Mor Mishkovsky1,2, Arnaud Comment1,2, Rolf Gruetter1,3
1Laboratory for Functional & Metabolic Imaging , Ecole Polytechnique Fdrale de Lausanne, Lausanne, Switzerland; 2Department of Radiology, Universit de Lausanne, Lausanne, Switzerland; 3Department of Radiology, Universits de Lausanne et de Genve, Lausanne & Genve, Switzerland
Acetate brain metabolism was studied in vivo in rats following the infusion of hyperpolarized 1-13C and 13C2 sodium acetate solutions, leading to the first direct observation of the brain TCA cycle intermediate 2-oxoglutarate (2OG). The observation of 2OG and the lack of glutamate (Glu) signal imply that the reactions leading to 13C-label incorporation into Glu are operating, in the glial compartment in vivo, at a rate much lower than that of transaminase. We deduced from this observation that transport across the inner mitochondria membrane is rate limiting.