Linked Life Data

9479041

Source:http://linkedlifedata.com/resource/pubmed/id/9479041

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1998-4-30
pubmed:abstractText
System-N transport plays an important role in l-glutamine uptake into isolated rat choroid plexus but its role in the transport of another System-N substrate, l-histidine, has yet to be determined. Similarly, the possible effects on System-N mediated l-histidine transport of changes in pH and extracellular l-glutamine, such as occur in cerebral ischemia and hepatic encephalopathy, have yet to be examined. In the absence of competing amino acids, l-[3H]histidine uptake in isolated rat choroid plexus was mediated by both Na+-independent and Na+-dependent transport. The former was inhibited by 2-amino-2-norbornane carboxlic acid, indicating System-L transport, while the latter appears System-N mediated as it was inhibited by three System-N substrates but not substrates for System-A and -ASC. The Na+-dependent uptake had a Km of 0.2 mM and a Vmax of 1.4 nmol/mg/min. It accounted for 30% of l-histidine uptake in the presence of physiological concentrations of amino acids. Reductions in pH markedly inhibited Na+-dependent but not Na+-independent transport indicating that, as in liver but not neurons, System-N mediated transport at the choroid plexus is pH sensitive. Increases in l-glutamine concentration in the pathophysiological range reduced l-histidine uptake via both System-L and -N.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
783
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
37-43
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Choroid plexus histidine transport.
pubmed:affiliation
Department of Surgery (Neurosurgery), University of Michigan, R5605 Kresge I, Ann Arbor, Michigan, MI 48109-0532, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.