Lipids

, Volume 35, Issue 1, pp 91–98

Effects of conjugated linoleic acid isomers on lipid-metabolizing enzymes in male rats

  • Jean-Charles Martin
  • Stéphane Grégoire
  • Marie-Hélène Siess
  • Martine Genty
  • Jean-Michel Chardigny
  • Olivier Berdeaux
  • Pierre Juaneda
  • Jean-Louis Sébédio
Article

DOI: 10.1007/s11745-000-0499-9

Cite this article as:
Martin, J., Grégoire, S., Siess, M. et al. Lipids (2000) 35: 91. doi:10.1007/s11745-000-0499-9

Abstract

Male weanling Wistar rats (n=15), weighing 200–220 g, were allocated for 6 wk to diets containing 1% (by weight) of conjugated linoleic acid (CLA), either as the 9c,11t-isomer, the 10t,12c-isomer, or as a mixture containing 45% of each of these isomers. The five rats of the control group received 1% of oleic acid instead. Selected enzyme activities were determined in different tissues after cellular subfractionation. None of the CLA-diet induced a hepatic peroxisome-proliferation response, as evidenced by a lack of change in the activity of some characteristic enzymes [i.e., acyl-CoA oxidase, CYP4A1, but also carnitine palmitoyltransferase-I (CPT-I)] or enzyme affected by peroxisome-proliferators (glutathione S-transferase). In addition to the liver, the activity of the rate-limiting β-oxidation enzyme in mitochondria, CPT-I, did not change either in skeletal muscle or in heart. Conversely, its activity increased more than 30% in the control value in epididymal adipose tissue of the animals fed the CLA-diets containing the 10t,12c-isomer. Conversely, the activity of phosphatidate phosphohydrolase, a rate-limiting enzyme in glycerolipid neosynthesis, remained unchanged in adipose tissue. Kinetic studies conducted on hepatic CPT-I and peroxisomal acyl-CoA oxidase with CoA derivatives predicted a different channeling of CLA isomers through the mitochondrial or the peroxisomal oxidation pathways. In conclusion, the 10t,12c-CLA isomer seems to be more efficiently utilized by the cells than its 9c,11t homolog, though the Wistar rat species appeared to be poorly responsive to CLA diets for the effects measured.

Abbreviations

ACO

acyl-CoA oxidase

CLA

conjugated linoleic acid

CPT

carnitine palmitoyl transferase

CYP

cytochrome P450

OD

optical density

PAP

phosphatidate phosphohydrolase

Copyright information

© AOCS Press 2000

Authors and Affiliations

  • Jean-Charles Martin
    • 1
  • Stéphane Grégoire
    • 1
  • Marie-Hélène Siess
    • 2
  • Martine Genty
    • 1
  • Jean-Michel Chardigny
    • 1
  • Olivier Berdeaux
    • 1
  • Pierre Juaneda
    • 1
  • Jean-Louis Sébédio
    • 1
  1. 1.Unité de Nutrition LipidiqueI.N.R.A.Dijon CedexFrance
  2. 2.Laboratoire de Toxicologie NutritionnelleI.N.R.A.Dijon CedexFrance
  3. 3.Laboratoire de Physiologie de la NutritionUniversité de Paris SudOrsayFrance