Lipids

, Volume 41, Issue 2, pp 179–188

Conjugated linoleic acid reduces hepatic steatosis, improves liver function, and favorably modifies lipid metabolism in obese insulin-resistant rats

  • Amy Noto
  • Peter Zahradka
  • Natalia Yurkova
  • Xueping Xie
  • Evan Nitschmann
  • Malcolm Ogborn
  • Carla G. Taylor
Article

DOI: 10.1007/s11745-006-5086-6

Cite this article as:
Noto, A., Zahradka, P., Yurkova, N. et al. Lipids (2006) 41: 179. doi:10.1007/s11745-006-5086-6

Abstract

CLA has been shown to induce or suppress excess liver lipid accumulation in various animal models. Interestingly, the state of insulin resistance may be an important modulator of this effect. The objective of the current study was to determine how feeding a dietary CLA mixture would affect liver lipid accumulation in insulin-resistant/obese and lean rats in relation to liver function, lipidemia, liver TAG and phospholipid FA composition, and expression of hepatic markers of FA transport, oxidation, and synthesis. Six-week-old fa/fa and lean Zucker rats (n=20/genotype) were fed either a 1.5% CLA mixture or a control diet for 8 wk. CLA supplementation reduced liver lipid concentration of fa/fa rats by 62% in concurrence with improved liver function (lower serum alanine aminotransferase and alkaline phosphatase) and favorable modification of the serum lipoprotein profile (reduced VLDL and LDL and elevated HDL) compared with control-fed fa/fa rats. The fa/fa genotype had two-thirds the amount of CLA (as % total FA) incorporated into liver TAG and phospholipids compared with the lean genotype. In both genotypes, CLA altered the hepatic FA profile (TAG greater than phospholipids) and these changes were explained by a desaturase enzyme index. Liver-FA-binding protein and acyl CoA oxidase, markers of FA transport and oxidation, respectively, were expressed at higher levels in CLA-fed fa/fa rats. In summary, these results illustrate a strong relationship between the state of insulin resistance and liver lipid metabolism and suggest that CLA acts to favorably modify lipid metabolism in fa/fa Zucker rats.

Abbreviations

ACC

acetyl CoA carboxylase

ACO

acyl CoA oxidase

ALT

alanine aminotransferase

CTL

control

fa

fa/fa Zucker rats

L-FABP

liver-fatty acid binding protein

In

lean Zucker rats

mHCl

methanolic hydrochloric acid

MUFA

monounsaturated FA

NAFLD

nonalcoholic fatty liver disease

OLETF

Otsuka Long Evans Tokushima Fatty

PPAR

peroxisome proliferators-activated receptor

RT-PCR

reverse transcriptase polymerase chain reaction

PL

phospholipids

SCD1

stearoyl CoA desaturase 1

SFA

saturated FA

SREBP-1

sterol regulatory binding protein-1

ZDF

Zucker Diabetic Fatty

Copyright information

© AOCS Press 2006

Authors and Affiliations

  • Amy Noto
    • 1
  • Peter Zahradka
    • 2
  • Natalia Yurkova
    • 2
  • Xueping Xie
    • 2
  • Evan Nitschmann
    • 3
  • Malcolm Ogborn
    • 3
  • Carla G. Taylor
    • 1
  1. 1.Department of Human Nutritional SciencesUniversity of ManitobaWinnipegCanada
  2. 2.Department of PhysiologyUniversity of ManitobaWinnipegCanada
  3. 3.Department of Pediatrics and Child HealthUniversity of ManitobaWinnipegCanada