Effects of trans-10,cis-12 CLA on liver size and fatty acid oxidation under energy restriction conditions in hamsters.
OBJECTIVE
Little evidence exists concerning the effects of trans-10,cis-12 conjugated linoleic acid (CLA) under energy restriction. Thus, the effects of this CLA isomer on adipose tissue size, liver composition, as well as on expression and activity of carnitine-palmitoyl transferase I (CPT-I) and acyl CoA oxidase (ACO), in hamsters fed an energy-restricted diet were analyzed.


METHODS
Hamsters were fed a high-fat diet for 7 wk and then subjected to 25% energy-restricted diets supplemented with 0.5% linoleic acid or 0.5% trans-10,cis-12 CLA for 3 wk. Serum insulin, free-triiodothyronine and non-esterified fatty acid levels, liver triacylglycerol, protein and water contents, and CPT-I, ACO, and Peroxisome proliferator-activated receptor alpha (PPARα) expressions and enzyme activities were assessed.


RESULTS
Energy restriction reduced liver size, serum levels of insulin, free-triiodothyronine, and non-esterified fatty acid and increased CPT-I activity. Liver composition was not modified. No differences were found between both restricted groups, with the exception of CPT-I and ACO oxidative enzyme activities, which were greater in hamsters fed the CLA diet.


CONCLUSIONS
Energy restriction does not cause trans-10,cis-12 CLA to induce liver hyperplasia. Although this CLA isomer increases liver CPT-I and ACO activities, this effect does not result in reduced hepatic triacylglyerol content or decreased adipose tissue size. Consequently, this CLA isomer seems not to be a useful tool for inclusion in body weight loss strategies followed during obesity treatment.
Lasa
Arrate
A
Department of Nutrition and Food Science, University of País Vasco, Vitoria, Spain.
Simón
Edurne
E
Department of Nutrition and Food Science, University of País Vasco, Vitoria, Spain.
Churruca
Itziar
I
Department of Nutrition and Food Science, University of País Vasco, Vitoria, Spain.
Fernández-Quintela
Alfredo
A
Department of Nutrition and Food Science, University of País Vasco, Vitoria, Spain.
Macarulla
María Teresa
MT
Department of Nutrition and Food Science, University of País Vasco, Vitoria, Spain.
Martínez
J Alfredo
JA
Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain.
Portillo
María Puy
MP
Department of Nutrition and Food Science, University of País Vasco, Vitoria, Spain. Electronic address: mariapuy.portillo@ehu.es.
D042962:Acyl-CoA Oxidase / Q000378:metabolism*; D000818:Animals; D031204:Caloric Restriction; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism*; D006224:Cricetinae; D004041:Dietary Fats / Q000009:adverse effects; D019587:Dietary Supplements; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006965:Hyperplasia; D007328:Insulin / Q000097:blood; D007536:Isomerism; D019787:Linoleic Acid / Q000494:pharmacology; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008647:Mesocricetus; D009765:Obesity / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D014284:Triiodothyronine / Q000097:blood
D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D044243:Linoleic Acids, Conjugated; D014284:Triiodothyronine; D019787:Linoleic Acid; D042962:Acyl-CoA Oxidase; D002334:Carnitine O-Palmitoyltransferase