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beta 3-Adrenergic agonist induces a functionally active uncoupling protein in fat and slow-twitch muscle fibers.
- Source :
-
The American journal of physiology [Am J Physiol] 1998 Mar; Vol. 274 (3), pp. E469-75. - Publication Year :
- 1998
-
Abstract
- The mitochondrial uncoupling protein (UCP) has usually been found only in brown adipose tissue. We recently observed that a chronic administration of the beta 3-adrenergic agonist CL-316,243 (CL) induced the ectopic expression of UCP in white fat and skeletal muscle in genetic obese yellow KK mice. The aim of the present study was to examine whether UCP could be induced in nongenetic obese animals produced by neonatal injections of monosodium L-glutamate (MSG). The daily subcutaneous injection of CL (0.1 mg/kg) to MSG-induced obese mice for 2 wk caused significant reductions of body weight (15%) and white fat pad weight (58%). Northern and Western blot analyses showed that CL induced significant expressions of UCP in the white fat and muscle, as well as in brown fat. Immunohistochemical observations revealed that the UCP stains in white fat were localized on multilocular cells and that those in muscle were localized on slow-twitch fibers rich in mitochondria. Immunoelectron microscopy confirmed the mitochondrial localization of UCP in the myocytes. The guanosine 5'-diphosphate (GDP) binding to mitochondria in brown fat doubled after the CL treatment. Moreover, significant GDP binding was detected in the white fat and muscle of the CL-treated mice, at about one-fourth and one-thirteenth the activity of brown fat, respectively, suggesting that ectopically expressed UCP is functionally active. We concluded that the beta 3-adrenergic agonist CL can induce functionally active UCP in white fat and slow-twitch muscle fibers of obese mice.
- Subjects :
- Adipose Tissue metabolism
Animals
Carrier Proteins genetics
Female
Food Additives pharmacology
Guanosine Diphosphate metabolism
Ion Channels
Membrane Proteins genetics
Mice
Mice, Obese
Microscopy, Immunoelectron
Mitochondria, Muscle drug effects
Mitochondria, Muscle metabolism
Mitochondrial Proteins
Muscle Fibers, Slow-Twitch metabolism
Muscle, Skeletal drug effects
Muscle, Skeletal metabolism
Obesity metabolism
RNA, Messenger metabolism
Receptors, Adrenergic, beta drug effects
Receptors, Adrenergic, beta-3
Sodium Glutamate pharmacology
Uncoupling Protein 1
Adipose Tissue drug effects
Adrenergic beta-Agonists pharmacology
Carrier Proteins biosynthesis
Dioxoles pharmacology
Membrane Proteins biosynthesis
Muscle Fibers, Slow-Twitch drug effects
Receptors, Adrenergic, beta metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9513
- Volume :
- 274
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The American journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 9530130
- Full Text :
- https://doi.org/10.1152/ajpendo.1998.274.3.E469