Metabolism of branched-chain amino acids in starved rats: the role of hepatic tissue
Language English Country Czech Republic Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
11300224
Knihovny.cz E-resources
- MeSH
- Alanine Transaminase analysis MeSH
- Aspartate Aminotransferases analysis MeSH
- Potassium analysis MeSH
- Glucose analysis MeSH
- Starvation metabolism pathology MeSH
- Isoleucine metabolism MeSH
- Liver metabolism pathology MeSH
- Keto Acids metabolism MeSH
- Muscle, Skeletal metabolism MeSH
- Rats MeSH
- Leucine metabolism MeSH
- Oxidation-Reduction MeSH
- Rats, Wistar MeSH
- Proteins metabolism MeSH
- Protein Biosynthesis MeSH
- Sodium analysis MeSH
- Valine metabolism MeSH
- Organ Size MeSH
- Amino Acids, Branched-Chain blood metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Alanine Transaminase MeSH
- alpha-ketoisocaproic acid MeSH Browser
- Aspartate Aminotransferases MeSH
- Potassium MeSH
- Glucose MeSH
- Isoleucine MeSH
- Keto Acids MeSH
- Leucine MeSH
- Proteins MeSH
- Sodium MeSH
- Valine MeSH
- Amino Acids, Branched-Chain MeSH
Parameters of branched-chain amino acids (BCAA; leucine, isoleucine and valine) and protein metabolism were evaluated using L-[1-(14)C]leucine and alpha-keto[1-(14)C]isocaproate (KIC) in the whole body and in isolated perfused liver (IPL) of rats fed ad libitum or starved for 3 days. Starvation caused a significant increase in plasma BCAA levels and a decrease in leucine appearance from proteolysis, leucine incorporation into body proteins, leucine oxidation, leucine-oxidized fraction, and leucine clearance. Protein synthesis decreased significantly in skeletal muscle and the liver. There were no significant differences in leucine and KIC oxidation by IPL. In starved animals, a significant increase in net release of BCAA and tyrosine by IPL was observed, while the effect on other amino acids was non-significant. We conclude that the protein-sparing phase of uncomplicated starvation is associated with decreased whole-body proteolysis, protein synthesis, branched-chain amino acid (BCAA) oxidation, and BCAA clearance. The increase in plasma BCAA levels in starved animals results in part from decreased BCAA catabolism, particularly in heart and skeletal muscles, and from a net release of BCAA by the hepatic tissue.
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