| Non-invasive quantification of brain glycogen absolute concentration. | |
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MedLine Citation:
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PMID: 19013831 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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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. |
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Authors:
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Florence D Morgenthaler; Ruud B van Heeswijk; Lijing Xin; Sabrina Laus; Hanne Frenkel; Hongxia Lei; Rolf Gruetter |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of neurochemistry Volume: 107 ISSN: 1471-4159 ISO Abbreviation: J. Neurochem. Publication Date: 2008 Dec |
Date Detail:
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Created Date: 2008-11-14 Completed Date: 2008-12-24 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 2985190R Medline TA: J Neurochem Country: England |
Other Details:
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Languages: eng Pagination: 1414-23 Citation Subset: IM |
Affiliation:
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Centre d'Imagerie Biomédicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. Florence.Morgenthaler@epfl.ch |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Aspartic Acid / analogs & derivatives, metabolism Brain / metabolism* Brain Chemistry* Glycogen / metabolism* Magnetic Resonance Imaging / methods Magnetic Resonance Spectroscopy / methods Rats Rats, Sprague-Dawley |
| Grant Support | |
ID/Acronym/Agency:
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R01 NS042005-06/NS/NINDS NIH HHS; R01NS042005/NS/NINDS NIH HHS |
| Chemical | |
Reg. No./Substance:
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56-84-8/Aspartic Acid; 9005-79-2/Glycogen; 997-55-7/N-acetylaspartate |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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