Glycolysis versus TCA cycle in the primate brain as measured by combining 18F-FDG PET and 13C-NMR.
The glycolytic flux (cerebral metabolic rate of glucose CMRglc) and the TCA cycle flux (VTCA) were measured in the same monkeys by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and 13C NMR spectroscopy, respectively. Registration of nuclear magnetic resonance (NMR) and PET data were used for comparison of CMRglc and VTCA in the exact same area of the brain. Both fluxes were in good agreement with literature values (CMRglc=0.23+/-0.03 micromol/g min, VTCA=0.53+/-0.13 micromol/g min). The resulting [CMRglc/VTCA] 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 VTCA is in agreement with a metabolic coupling between the TCA cycle and glycolysis under normal physiologic conditions.
Boumezbeur
Fawzi
F
Commissariat à l'Energie Atomique, Service Hospitalier Frédéric Joliot, Orsay, France.
Besret
Laurent
L
Valette
Julien
J
Gregoire
Marie-Claude
MC
Delzescaux
Thierry
T
Maroy
Renaud
R
Vaufrey
Françoise
F
Gervais
Philippe
P
Hantraye
Philippe
P
Bloch
Gilles
G
Lebon
Vincent
V
D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D002952:Citric Acid Cycle / Q000502:physiology*; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage* / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis / Q000502:physiology*; D008251:Macaca; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods; D011859:Radiography; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000378:metabolism
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose