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: Reduction of large neutral amino acid levels in plasma and brain of hyperleucinemic rats.
    Author: Araújo P, Wassermann GF, Tallini K, Furlanetto V, Vargas CR, Wannmacher CM, Dutra-Filho CS, Wyse AT, Wajner M.
    Journal: Neurochem Int; 2001 May; 38(6):529-37. PubMed ID: 11248401.
    Abstract:
    Neurological dysfunction is common in patients with maple syrup urine disease (MSUD). However, the mechanisms underlying the neuropathology of this disorder are poorly known. In the present study we investigated the effect of acute hyperleucinemia on plasma and brain concentrations of amino acids. Fifteen-day-old rats were injected subcutaneously with 6 micromol L-leucine per gram body weight. Controls received saline in the same volumes. The animals were sacrificed 30--120 min after injection, blood was collected and their brain rapidly removed and homogenized. The amino acid concentrations were determined by HPLC using orthophtaldialdehyde for derivatization and fluorescence for detection. The results showed significant reductions of the large neutral amino acids (LNAA) L-phenylalanine, L-tyrosine, L-isoleucine, L-valine and L-methionine, as well as L-alanine, L-serine and L-histidine in plasma and of L-phenylalanine, L-isoleucine, L-valine and L-methionine in brain, as compared to controls. In vitro experiments using brain slices to study the influence of leucine on amino acid transport and protein synthesis were also carried out. L-Leucine strongly inhibited [14C]-L-phenylalanine transport into brain, as well as the incorporation of the [14C]-amino acid mixture, [14C]-L-phenylalanine and [14C]-L-lysine into the brain proteins. Although additional studies are necessary to evaluate the importance of these effects for MSUD, considering previous findings of reduced levels of LNAA in plasma and CSF of MSUD patients during crises, it may be speculated that a decrease of essential amino acids in brain may lead to reduction of protein and neurotransmiter synthesis in this disorder.
    [Abstract] [Full Text] [Related] [New Search]