title: Repeated immobilization stress increases uncoupling protein 1 expression and activity in Wistar rats.
abstract: Repeat immobilization-stressed rats are leaner and have improved cold tolerance due to enhancement of brown adipose tissue (BAT) thermogenesis. This process likely involves stress-induced sympathetic nervous system activation and adrenocortical hormone release, which dynamically enhances and suppresses uncoupling protein 1 (UCP1) function, respectively. To investigate whether repeated immobilization influences UCP1 thermogenic properties, we assessed UCP1 mRNA, protein expression, and activity (GDP binding) in BAT from immobilization-naive or repeatedly immobilized rats (3 h daily for 4 weeks) and sham operated or adrenalectomized (ADX) rats. UCP1 properties were assessed before (basal) and after exposure to 3 h of acute immobilization. Basal levels of GDP binding and UCP1 expression was significantly increased (140 and 140%) in the repeated immobilized group. Acute immobilization increased GDP binding in both naive (180%) and repeated immobilized groups (220%) without changing UCP1 expression. In ADX rats, basal GDP binding and UCP1 gene expression significantly increased (140 and 110%), and acute immobilization induced further increase. These data demonstrate that repeated immobilization resulted in enhanced UCP1 function, suggesting that enhanced BAT thermogenesis contributes to lower body weight gain through excess energy loss and an improved ability to maintain body temperature during cold exposure.
authors.affiliation: Department of Physiology 1, Asahikawa Medical University School of Medicine, Midorigaoka-higashi 2-1-1-1, Asahikawa, 078-8510 Japan.
authors.forename: Bihu
authors.initials: B
authors.lastname: Gao
authors.forename: Kazue
authors.initials: K
authors.lastname: Kikuchi-Utsumi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohinata
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kuroshima
mesh_terms: D002001:Adipose Tissue, Brown / Q000378:metabolism; D000315:Adrenalectomy; D000818:Animals; D001831:Body Temperature; D001835:Body Weight; D002352:Carrier Proteins / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood; D004435:Eating; D006153:Guanosine Diphosphate / Q000378:metabolism; D007103:Immobilization; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D051381:Rats; D017208:Rats, Wistar; D012008:Recurrence; D013312:Stress, Physiological / Q000209:etiology / Q000378:metabolism*; D000071256:Uncoupling Protein 1
chemical_list: D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D006153:Guanosine Diphosphate; D003345:Corticosterone