Application of dynamic metabolomics to examine in vivo skeletal muscle glucose metabolism in the chronically high-fat fed mouse.
BACKGROUND
Defects in muscle glucose metabolism are linked to type 2 diabetes. Mechanistic studies examining these defects rely on the use of high fat-fed rodent models and typically involve the determination of muscle glucose uptake under insulin-stimulated conditions. While insightful, they do not necessarily reflect the physiology of the postprandial state. In addition, most studies do not examine aspects of glucose metabolism beyond the uptake process. Here we present an approach to study rodent muscle glucose and intermediary metabolism under the dynamic and physiologically relevant setting of the oral glucose tolerance test (OGTT).


RESULTS
In vivo muscle glucose and intermediary metabolism was investigated following oral administration of [U-(13)C] glucose. Quadriceps muscles were collected 15 and 60 min after glucose administration and metabolite flux profiling was determined by measuring (13)C mass isotopomers in glycolytic and tricarboxylic acid (TCA) cycle intermediates via gas chromatography-mass spectrometry. While no dietary effects were noted in the glycolytic pathway, muscle from mice fed a high fat diet (HFD) exhibited a reduction in labelling in TCA intermediates. Interestingly, this appeared to be independent of alterations in flux through pyruvate dehydrogenase. In addition, our findings suggest that TCA cycle anaplerosis is negligible in muscle during an OGTT.


CONCLUSIONS
Under the dynamic physiologically relevant conditions of the OGTT, skeletal muscle from HFD fed mice exhibits alterations in glucose metabolism at the level of the TCA cycle.
Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125, Australia. Electronic address: greg.kowalski@deakin.edu.au.
Greg M
GM
Kowalski
Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia.
David P
DP
De Souza
Brigham and Women's Hospital, Department of Medicine, Boston, MA, USA.
Micah L
ML
Burch
Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125, Australia.
Steven
S
Hamley
Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia.
Joachim
J
Kloehn
Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125, Australia.
Ahrathy
A
Selathurai
Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia.
Dedreia
D
Tull
Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia.
Sean
S
O'Callaghan
Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria 3010, Australia.
Malcolm J
MJ
McConville
Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria 3125, Australia.
Clinton R
CR
Bruce
D000818:Animals; D002952:Citric Acid Cycle; D059305:Diet, High-Fat; D008401:Gas Chromatography-Mass Spectrometry; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006019:Glycolysis; D008297:Male; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D013997:Time Factors
D005947:Glucose
Metabolomics; Muscle insulin resistance; Stable isotopes