Abstract
Catecholamine-induced and beta-adrenergic receptor (beta-AR)-mediated thermogenesis in skeletal muscle is a significant component of whole-body energy expenditure. Skeletal muscle expresses uncoupling protein (UCP) 2 and UCP3, which can dissipate the transmitochondrial electrochemical gradient and thereby may be involved in regulation of energy metabolism. We investigated the effects of beta-AR stimulation on UCP2 and UCP3 expression in L6 myotubes. Stimulation of the cells with epinephrine increased the UCP3 mRNA level transiently at 6 h, and also the UCP2 mRNA level at 6-24 h. The stimulatory effects of epinephrine were also observed in the presence of carbacyclin and 9-cis retinoic acid, and mimicked by isoproterenol and salbutamol (beta2-AR agonists), but abolished by propranolol and ICI-118,551 (beta2-AR antagonists). Pharmacological and mRNA analyses revealed the existence of beta2-AR, but not beta1- and beta3-ARs, in L6 myotubes. These results suggested that catecholamines up-regulate UCP2 and UCP3 expression through direct action on the beta2-AR in skeletal muscle.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adrenergic beta-Agonists / pharmacology*
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Adrenergic beta-Antagonists / pharmacology
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Albuterol / pharmacology
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Alitretinoin
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Animals
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Carrier Proteins / genetics*
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Cell Line
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Cyclic AMP / metabolism
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Energy Metabolism
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Epinephrine / pharmacology
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Epoprostenol / analogs & derivatives
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Epoprostenol / pharmacology
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Ion Channels
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Isoproterenol / pharmacology
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Membrane Transport Proteins*
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Mitochondrial Proteins*
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Muscle, Skeletal / cytology
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Muscle, Skeletal / drug effects*
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Muscle, Skeletal / metabolism
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Propanolamines / pharmacology
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Propranolol / pharmacology
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Proteins / genetics*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Rats
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Receptors, Adrenergic, beta / genetics
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Receptors, Adrenergic, beta / metabolism*
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Receptors, Cytoplasmic and Nuclear / metabolism
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Receptors, Retinoic Acid / metabolism
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Retinoid X Receptors
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Time Factors
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Transcription Factors / metabolism
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Tretinoin / pharmacology
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Uncoupling Protein 2
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Uncoupling Protein 3
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Up-Regulation / drug effects*
Substances
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Adrenergic beta-Agonists
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Adrenergic beta-Antagonists
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Carrier Proteins
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Ion Channels
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Membrane Transport Proteins
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Mitochondrial Proteins
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Propanolamines
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Proteins
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RNA, Messenger
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Receptors, Adrenergic, beta
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Receptors, Cytoplasmic and Nuclear
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Receptors, Retinoic Acid
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Retinoid X Receptors
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Transcription Factors
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Ucp2 protein, rat
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Ucp3 protein, rat
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Uncoupling Protein 2
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Uncoupling Protein 3
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Alitretinoin
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ICI 118551
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Tretinoin
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carboprostacyclin
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Propranolol
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Epoprostenol
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Cyclic AMP
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Isoproterenol
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Albuterol
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Epinephrine