title: Bidirectional regulation of uncoupling protein-3 and GLUT-4 mRNA in skeletal muscle by cold.
abstract: To elucidate the possible role of the mitochondrial uncoupling protein (UCP)-3 in skeletal muscle as a regulator of adaptive thermogenesis and energy balance, we examined the modulation by cold exposure (5 degrees C) of UCP-3 and glucose transporter isoform GLUT-4 mRNAs in male Sprague-Dawley rats. In skeletal muscle, UCP-3 and GLUT-4 mRNAs increased two- to threefold between 6 and 24 h of cold exposure and then decreased to 50% of the control value after 6 days in the cold. In contrast, skeletal muscle UCP-2 mRNA showed a small increase on day 3 and returned to normal after 6 days. The bidirectional regulation of UCP-3 and GLUT-4 mRNAs in skeletal muscle by cold suggests that UCP-3 may be a major mediator of acute adaptive thermogenesis but then is downregulated, along with GLUT-4, in the chronic state to preserve energy. In contrast, cold exposure caused only transient changes of UCP-2 and GLUT-4 mRNA in heart. These data are consistent with the necessity of the heart to continuously expend energy to maintain blood circulation, regardless of environmental conditions.
authors.affiliation: Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 01228, USA.
authors.forename: B
authors.initials: B
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Coughlin
authors.forename: P F
authors.initials: PF
authors.lastname: Pilch
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D003001:Cloning, Molecular; D003080:Cold Temperature; D005786:Gene Expression Regulation / Q000502:physiology*; D051275:Glucose Transporter Type 4; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007473:Ion Channels; D008297:Male; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000378:metabolism; D024101:Mitochondrial Proteins; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis / Q000235:genetics*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000502:physiology*; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000096:biosynthesis; D012795:Sialoglycoproteins / Q000096:biosynthesis / Q000235:genetics; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
chemical_list: D002352:Carrier Proteins; D051275:Glucose Transporter Type 4; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007473:Ion Channels; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D011506:Proteins; D011994:Recombinant Proteins; C495692:SLC2A4 protein, human; D012795:Sialoglycoproteins; C495694:Slc2a4 protein, rat; C000604389:UCP2 protein, human; C000604392:UCP3 protein, human; C000604391:Ucp2 protein, rat; C000604394:Ucp3 protein, rat; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3