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Oxidation of acetate in rabbit skeletal muscle: Detection by 13 C NMR spectroscopy in vivo
Author(s) -
Szczepaniak Lidia,
Babcock Evelyn E.,
Malloy Craig R.,
Sherry A. Dean
Publication year - 1996
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910360318
Subject(s) - skeletal muscle , in vivo , citric acid cycle , chemistry , flux (metallurgy) , nuclear magnetic resonance spectroscopy , glutamate receptor , metabolism , biochemistry , biology , anatomy , stereochemistry , receptor , microbiology and biotechnology , organic chemistry
The results of a proton‐decoupled and Overhauser‐enhanced 13 C NMR study of acetate metabolism in skeletal muscle are reported. [2‐ 13 C]Acetate was infused intravenously over 2 h into anesthetized rabbits, and skeletal muscle in the lateral thigh was monitored by 13 C NMR spectroscopy at 4.7 T. Stable 13 C enrichment in carbons 2, 3, and 4 of glutamate was observed at the end of the infusion, and the half‐time for enrichment was 17 min for glutamate C4 and 50 min for glutamate C2 and C3. The contribution of exogenous acetate to acetyl‐coenzyme A was nearly equal in skeletal muscle and heart in vivo (83–87%, measured in tissue extracts), comparable with earlier perfused heart studies in which acetate was the sole available substrate. Although relative flux through the combined anaplerotic pathways (relative to citric acid cycle flux) was higher in quiescent skeletal muscle (26%) compared with hearts (3%) from the same animals, actual anaplerotic flux was estimated to be substantially higher in heart than in skeletal muscle after correcting for differences in citric acid cycle flux in the two tissues.