Skip to main content
. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: Neurobiol Aging. 2015 Mar 25;36(7):2296–2303. doi: 10.1016/j.neurobiolaging.2015.03.012

Fig. 4.

Fig. 4

Proposed metabolic and hemodynamic changes induced by caloric restriction (CR). This figure shows the comparison between old control and CR rats. CR downregulated glucose metabolic pathway (with reduced glucose uptake, glycolysis, lactate, and glucose-glycogen recycling) but upregulated ketogenic pathway. The ketone bodies may come from astrocytic fatty acid oxidation or blood stream. Ketone bodies are converted to acetoacetate and then further metabolized to acetyl-CoA. The altered metabolic pathway resulted in enhanced TCA cycle flux and glutamate-glutamine recycling (Vcyc(tot)) between neurons and astrocytes. Elevated CBF may be due to enhanced neuronal activity and increased ketone bodies levels. *This was shown in our previous study (Lin et al., 2014). Abbreviations: BHB, β-hydroxybutyrate; CBF, cerebral blood flow; TCA, tricarboxylic acid.