title: Effects of aging and denervation on the expression of uncoupling proteins in slow- and fast-twitch muscles of rats.
abstract: We investigated the effects of aging and denervation on the gene expression of uncoupling proteins (UCPs) in slow-twitch soleus and fast-twitch gastrocnemius muscles. In a comparison between the control limbs of 6- and 24-month-old rats, the mRNA levels of UCP3, heart-type fatty acid binding protein (HFABP), and glucose transporter-4 (GLUT4) were considerably lower in the gastrocnemius muscles of the older rats, whereas no significant differences in the mRNA levels of those genes as well as UCP2 and cytochrome oxidase subunit IV (COX-IV) were observed in the soleus muscles of young and old rats. The UCP3 and COX-IV protein levels were also reduced considerably in the aged gastrocnemius muscles with atrophy. Denervation of the sciatic nerve caused an increase in UCP3 mRNA levels in both muscles, but the regulation of other genes contrasted between the two types of skeletal muscles. In spite of the increased mRNA level, a remarkable reduction in UCP3 protein was found in the denervated gastrocnemius muscles. These results indicate that the effects of aging and denervation on the gene expression of UCPs, HFABP, GLUT4, and COX-IV are different between the muscle types. The reduction in the mitochondrial UCP3 and COX proteins in aged fast-twitch muscles may have a negative effect on energy metabolism and thermogenesis in old animals.
authors.affiliation: Department of Molecular Genetics, National Institute for Longevity Sciences, and Japan Foundation for Aging and Health, Gengo, Obu 474-8522, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Kontani
authors.forename: Zuocheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Furuyama
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Sato
authors.forename: Nozomu
authors.initials: N
authors.lastname: Mori
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yamashita
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005786:Gene Expression Regulation; D051275:Glucose Transporter Type 4; D006706:Homeostasis; D007473:Ion Channels; D008297:Male; D024101:Mitochondrial Proteins; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D009121:Muscle Denervation; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000166:cytology / Q000294:innervation / Q000378:metabolism; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D051381:Rats; D011916:Rats, Inbred F344; D014475:Uncoupling Agents / Q000378:metabolism*; D000071247:Uncoupling Protein 3
chemical_list: D002352:Carrier Proteins; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D051275:Glucose Transporter Type 4; D007473:Ion Channels; D024101:Mitochondrial Proteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; C495694:Slc2a4 protein, rat; C000604394:Ucp3 protein, rat; D014475:Uncoupling Agents; D000071247:Uncoupling Protein 3; D003576:Electron Transport Complex IV