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Up‐regulation of uncoupling proteins by β‐adrenergic stimulation in L6 myotubes
Author(s) -
Nagase Itsuro,
Yoshida Toshihide,
Saito Masayuki
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02341-9
Subject(s) - ucp3 , uncoupling protein , endocrinology , medicine , skeletal muscle , myogenesis , chemistry , thermogenesis , stimulation , epinephrine , brown adipose tissue , biology , adipose tissue
Catecholamine‐induced and β‐adrenergic receptor (β‐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 β‐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 (β2‐AR agonists), but abolished by propranolol and ICI‐118,551 (β2‐AR antagonists). Pharmacological and mRNA analyses revealed the existence of β2‐AR, but not β1‐ and β3‐ARs, in L6 myotubes. These results suggested that catecholamines up‐regulate UCP2 and UCP3 expression through direct action on the β2‐AR in skeletal muscle.