Non-invasive quantification of brain glycogen absolute concentration.

Détails

ID Serval
serval:BIB_8231B7AB6C08
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Non-invasive quantification of brain glycogen absolute concentration.
Périodique
Journal of Neurochemistry
Auteur(s)
Morgenthaler F.D., van Heeswijk R.B., Xin L., Laus S., Frenkel H., Lei H., Gruetter R.
ISSN
1471-4159 (Electronic)
ISSN-L
0022-3042
Statut éditorial
Publié
Date de publication
2008
Volume
107
Numéro
5
Pages
1414-1423
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Résumé
The only currently available method to measure brain glycogen in vivo is 13C NMR spectroscopy. Incorporation of 13C-labeled glucose (Glc) is necessary to allow glycogen measurement, but might be affected by turnover changes. Our aim was to measure glycogen absolute concentration in the rat brain by eliminating label turnover as variable. The approach is based on establishing an increased, constant 13C isotopic enrichment (IE). 13C-Glc infusion is then performed at the IE of brain glycogen. As glycogen IE cannot be assessed in vivo, we validated that it can be inferred from that of N-acetyl-aspartate IE in vivo: After [1-13C]-Glc ingestion, glycogen IE was 2.2 +/- 0.1 fold that of N-acetyl-aspartate (n = 11, R(2) = 0.77). After subsequent Glc infusion, glycogen IE equaled brain Glc IE (n = 6, paired t-test, p = 0.37), implying isotopic steady-state achievement and complete turnover of the glycogen molecule. Glycogen concentration measured in vivo by 13C NMR (mean +/- SD: 5.8 +/- 0.7 micromol/g) was in excellent agreement with that in vitro (6.4 +/- 0.6 micromol/g, n = 5). When insulin was administered, the stability of glycogen concentration was analogous to previous biochemical measurements implying that glycogen turnover is activated by insulin. We conclude that the entire glycogen molecule is turned over and that insulin activates glycogen turnover.
Mots-clé
Animals, Aspartic Acid/analogs & derivatives, Aspartic Acid/metabolism, Brain/metabolism, Brain Chemistry, Glycogen/metabolism, Magnetic Resonance Imaging/methods, Magnetic Resonance Spectroscopy/methods, Rats, Rats, Sprague-Dawley
Pubmed
Web of science
Création de la notice
04/08/2010 16:28
Dernière modification de la notice
03/03/2018 18:49
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