title: Differential response of UCP3 to medium versus long chain triacylglycerols; manifestation of a functional adaptation.
abstract: We compared UCP3 protein in rat cardiac, glycolytic and oxidative skeletal muscle and examined the effect of high-fat medium chain vs. long chain triacylglycerol feeding on UCP3 content in these tissues. Cardiac muscle displays the lowest basal levels of UCP3 protein. Increasing long chain - but not medium chain - fatty acid supply upregulates UCP3 in all muscles. Since plasma non-esterified fatty acids and the expression of two peroxisome proliferator-activated receptor (PPAR)-responsive genes, were not different between groups, we conclude that the differential upregulation of UCP3 is not merely PPAR-mediated. This study supports a role of UCP3 in export of non-metabolizable fatty acids.
authors.affiliation: Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands. j.hoeks@hb.unimaas.nl
authors.forename: Joris
authors.initials: J
authors.lastname: Hoeks
authors.forename: Matthijs K C
authors.initials: MK
authors.lastname: Hesselink
authors.forename: Marc
authors.initials: M
authors.lastname: van Bilsen
authors.forename: Gert
authors.initials: G
authors.lastname: Schaart
authors.forename: Ger J
authors.initials: GJ
authors.lastname: van der Vusse
authors.forename: Wim H M
authors.initials: WH
authors.lastname: Saris
authors.forename: Patrick
authors.initials: P
authors.lastname: Schrauwen
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D002352:Carrier Proteins / Q000096:biosynthesis*; D002149:Energy Intake / Q000187:drug effects / Q000502:physiology; D007473:Ion Channels; D008297:Male; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D000071247:Uncoupling Protein 3; D015854:Up-Regulation
chemical_list: D002352:Carrier Proteins; D007473:Ion Channels; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D014280:Triglycerides; C000604392:UCP3 protein, human; C000604394:Ucp3 protein, rat; D000071247:Uncoupling Protein 3