478:Cells, Cultured; D000431:Ethanol / Q000494:pharmacology*; D005290:Ferric Compounds / Q000494:pharmacology; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011990:Receptors, Transferrin / Q000096:biosynthesis* / Q000235:genetics
D005290:Ferric Compounds; D011990:Receptors, Transferrin; D000431:Ethanol; C025314:ferric citrate