Metabolism of [1,6-13C]glucose in the cerebellum of 18-day-old rats: Comparison with cerebral metabolism

There is little information on metabolism in developing cerebellum despite the known importance of this region in cognition and motor tasks. Ex vivo H-1- and C-13-NMR spectroscopy were used to determine metabolism during late postnatal development in cerebellum and cerebrum from 18-day-old rat pups after intraperitoneal (i.p.) injection of [1,6-C-13]glucose. The concentration of several metabolites in cerebellum was distinctly different than cerebrum; alanine, glutamine, creatine and myo-inositol were higher in cerebellum than cerebrum, the concentrations of lactate, GABA, aspartate and N-acetylaspartate (NAA) were lower in cerebellum than in cerebrum, and levels of glutamate, succinate, choline and taurine were similar in both brain regions. The incorporation of label from the metabolism of [1,6-C-13]glucose into most isotopomers of glutamate (GLU), glutamine (GLN), GABA and aspartate was lower in cerebellum than in cerebrum. Incorporation of label into the C2 position of lactate via the pyruvate recycling pathway was found in both brain regions. The ratio of newly synthesized GLN/GLU was significantly higher in cerebellum than in cerebrum indicating relatively active metabolism via glutamine synthetase in cerebellar astrocytes at postnatal day 18. This is the first study to determine metabolism in the cerebellum and cerebrum of male and female rat brain.