| Leucine supplementation of a low-protein meal increases skeletal muscle and visceral tissue protein synthesis in neonatal pigs by stimulating mTOR-dependent translation initiation. | |
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MedLine Citation:
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PMID: 20962152 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Protein synthesis and eukaryotic initiation factor (eIF) activation are increased in skeletal muscle of neonatal pigs parenterally infused with amino acids. Leucine appears to be the most effective single amino acid to trigger these effects. To examine the response to enteral leucine supplementation, overnight food-deprived 5-d-old pigs were gavage fed at 0 and 60 min a: 1) low-protein diet (LP); 2) LP supplemented with leucine (LP+L) to equal leucine in the high-protein diet (HP); or 3) HP diet. Diets were isocaloric and equal in lactose. Fractional protein synthesis rates and translation initiation control mechanisms were examined in skeletal muscles and visceral tissues 90 min after feeding. Protein synthesis rates in longissimus dorsi, gastrocnemius, and masseter muscles, heart, jejunum, kidney, and pancreas, but not liver, were greater in the LP+L group compared with the LP group and did not differ from the HP group. Feeding LP+L and HP diets compared with the LP diet increased phosphorylation of mammalian target of rapamycin (mTOR), 4E-binding protein 1, ribosomal protein S6 kinase-1, and eIF4G and formation of the active eIF4E·eIF4G complex in longissimus dorsi muscle. In all tissues except liver, activation of mTOR effectors increased in pigs fed LP+L and HP vs. LP diets. Our results suggest that leucine supplementation of a low-protein meal stimulates protein synthesis in muscle and most visceral tissues to a rate similar to that achieved by feeding a high-protein meal and this stimulation involves activation of mTOR downstream effectors. |
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Authors:
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Roberto Murgas Torrazza; Agus Suryawan; Maria C Gazzaneo; Renán A Orellana; Jason W Frank; Hanh V Nguyen; Marta L Fiorotto; Samer El-Kadi; Teresa A Davis |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2010-10-20 |
Journal Detail:
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Title: The Journal of nutrition Volume: 140 ISSN: 1541-6100 ISO Abbreviation: J. Nutr. Publication Date: 2010 Dec |
Date Detail:
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Created Date: 2010-11-24 Completed Date: 2010-12-30 Revised Date: 2011-12-21 |
Medline Journal Info:
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Nlm Unique ID: 0404243 Medline TA: J Nutr Country: United States |
Other Details:
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Languages: eng Pagination: 2145-52 Citation Subset: IM |
Affiliation:
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USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acids
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blood Animals Animals, Newborn Blood Glucose / analysis Blotting, Western Dietary Proteins / administration & dosage* Electrophoresis, Polyacrylamide Gel Female Insulin / blood Leucine / administration & dosage* Muscle Proteins / biosynthesis* Muscle, Skeletal / metabolism* Pregnancy Protein Biosynthesis / physiology* Swine TOR Serine-Threonine Kinases / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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K08 AR051563/AR/NIAMS NIH HHS; R01 AR44474/AR/NIAMS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Amino Acids; 0/Blood Glucose; 0/Dietary Proteins; 0/Insulin; 0/Muscle Proteins; 61-90-5/Leucine; EC 2.7.1.1/TOR Serine-Threonine Kinases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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