Formation of the 37-kD protein-acetaldehyde adduct in primary cultured rat hepatocytes exposed to alcohol.
We have previously reported that a 37-kD liver protein formed an adduct with acetaldehyde in vivo when rats were fed alcohol chronically. To understand the mechanism of the formation of this protein-acetaldehyde adduct, rat hepatocytes in primary culture were treated with ethanol in vitro for several days. When cultured in hormone-enriched and trace metal-enriched Waymouth's medium, alcohol dehydrogenase activities in hepatocytes decreased only about 30% during 6 days of culture. At the end of the specified time, protein extracts of hepatocytes were immunotransblotted with rabbit immunoglobulin G that recognized acetaldehyde adduct as an epitope. The 37-kD protein-acetaldehyde adduct band could be detected within 3 days in cells that had been treated with alcohol at a steady-state concentration as low as 5 mmol/L. Although the maximal intensity was obtained at approximately 10 to 40 mmol/L ethanol, addition of cyanamide (an inhibitor of aldehyde dehydrogenase) further increased the intensity of this protein-acetaldehyde adduct band by more than twofold. A good correlation existed between acetaldehyde concentration in the medium and the intensity of the 37-kD protein-acetaldehyde adduct band. Formation of the 37-kD liver protein-acetaldehyde adduct is thus dependent on acetaldehyde, and the 37-kD protein is apparently unusually susceptible to chemical modification by acetaldehyde.
Lin
R C
RC
Department of Medicine, Indiana University School of Medicine, Indianapolis 46223.
Fillenwarth
M J
MJ
Minter
R
R
Lumeng
L
L
D000079:Acetaldehyde / Q000032:analysis / Q000378:metabolism*; D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media; D003484:Cyanamide / Q000494:pharmacology; D003720:Densitometry; D000431:Ethanol / Q000378:metabolism / Q000494:pharmacology*; D015151:Immunoblotting; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D010084:Oxidation-Reduction; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D003470:Culture Media; D011506:Proteins; D000431:Ethanol; D003484:Cyanamide; D000426:Alcohol Dehydrogenase; D000079:Acetaldehyde