Tumor necrosis factor-alpha regulates in vivo expression of the rat UCP family differentially.
A family of uncoupling proteins (UCPs), free fatty acid anion transporters, plays a crucial role in energy homeostatic thermoregulation. Tumor necrosis factor-alpha (TNF-alpha), a member of the cytokine family, is well known as an endogenous pyrogen. To evaluate the interaction of TNF-alpha with UCPs in thermogenesis, effects of TNF-alpha on rat UCP gene expression were examined in intrascapular brown adipose tissue (BAT), epididymal white adipose tissue (WAT) and soleus muscle (Muscle). Administration of TNF-alpha elevated rectal temperature by 0.7 degree C as well as serum leptin which peaked at 6 h, compared with saline controls. BAT UCP1 mRNA expression was increased by 1.2-fold at 6 h after the TNF-alpha treatment and decreased by 0.8-fold at 16 h after the treatment. In contrast to UCP1 expression in BAT, UCP2 mRNA expressions in BAT, WAT, and Muscle was increased to reach maximum levels of 1.3-, 1.6- and 1.8-fold, respectively, at 16 h after the treatment. UCP3 mRNA in Muscle, but not in BAT or WAT, was exclusively up-regulated by 1.7-fold at 16 h after the treatment. These results indicate that TNF-alpha up-regulates UCP gene expression differentially and tissue dependently, and add novel insights into thermogenesis under conditions of malignancy and inflammation.
Masaki
T
T
Department of Internal Medicine 1, School of Medicine, Oita Medical University, Japan.
Yoshimatsu
H
H
Chiba
S
S
Hidaka
S
S
Tajima
D
D
Kakuma
T
T
Kurokawa
M
M
Sakata
T
T
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001833:Body Temperature Regulation / Q000187:drug effects; D002352:Carrier Proteins / Q000235:genetics*; D015342:DNA Probes / Q000235:genetics; D007473:Ion Channels; D020738:Leptin; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014475:Uncoupling Agents / Q000378:metabolism*; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D015854:Up-Regulation / Q000187:drug effects