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J Cereb Blood Flow Metab. 2013 Aug;33(8):1307-11. doi: 10.1038/jcbfm.2013.87. Epub 2013 Jun 5.

Ketosis proportionately spares glucose utilization in brain.

Author information

1
Department of Biomedical Engineering, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4954, USA.

Abstract

The brain is dependent on glucose as a primary energy substrate, but is capable of utilizing ketones such as β-hydroxybutyrate and acetoacetate, as occurs with fasting, starvation, or chronic feeding of a ketogenic diet. The relationship between changes in cerebral metabolic rates of glucose (CMRglc) and degree or duration of ketosis remains uncertain. To investigate if CMRglc decreases with chronic ketosis, 2-[(18)F]fluoro-2-deoxy-D-glucose in combination with positron emission tomography, was applied in anesthetized young adult rats fed 3 weeks of either standard or ketogenic diets. Cerebral metabolic rates of glucose (μmol/min per 100 g) was determined in the cerebral cortex and cerebellum using Gjedde-Patlak analysis. The average CMRglc significantly decreased in the cerebral cortex (23.0±4.9 versus 32.9±4.7) and cerebellum (29.3±8.6 versus 41.2±6.4) with increased plasma ketone bodies in the ketotic rats compared with standard diet group. The reduction of CMRglc in both brain regions correlates linearly by ∼9% for each 1 mmol/L increase of total plasma ketone bodies (0.3 to 6.3 mmol/L). Together with our meta-analysis, these data revealed that the degree and duration of ketosis has a major role in determining the corresponding change in CMRglc with ketosis.

PMID:
23736643
PMCID:
PMC3734783
DOI:
10.1038/jcbfm.2013.87
[Indexed for MEDLINE]
Free PMC Article

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