Tiago Brandao Rodrigues1, Pilar Lopez-Larrubia1, Sebastin Cerdn1
1LISMAR, Instituto de Investigaciones Biomdicas CSIC, Madrid, Spain
We investigated the redox dependence and compartmentation of the pyruvate pool in the brain of partially deuterated rats bearing C6 gliomas. The rats were infused with [1-13C]glucose and [2-13C]pyruvate or [U-13C3]lactate. The relative amounts of [3-13C]lactate derived from glucose to the [2-13C] or [U-13C3]lactate isotopomers derived from monocarboxylates decreased in the order contralateral>ipsilateral>tumor regions, revealing a progressive reduction in glycolysis for regions containing increasing endogenous lactate concentrations. Deuterated animals bearing C6 tumors, infused with [1-13C]glucose and [2-13C]pyruvate, showed different deuterium enrichments in the methyl groups of cerebral [3-13C] and [2-13C]lactate, revealing a slow mixing of the [3-13C] and [2-13C]pyruvate precursors in the 2H exchange timescale of their methyl groups.