Linked Life Data

7595553

Source:http://linkedlifedata.com/resource/pubmed/id/7595553

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1995-12-15
pubmed:abstractText
Despite L-glutamine being the most abundant amino acid in CSF, the mechanisms of its transport at the choroid plexus have not been fully elucidated. This study examines the role of L-, A-, ASC-, and N-system amino acid transporters in L-[14C]glutamine uptake into isolated rat choroid plexus. In the absence of competing amino acids, approximately half the glutamine uptake was via a Na(+)-dependent mechanism. The Na(+)-independent uptake was inhibited by 2-amino-2-norbornane carboxylic acid, indicating that it is probably via an L-system transporter. Na(+)-dependent uptake was inhibited neither by the A-system substrate alpha-(methylamino)isobutyric acid nor by the ASC-system substrate cysteine. It was inhibited by histidine, asparagine, and L-glutamate gamma-hydroxamate, three N-system substrates. Replacement of Na+ with Li+ had little effect on uptake, another feature of N-system amino acid transport. These data therefore indicate that N-system amino acid transport is present at the choroid plexus. The Vmax and Km for glutamine transport by this system were 8.1 +/- 0.3 nmol/mg/min and 3.3 +/- 0.4 mM, respectively. This system may play an important role in the control of CSF glutamine, particularly when the CSF glutamine level is elevated as in hepatic encephalopathy.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-3042
pubmed:author
pubmed:issnType
Print
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2571-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
N-system amino acid transport at the blood--CSF barrier.
pubmed:affiliation
Department of Surgery, University of Michigan, Ann Arbor 48109-0532, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't