Glucose uptake in brain

In the brain, when ketones are metabolized to acetyl CoA, pyruvate dehydrogenase is inhibited. Glycolysis and subsequently glucose uptake in brain decreases. This important switch spares body protein (which otherwise would be catabolized to form glucose by gluconeogenesis in the liver) by allowing the brain to indirectly metabolize fetty acids as ketone bodies. 

Effect of Insulin on Glucose Uptake in Brain, Lens, and Tumor Cells Site of Action of Insulin on Carbohydrate Metabolism Transport Theory... 

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