These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effects of perfusate leucine concentration on the metabolism of valine by the isolated rat hindquarter.
    Author: Zapalowski C, Miller RH, Dixon JL, Harper AE.
    Journal: Metabolism; 1984 Oct; 33(10):922-7. PubMed ID: 6482735.
    Abstract:
    Rates of oxidation of valine and release of alpha-ketoisovaleric acid by hindquarters from rats fed a 9% casein diet were measured at intervals over 90 minutes. The hindquarters were perfused with medium containing between 0.03 and 10 mmol/L L-leucine; concentrations of valine and isoleucine were kept constant at 0.2 and 0.1 mmol/L, respectively. The rate of oxidation of [1-14C]valine increased two to threefold when the perfusate contained 0.8 or 1.0 mmol/L leucine but was depressed by 50% when the leucine concentration was 10 mmol/L. The rate of release of alpha-ketoisovaleric acid from the hindquarter was affected little by perfusate leucine concentrations up to 1.0 mmol/L, but release was depressed when perfusate leucine concentration was increased to 10 mmol/L. The rate of release of alpha-ketoisocaproic acid increased with increasing perfusate leucine concentration, as did intracellular alpha-ketoisocaproic acid and leucine concentrations. These results indicate that valine oxidation by the isolated perfused hindquarter is stimulated by a high perfusate leucine concentration (1.0 mmol/L), suggesting that this response contributes to the depressed plasma and tissue valine pools of rats fed a high-leucine diet. An excessively high concentration of leucine (10 mmol/L) suppresses valine oxidation, presumably by competing with valine for transmination or transport.
    [Abstract] [Full Text] [Related] [New Search]