Effect of epinephrine deficiency on cold tolerance and on brown adipose tissue.
Catecholamines are involved in thermogenesis. We investigated the specific role of epinephrine in regulation of temperature homeostasis in mice. We subjected adult wildtype (WT) and phenylethanolamine N-methyl transferase knock out mice (Pnmt(-/-)) lacking epinephrine to cold for 24h. Body temperature and thyroid hormone levels were not different between WT and Pnmt(-/-) mice. Although temperature was normal in Pnmt(-/-) mice, the brown fat response to cold was abnormal with no increase in Ucp-1 or Pgc-1alpha mRNA levels (but with an exaggerated cold-induced lipid loss from the tissue). Our results show that epinephrine may have a role in brown fat mitochondrial uncoupling through regulation of Ucp-1 and Pgc-1alpha, although this is not required to maintain a normal temperature during acute cold exposure. We conclude that epinephrine may have an important role in induction of Ucp-1 and Pgc-1alpha gene expression during cold stress.
Sharara-Chami
Rana I
RI
Division of Critical Care Medicine, Department of Anesthesiology, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, United States. rana.chami@childrens.harvard.edu
Joachim
Maria
M
Mulcahey
Michelle
M
Ebert
Steven
S
Majzoub
Joseph A
JA
D000222:Adaptation, Physiological / Q000235:genetics; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001833:Body Temperature Regulation / Q000235:genetics; D003080:Cold Temperature; D004837:Epinephrine / Q000172:deficiency* / Q000494:pharmacology / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D050356:Lipid Metabolism / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D010625:Phenylethanolamine N-Methyltransferase / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D013960:Thyroid Function Tests; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014284:Triiodothyronine / Q000097:blood; D000071256:Uncoupling Protein 1
D007473:Ion Channels; D024101:Mitochondrial Proteins; D014157:Transcription Factors; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; C111264:peroxisome-proliferator-activated receptor-gamma coactivator-1; D014284:Triiodothyronine; D010625:Phenylethanolamine N-Methyltransferase; D004837:Epinephrine