Abstract
Endurance exercise induces mitochondrial biogenesis in skeletal muscle. It has been shown that lipin-1 acts as a transcriptional coactivator in liver, and stimulates gene expression of mitochondrial enzymes. We hypothesized that lipin-1 might be involved in exercise-induced mitochondrial biogenesis in skeletal muscle. The present investigation first demonstrated that lipin-1 mRNA in rat triceps muscle was increased by approximately 2-fold after an acute bout of endurance swimming exercise. Second, ectopic expression of lipin-1 in L6 myotube increased carnitine palmitoyltransferase-1 and delta-aminolevulinate synthase gene expression. Finally, lipin-1 mRNA expression in rat triceps muscle was significantly elevated at 6h after subcutaneous injections of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) or clenbuterol, which are 5'-AMP-activated protein kinase (AMPK) and beta2-adrenergic receptor (beta2-AR) activators, respectively. These results may suggest that enhanced expression of lipin-1 is involved in exercise-induced mitochondrial enzyme adaptations, possibly through AMPK- and beta2-AR-related mechanisms.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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5-Aminolevulinate Synthetase / genetics
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AMP-Activated Protein Kinase Kinases
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Adrenergic beta-3 Receptor Agonists
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Aminoimidazole Carboxamide / analogs & derivatives
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Aminoimidazole Carboxamide / pharmacology
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Animals
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Carnitine O-Palmitoyltransferase / genetics
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Clenbuterol / pharmacology
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Epinephrine / blood
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Gene Expression
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Male
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Mitochondria, Muscle / enzymology*
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Muscle Fibers, Skeletal / metabolism
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Muscle Fibers, Skeletal / ultrastructure
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Muscle, Skeletal / drug effects
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Muscle, Skeletal / enzymology*
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Muscle, Skeletal / ultrastructure
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Norepinephrine / blood
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Nuclear Proteins / genetics
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Nuclear Proteins / physiology*
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Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
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Physical Conditioning, Animal
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Physical Endurance* / genetics
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Protein Kinases / metabolism
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RNA, Messenger / metabolism
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RNA-Binding Proteins / biosynthesis
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Rats
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Rats, Sprague-Dawley
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Ribonucleotides / pharmacology
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Swimming
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Transcription Factors / biosynthesis
Substances
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Adrenergic beta-3 Receptor Agonists
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Lpin1 protein, rat
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Nuclear Proteins
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Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
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Ppargc1a protein, rat
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RNA, Messenger
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RNA-Binding Proteins
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Ribonucleotides
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Transcription Factors
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Aminoimidazole Carboxamide
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Carnitine O-Palmitoyltransferase
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5-Aminolevulinate Synthetase
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Protein Kinases
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AMP-Activated Protein Kinase Kinases
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AICA ribonucleotide
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Norepinephrine
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Clenbuterol
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Epinephrine