Linked Life Data

11015466

Source:http://linkedlifedata.com/resource/pubmed/id/11015466

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2000-10-25
pubmed:abstractText
The objectives of the present study were twofold: 1) to determine whether leucine is unique among the branched-chain amino acids (BCAA) in its ability to stimulate protein synthesis in skeletal muscle of food-deprived rats; and 2) to investigate whether changes in muscle protein synthesis after leucine administration involve a signaling pathway that includes the protein kinase mammalian target of rapamycin (mTOR). In the first set of experiments, food-deprived (18 h) male rats (200 g) were orally administered saline or 270 mg valine, isoleucine or leucine. In the second set of experiments, food-deprived rats were injected intravenously with rapamycin (0.75 mg/kg), a specific inhibitor of mTOR, before leucine administration. Only leucine stimulated protein synthesis in skeletal muscle above saline-treated controls (P: < 0.05). Furthermore, leucine was most effective among the BCAA at enhancing phosphorylation of eukaryotic initiation factor (eIF), 4E binding protein 1 (4E-BP1) and the 70-kDa ribosomal protein S6 kinase (S6K1). Leucine-dependent hyperphosphorylation of 4E-BP1 increased the availability of eIF4E to form the active eIF4G.eIF4E complex. To a lesser extent, isoleucine also enhanced phosphorylation of 4E-BP1 and S6K1. Rapamycin inhibited protein synthesis in both leucine-treated and food-deprived rats. Additionally, rapamycin prevented the stimulatory effects of leucine on eIF4E availability for binding eIF4G and inhibited leucine-dependent phosphorylation of S6K1. The data demonstrate that leucine is unique among the BCAA in its ability to stimulate protein synthesis in muscle of food-deprived rats. We show for the first time that leucine-dependent stimulation of translation initiation in vivo occurs via a rapamycin-sensitive pathway.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-3166
pubmed:author
pubmed:issnType
Print
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2413-9
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:11015466-Animals, pubmed-meshheading:11015466-Carrier Proteins, pubmed-meshheading:11015466-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:11015466-Eukaryotic Initiation Factor-4E, pubmed-meshheading:11015466-Food, pubmed-meshheading:11015466-Food Deprivation, pubmed-meshheading:11015466-Isoleucine, pubmed-meshheading:11015466-Leucine, pubmed-meshheading:11015466-Male, pubmed-meshheading:11015466-Muscle, Skeletal, pubmed-meshheading:11015466-Muscle Proteins, pubmed-meshheading:11015466-Peptide Initiation Factors, pubmed-meshheading:11015466-Phosphoproteins, pubmed-meshheading:11015466-Phosphorylation, pubmed-meshheading:11015466-Protein Biosynthesis, pubmed-meshheading:11015466-Rats, pubmed-meshheading:11015466-Rats, Sprague-Dawley, pubmed-meshheading:11015466-Ribosomal Protein S6 Kinases, pubmed-meshheading:11015466-Sirolimus, pubmed-meshheading:11015466-Valine
pubmed:year
2000
pubmed:articleTitle
Leucine stimulates translation initiation in skeletal muscle of postabsorptive rats via a rapamycin-sensitive pathway.
pubmed:affiliation
Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.