Linked Life Data

9721758

Source:http://linkedlifedata.com/resource/pubmed/id/9721758

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1998-9-21
pubmed:abstractText
Metabolic compartmentation of amino acid metabolism in brain is exemplified by the differential synthesis of glutamate and glutamine from the identical precursor and by the localization of the enzyme glutamine synthetase in glial cells. In the current study, we determined if the oxidative metabolism of glutamate and glutamine was also compartmentalized. The relative oxidation rates of glutamate and glutamine in the hippocampus of free-moving rats was determined by using microdialysis both to infuse the radioactive substrate and to collect 14CO2 generated during their oxidation. At the end of the oxidation experiment, the radioactive substrate was replaced by artificial CSF, 2 min-fractions were collected, and the specific activities of glutamate and glutamine were determined. Extrapolation of the specific activity back to the time that artificial CSF replaced 14C-amino acids in the microdialysis probe yielded an approximation of the interstitial specific activity during the oxidation. The extrapolated interstitial specific activities for [14C]glutamate and [14C]glutamine were 59 +/- 18 and 2.1 +/- 0.5 dpm/pmol, respectively. The initial infused specific activities for [U-14C]glutamate and [U-14C]glutamine were 408 +/- 8 and 387 +/- 1 dpm/pmol, respectively. The dilution of glutamine was greater than that of glutamate, consistent with the difference in concentrations of these amino acids in the interstitial space. Based on the extrapolated interstitial specific activities, the rate of glutamine oxidation exceeds that of glutamate oxidation by a factor of 5.3. These data indicate compartmentation of either uptake and/or oxidative metabolism of these two amino acids. The presence of [14C]glutamine in the interstitial space when [14C]glutamate was perfused into the brain provided further evidence for the glutamate/glutamine cycle in brain.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-3042
pubmed:author
pubmed:issnType
Print
pubmed:volume
71
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1315-20
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Compartmentation of [14C]glutamate and [14C]glutamine oxidative metabolism in the rat hippocampus as determined by microdialysis.
pubmed:affiliation
Department of Pediatrics, University of Maryland, Baltimore 21201-1559, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.