title: Effects of conjugated linoleic acid on liver composition and fatty acid oxidation are isomer-dependent in hamster.
abstract: OBJECTIVE
  The present work was designed to study the effects of the two main isomers of conjugated linoleic acid (CLA), cis-9,trans-11 and trans-10,cis-12, on liver composition and hepatic fatty acid oxidation in hamsters.
  
  
  METHODS
  Animals were divided into three groups that were fed atherogenic diets supplemented with 0.5% linoleic acid, cis-9,trans-11 CLA, or trans-10,cis-12 CLA for 6 wk. Liver lipids, protein, water and DNA contents, and histologic structure were analyzed. Hepatic carnitine palmitoyltransferase-I and acyl coenzyme A oxidase activities were assessed. Triacylglycerol concentration, and aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, and alkaline phosphatase activities were evaluated in serum. CLA isomer contents were analyzed by gas chromatography in hepatic triacylglycerols. Peroxisome proliferator-activated receptor-alpha mRNA was determined by reverse transcriptase polymerase chain reaction.
  
  
  RESULTS
  Trans-10,cis-12 CLA led to significantly greater weight, lower levels of triacylglycerol, cholesterol, and phospholipid, and larger total cell number in liver. Carnitine palmitoyltransferase-I and acyl coenzyme A oxidase activities were significantly increased by this isomer. No changes were induced by cis-9,trans-11 CLA. Trans-10,cis-12 CLA was recovered in significantly lower proportions than cis-9,trans-11 in liver triacylglycerols. Histopathologic analysis showed no abnormalities. No significant differences in serum aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, and alkaline phosphatase activities or in hepatic mRNA peroxisome proliferator-activated receptor-alpha expression were found among the three experimental groups.
  
  
  CONCLUSIONS
  These results suggest that the addition of 0.5% of these CLA isomers to the diet do not induce toxic effects in liver after 6 wk of feeding. Intake of trans-10,cis-12 isomer but not of cis-9,trans-11 CLA increases liver fatty acid oxidation. This effect leads to decreased hepatic and serum triacylglycerols.
authors.affiliation: Department of Nutrition and Food Science, Faculty of Pharmacy, University of País Vasco, Vitoria, Spain.
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Macarulla
authors.forename: Alfredo
authors.initials: A
authors.lastname: Fernández-Quintela
authors.forename: Amaia
authors.initials: A
authors.lastname: Zabala
authors.forename: Virginia
authors.initials: V
authors.lastname: Navarro
authors.forename: Enrique
authors.initials: E
authors.lastname: Echevarría
authors.forename: Itziar
authors.initials: I
authors.lastname: Churruca
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Rodríguez
authors.forename: María P
authors.initials: MP
authors.lastname: Portillo
mesh_terms: D042962:Acyl-CoA Oxidase / Q000187:drug effects / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002334:Carnitine O-Palmitoyltransferase / Q000187:drug effects / Q000378:metabolism; D002849:Chromatography, Gas / Q000379:methods; D006224:Cricetinae; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D007536:Isomerism; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D050356:Lipid Metabolism; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010084:Oxidation-Reduction / Q000187:drug effects; D011506:Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors; D014166:Transferases / Q000097:blood; D014280:Triglycerides / Q000097:blood; D014867:Water / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D044243:Linoleic Acids, Conjugated; D011506:Proteins; D014280:Triglycerides; D014867:Water; D004247:DNA; D042962:Acyl-CoA Oxidase; D014166:Transferases; D002334:Carnitine O-Palmitoyltransferase; D000469:Alkaline Phosphatase