Vladimir Mlynarik1, Cristina Cudalbu1, Hanne Frenkel1, Nicolas Costers1,2, Rolf Gruetter1,3
1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fdrale de Lausanne, Lausanne, Switzerland; 2Katholieke Universiteit Leuven, Leuven, Belgium; 3Departments of Radiology, Universities of Lausanne and Geneva, Switzerland
Absolute metabolic maps of 12 metabolites were obtained in rat brain at different plasma glucose (Glc) concentrations (6.4 19 mmol/L) using short-echo-time proton spectroscopic imaging. A satisfactory linear fit of brain Glc concentration versus plasma Glc concentration in cortex, hippocampus and thalamus was found. The slope of this fit was the same within experimental error in all measured brain structures. The linear fit of increased lactate concentrations at increased plasma Glc levels was poor, indicating that other factors such as stress or impaired metabolism during long-term anesthesia can affect the lactate concentration in brain. Concentrations of myo-inositol, taurine, ascorbate, phosphoethanolamine, glutamine, GABA, N-acetylaspartate, total creatine, total choline and macromolecules were not substantially affected by acute hyperglycemia.