title: Effect of epinephrine deficiency on cold tolerance and on brown adipose tissue.
abstract: 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.
authors.affiliation: 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
authors.forename: Rana I
authors.initials: RI
authors.lastname: Sharara-Chami
authors.forename: Maria
authors.initials: M
authors.lastname: Joachim
authors.forename: Michelle
authors.initials: M
authors.lastname: Mulcahey
authors.forename: Steven
authors.initials: S
authors.lastname: Ebert
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Majzoub
mesh_terms: 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
chemical_list: 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