Conjugated linoleic acid causes a marked increase in liver alpha-tocopherol and liver alpha-tocopherol transfer protein in C57BL/6 J mice.
Conjugated linoleic acid (CLA) is a collective term for the positional and geometric isomers of a conjugated diene of linoleic acid (C18:2, n-6). The aims of the present study were to evaluate whether levels of hepatic alpha-tocopherol, alpha-tocopherol transfer protein (alpha-TTP), and antioxidant enzymes in mice were affected by a CLA-supplemented diet. C57BL/6 J mice were divided into the CLA and control groups, which were fed, respectively, a 5 % fat diet with or without 1 g/100 g of CLA (1:1 mixture of cis-9, trans-11 and trans-10, cis-12) for four weeks. alpha-Tocopherol levels in plasma and liver were significantly higher in the CLA group than in the control group. Liver alpha-TTP levels were also significantly increased in the CLA group, the alpha-TTP/beta-actin ratio being 2.5-fold higher than that in control mice (p<0.01). Thiobarbituric acid-reactive substances were significantly decreased in the CLA group (p<0.01). There were no significant differences between the two groups in levels of three antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and catalase). The accumulation of liver alpha-tocopherol seen with the CLA diet can be attributed to the antioxidant potential of CLA and the ability of alpha-TTP induction. The lack of changes in antioxidant enzyme protein levels and the reduced lipid peroxidation in the liver of CLA mice are due to alpha-tocopherol accumulation.
Institute of Nutrition and Department of Nutrition, China Medical University, Taichung, Taiwan.
Pei-Min
PM
Chao
Wan-Hsuan
WH
Chen
Chun-Huei
CH
Liao
Huey-Mei
HM
Shaw
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004032:Diet; D019587:Dietary Supplements; D005979:Glutathione Peroxidase / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000008:administration & dosage* / Q000737:chemistry; D015227:Lipid Peroxidation; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism; D015854:Up-Regulation; D015430:Weight Gain; D024502:alpha-Tocopherol / Q000097:blood / Q000378:metabolism*; D024504:gamma-Tocopherol / Q000378:metabolism
D002352:Carrier Proteins; D044243:Linoleic Acids, Conjugated; D017392:Thiobarbituric Acid Reactive Substances; D014280:Triglycerides; C017763:alpha-tocopherol transfer protein; D024504:gamma-Tocopherol; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D024502:alpha-Tocopherol