Ghrelin regulates adiposity in white adipose tissue and UCP1 mRNA expression in brown adipose tissue in mice.
To examine the involvement of ghrelin in obesity, we investigated the effects of treatment with peripherally administered ghrelin on food intake, adiposity, and expression of uncoupling protein (UCP) mRNA in brown (BAT) and white (WAT) adipose tissue in mice. Acute bolus administration of ghrelin at a dose of 120 nmol/kg increased cumulative food intake over 4 and 24 h as compared to controls (p<0.05 for each), whereas 12 nmol/kg/day ghrelin showed no remarkable effect (p>0.1). Chronic repeated treatment with 12 nmol/kg/day ghrelin for 7 days increased body weight and adiposity assessed by the weight of adipose tissue, triglyceride content in WAT (p<0.05 for each versus control). In addition, the same treatment decreased and increased mRNA expression of BAT UCP1 and WAT UCP2, respectively (p<0.05 for each). In conclusion, ghrelin can regulate body weight, adiposity and UCPs mRNA expression in mice. The present results provide evidence for a new regulatory loop involving ghrelin and UCP, and add novel insights into the regulatory mechanisms of obesity.
Tsubone
Tetsuo
T
Department of Internal Medicine 1, School of Medicine, Faculty of Medicine, Oita Medical University, 1-1 Idaigaoka, Hasama, Oita 879-5593, Japan.
Masaki
Takayuki
T
Katsuragi
Isao
I
Tanaka
Katsuhiro
K
Kakuma
Tetsuya
T
Yoshimatsu
Hironobu
H
D000273:Adipose Tissue / Q000378:metabolism*; D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001823:Body Composition; D001835:Body Weight; D002352:Carrier Proteins / Q000096:biosynthesis*; D004435:Eating; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005502:Food; D005786:Gene Expression Regulation; D054439:Ghrelin; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D026901:Membrane Transport Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D024101:Mitochondrial Proteins / Q000378:metabolism; D009765:Obesity / Q000378:metabolism; D036361:Peptide Hormones / Q000378:metabolism / Q000494:pharmacology*; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2
D002352:Carrier Proteins; D005230:Fatty Acids, Nonesterified; D054439:Ghrelin; D007328:Insulin; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D036361:Peptide Hormones; D020033:Protein Isoforms; D012333:RNA, Messenger; D014280:Triglycerides; C000604372:Ucp1 protein, mouse; C000604390:Ucp2 protein, mouse; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D005947:Glucose