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.
Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.
MeSH terms
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Adaptation, Physiological* / genetics
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Adipose Tissue, Brown / cytology
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Adipose Tissue, Brown / metabolism
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Adipose Tissue, Brown / physiology*
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Animals
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Body Temperature Regulation / genetics
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Cold Temperature*
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Epinephrine / deficiency*
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Epinephrine / pharmacology
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Epinephrine / physiology
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Gene Expression Regulation / drug effects
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Ion Channels / genetics
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Ion Channels / metabolism
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Lipid Metabolism / genetics
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Male
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Mice
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Mice, Knockout
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Mitochondrial Proteins / genetics
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Mitochondrial Proteins / metabolism
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Phenylethanolamine N-Methyltransferase / genetics
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Phenylethanolamine N-Methyltransferase / metabolism
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Temperature
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Thyroid Function Tests
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Time Factors
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Triiodothyronine / blood
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Uncoupling Protein 1
Substances
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Ion Channels
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Mitochondrial Proteins
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Transcription Factors
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Ucp1 protein, mouse
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Uncoupling Protein 1
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peroxisome-proliferator-activated receptor-gamma coactivator-1
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Triiodothyronine
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Phenylethanolamine N-Methyltransferase
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Epinephrine