Weak effect of trans-10, cis-12-conjugated linoleic acid on body fat accumulation in adult hamsters.
It has been proposed that young animals and subjects are more responsive to conjugated linoleic acid (CLA) than the adults. Nevertheless, there is very little information concerning the effectiveness of CLA in adult animals. In the present study we aimed to explore the effects of trans-10, cis-12-CLA on body fat accumulation in adult hamsters, as well as on some of the molecular mechanisms described in young animals as responsible for the CLA body fat-lowering effect, such as lipogenesis, lipoprotein lipase (LPL)-mediated fat uptake and thermogenesis. The experiment was conducted with sixteen adult male Syrian Golden hamsters (aged 8 months) fed a high-fat diet supplemented or not with 0.5 % trans-10, cis-12-CLA for 6 weeks. Acetyl-CoA carboxylase (ACX), fatty acid synthase (FAS), LPL, PPARgamma, sterol regulatory element-binding protein (SREBP)-1a and SREBP-1c expressions were assessed in subcutaneous and perirenal adipose tissues by real-time RT-PCR. Total and heparin-releasable LPL activities were determined in subcutaneous adipose tissue by fluorimetry and FAS activity by spectrophotometry. Uncoupling protein-1 (UCP1) expression in interscapular brown adipose tissue was assessed by Western blot. Hamsters fed the trans-10, cis-12-CLA diet showed a significant reduction in subcutaneous adipose tissue. No changes were observed in the expression of ACX, FAS, LPL, SREBP-1a, SREBP-1c and PPARgamma, nor in total and heparin-releasable LPL and FAS activities. Trans-10, cis-12-CLA induced a significant increase in the amount of UCP1. These results suggest a low responsiveness to trans-10, cis-12-CLA in adults, lower than that in young hamsters. One of the reasons explaining this difference is the lack of effect on LPL.
Miranda
Jonatan
J
Department of Nutrition and Food Science, University of País Vasco, Paseo de la Universidad 7, Vitoria, Spain.
Churruca
Itziar
I
Fernández-Quintela
Alfredo
A
Rodríguez
Victor Manuel
VM
Macarulla
María Teresa
MT
Simón
Edurne
E
Portillo
María Puy
MP
D000273:Adipose Tissue / Q000187:drug effects* / Q000201:enzymology; D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism; D052436:Adipose Tissue, White / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D006224:Cricetinae; D004435:Eating / Q000187:drug effects / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic; D007473:Ion Channels / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D050155:Lipogenesis / Q000187:drug effects; D008297:Male; D008647:Mesocricetus; D024101:Mitochondrial Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D050151:Subcutaneous Fat / Q000201:enzymology; D014157:Transcription Factors / Q000378:metabolism; D000071256:Uncoupling Protein 1
D007473:Ion Channels; D044243:Linoleic Acids, Conjugated; D024101:Mitochondrial Proteins; D014157:Transcription Factors; D000071256:Uncoupling Protein 1; C496197:trans-10,cis-12-conjugated linoleic acid