Helen J. Atherton1, Marie A. Shroeder1, Lisa C. Heather1, Julian L. Griffin2, Kieran Clarke1, George K. Radda1, Damian J. Tyler1
1Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxfordshire, UK; 2Biochemistry, University of Cambridge, Cambridge, Cambridgeshire, UK
In this study Dynamic Nuclear Polarization enhanced 13C-MRS was used to investigate the effects of elevated thyroid hormone (T3) levels on cardiac metabolism in vivo. Our study uniquely revealed that pyruvate dehydrogenase (PDH) flux was reduced by 76 % in rats administered T3 for 7 days, indicative of an increased reliance on fatty acid oxidation (FAO) for ATP production. Metabolically profiling cardiac tissue ex vivo using 1H-NMR revealed a concomitant increase in glycolysis, evidenced by increased lactate and alanine, and decreased glucose. Together these results suggest that the hyperthyroid heart can be characterized by increased FAO and glycolysis, and decreased PDH flux.
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