title: Indispensable role of mitochondrial UCP1 for antiobesity effect of beta3-adrenergic stimulation.
abstract: Mitochondrial uncoupling protein-1 (UCP1) has been thought to be a key molecule for thermogenesis during cold exposure and spontaneous hyperphagia and thereby in the autonomic regulation of energy expenditure and adiposity. However, UCP1 knockout (KO) mice were reported to be cold intolerant but unexpectedly did not get obese even after hyperphagia, implying that UCP1 may not be involved in the regulation of adiposity. Treatment of obese animals with beta3-adrenergic agonists is known to increase lipid mobilization, induce UCP1, and, finally, reduce body fat content. To obtain direct evidence for the role of UCP1 in the anti-obesity effect of beta3-adrenergic stimulation, in the present study, UCP1-KO and wild-type (WT) mice were fed on cafeteria diets for 8 wk and then given a beta3-adrenergic agonist, CL-316,243 (CL), or saline for 2 wk. A single injection of CL increased whole body oxygen consumption and brown fat temperature in WT mice but not in KO mice, and it elicited almost the same plasma free fatty acid response in WT and KO mice. WT and KO mice increased similarly their body and white fat pad weights on cafeteria diets compared with those on laboratory chow. Daily treatment with CL resulted in a marked reduction of white fat pad weight and the size of adipocytes in WT mice, but not in KO mice. Compared with WT mice, KO mice expressed increased levels of UCP2 in brown fat but decreased levels in white fat and comparable levels of UCP3. It was concluded that the anti-obesity effect of beta3-adrenergic stimulation is largely attributable to UCP1, but less to UCP2 and UCP3, and thereby to UCP1-dependent degradation of fatty acids released from white adipose tissue.
authors.affiliation: Dept. of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Inokuma
authors.forename: Yuko
authors.initials: Y
authors.lastname: Okamatsu-Ogura
authors.forename: Asako
authors.initials: A
authors.lastname: Omachi
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Matsushita
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yamashita
authors.forename: Masayuki
authors.initials: M
authors.lastname: Saito
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism; D050154:Adiposity / Q000187:drug effects*; D058667:Adrenergic beta-3 Receptor Agonists; D000818:Animals; D001831:Body Temperature / Q000187:drug effects / Q000235:genetics; D001835:Body Weight / Q000187:drug effects / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D004149:Dioxoles / Q000494:pharmacology*; D002149:Energy Intake / Q000187:drug effects / Q000235:genetics; D004734:Energy Metabolism / Q000187:drug effects / Q000235:genetics; D005230:Fatty Acids, Nonesterified / Q000097:blood; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D007473:Ion Channels; D008066:Lipolysis / Q000187:drug effects / Q000235:genetics; D008099:Liver / Q000033:anatomy & histology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D024101:Mitochondrial Proteins / Q000235:genetics; D009765:Obesity / Q000188:drug therapy*; D009929:Organ Size / Q000187:drug effects / Q000235:genetics; D010101:Oxygen Consumption / Q000187:drug effects / Q000235:genetics; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
chemical_list: D058667:Adrenergic beta-3 Receptor Agonists; D002352:Carrier Proteins; D004149:Dioxoles; D005230:Fatty Acids, Nonesterified; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; C000604372:Ucp1 protein, mouse; C000604390:Ucp2 protein, mouse; C000604393:Ucp3 protein, mouse; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3; C076126:disodium (R,R)-5-(2-((2-(3-chlorophenyl)-2-hydroxyethyl)-amino)propyl)-1,3-benzodioxole-2,3-dicarboxylate