Fatty acid-binding protein: a major contributor to the ethanol-induced increase in liver cytosolic proteins in the rat.
To study the acute and chronic effects of ethanol on hepatic fatty acid-binding protein, rats were pair-fed with liquid diets containing 36% of energy either as ethanol or as additional carbohydrate for 4 to 5 weeks. Animals were killed 90 min after intragastric administration of diets with or without ethanol. Alcohol feeding markedly increased liver triglycerides, with a modest rise in nonesterified fatty acids. Alcohol-fed rats developed hepatomegaly, with a 48% increase in hepatic cytosolic proteins. Fatty acid binding was first assessed by the kinetics of [14C]palmitate binding to cytosolic proteins. The maximal binding capacity more than doubled in the cytosol of the ethanol-fed rats compared to pair-fed controls, whereas the dissociation constant increased by 64%. Acute ethanol administration (3 gm per kg body weight) either to ethanol-fed or control rats did not have a significant effect. To identify the fatty acid-binding protein, labeled cytosolic proteins were fractionated by gel filtration: most of the cytosolic fatty acids eluted as a single peak in the 12,000 to 18,000 molecular weight region corresponding to the hepatic fatty acid-binding protein. The increase in this protein, confirmed by radial immunodiffusion (27.0 +/- 1.4 mg per 100 gm body weight vs. 11.2 +/- 1.6, in controls; p less than 0.01), accounted for 22% of the total rise in cytosolic protein induced by chronic ethanol feeding.
D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000378:metabolism*; D002850:Chromatography, Gel; D003600:Cytosol / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology*; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005779:Immunodiffusion; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000378:metabolism
D002352:Carrier Proteins; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D014280:Triglycerides; D000431:Ethanol