Glycolysis versus TCA Cycle in the Primate Brain as Measured by Combining 18 F-FDG PET and 13 C-NMR

• Published in: Journal of cerebral blood flow and metabolism 2005-11, Vol.25 (11), p.1418-1423
• Main Authors: Boumezbeur, Fawzi, Besret, Laurent, Valette, Julien, Gregoire, Marie-Claude, Delzescaux, Thierry, Maroy, Renaud, Vaufrey, Françoise, Gervais, Philippe, Hantraye, Philippe, Bloch, Gilles, Lebon, Vincent
• Format: Article
• Language: English
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1038/sj.jcbfm.9600145

The glycolytic flux (cerebral metabolic rate of glucose CMRglc) and the TCA cycle flux ( V TCA ) were measured in the same monkeys by 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography (PET) and 13 C NMR spectroscopy, respectively. Registration of nuclear magnetic resonance (NMR) and PET data were used for comparison of CMRglc and V TCA in the exact same area of the brain. Both fluxes were in good agreement with literature values (CMR glc 0.23 ± 0.03 μmol/g min, V TCA = 0.53 ± 0.13 μmol/gmin). The resulting [ CMRglc/V TCA ] ratio was 0.46 ± 0.12 ( n = 5, mean ± s.d.), not significantly different from the 0.5 expected when glucose is the sole fuel that is completely oxidized. Our results provide a cross-validation of both techniques. Comparison of CMRglc with V TCA is in agreement with a metabolic coupling between the TCA cycle and glycolysis under normal physiologic conditions.