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Insulin and contraction directly stimulate UCP2 and UCP3 mRNA expression in rat skeletal muscle in vitro.
- Source :
-
Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2001 Apr 27; Vol. 283 (1), pp. 19-25. - Publication Year :
- 2001
-
Abstract
- To study the regulation of the mitochondrial uncoupling protein 2 and 3 (UCP2 and UCP3), we studied the effect of insulin and muscle contraction on UCP mRNA expression in rat skeletal muscle in vitro. Insulin dose-dependently increased skeletal muscle UCP2 and UCP3 mRNA expression in m. extensor digitorum longus (EDL) with maximal stimulation obtained at around 0.6-6 nM. The concentration of insulin giving half-maximal stimulation was 60 pM for the UCP2 and 48 pM for the UCP3 mRNA expression. The effect of insulin was maximal after 2 h and the effect was sustained during the whole study period (6 h). The insulin-induced increase in UCP mRNA was independent of the glucose uptake (as UCP mRNA was stimulated even in incubations without glucose). In addition, electrically induced contractions (in vitro) increased UCP2 and UCP3 mRNA expression 60-120 min after a single bout of contraction (for 10 min). Both the increment of UCP2 and UCP3 mRNA were sustained throughout the study period (4 h) (153 +/- 62 and 216 +/- 71% above basal, P < 0.05 respectively). Finally, 5-aminoimidazole-4-carboxamid-ribosid (AICAR), an activator of the AMP-activated protein kinase (AMPK), that is activated during exercise, was able to mimic the increase in UCP2 and UCP3 mRNA expression. In conclusion, UCP2 and UCP3 mRNA expression in skeletal muscle are stimulated rapidly by insulin and contraction in vitro, thus the stimulation is direct and not caused by changes in other hormones or metabolites. Even a brief bout of contraction induces an increase in UCP2 and UCP3 expression, an effect that could be mimicked by activation of the AMP-activated protein kinase by AICAR.<br /> (Copyright 2001 Academic Press.)
- Subjects :
- AMP-Activated Protein Kinases
Adrenergic beta-Agonists pharmacology
Aminoimidazole Carboxamide pharmacology
Animals
Carrier Proteins genetics
Dose-Response Relationship, Drug
Electric Stimulation
Gene Expression drug effects
Glucose metabolism
Glucose pharmacokinetics
Growth Hormone pharmacology
Hypoglycemic Agents pharmacology
In Vitro Techniques
Insulin pharmacology
Ion Channels
Isoproterenol pharmacology
Leptin pharmacology
Male
Multienzyme Complexes metabolism
Muscle Contraction drug effects
Muscle, Skeletal drug effects
Protein Serine-Threonine Kinases metabolism
Proteins genetics
RNA, Messenger metabolism
Rats
Rats, Wistar
Ribonucleotides pharmacology
Triiodothyronine pharmacology
Uncoupling Protein 2
Uncoupling Protein 3
Aminoimidazole Carboxamide analogs & derivatives
Carrier Proteins metabolism
Insulin metabolism
Membrane Transport Proteins
Mitochondrial Proteins
Muscle Contraction physiology
Muscle, Skeletal metabolism
Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-291X
- Volume :
- 283
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Biochemical and biophysical research communications
- Publication Type :
- Academic Journal
- Accession number :
- 11322761
- Full Text :
- https://doi.org/10.1006/bbrc.2001.4736