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Brain energy metabolism measured by (13)C magnetic resonance spectroscopy in vivo upon infusion of [3-(13)C]lactate

Duarte, João M N LU ; Girault, Freya-Merret and Gruetter, Rolf (2015) In Journal of Neuroscience Research 93(7). p.18-1009
Abstract

The brain uses lactate produced by glycolysis as an energy source. How lactate originated from the blood stream is used to fuel brain metabolism is not clear. The current study measures brain metabolic fluxes and estimates the amount of pyruvate that becomes labeled in glial and neuronal compartments upon infusion of [3-(13)C]lactate. For that, labeling incorporation into carbons of glutamate and glutamine was measured by (13)C magnetic resonance spectroscopy at 14.1 T and analyzed with a two-compartment model of brain metabolism to estimate rates of mitochondrial oxidation, glial pyruvate carboxylation, and the glutamate-glutamine cycle as well as pyruvate fractional enrichments. Extracerebral lactate at supraphysiological levels... (More)

The brain uses lactate produced by glycolysis as an energy source. How lactate originated from the blood stream is used to fuel brain metabolism is not clear. The current study measures brain metabolic fluxes and estimates the amount of pyruvate that becomes labeled in glial and neuronal compartments upon infusion of [3-(13)C]lactate. For that, labeling incorporation into carbons of glutamate and glutamine was measured by (13)C magnetic resonance spectroscopy at 14.1 T and analyzed with a two-compartment model of brain metabolism to estimate rates of mitochondrial oxidation, glial pyruvate carboxylation, and the glutamate-glutamine cycle as well as pyruvate fractional enrichments. Extracerebral lactate at supraphysiological levels contributes at least two-fold more to replenish the neuronal than the glial pyruvate pools. The rates of mitochondrial oxidation in neurons and glia, pyruvate carboxylase, and glutamate-glutamine cycles were similar to those estimated by administration of (13)C-enriched glucose, the main fuel of brain energy metabolism. These results are in agreement with primary utilization of exogenous lactate in neurons rather than astrocytes.

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Contribution to journal
publication status
published
keywords
Animals, Blood Gas Analysis, Brain, Carbon Isotopes, Energy Metabolism, Glutamic Acid, Glutamine, Hydrogen-Ion Concentration, Lactic Acid, Magnetic Resonance Spectroscopy, Male, Radionuclide Imaging, Rats, Rats, Sprague-Dawley, Journal Article, Research Support, Non-U.S. Gov't
in
Journal of Neuroscience Research
volume
93
issue
7
pages
10 pages
publisher
John Wiley & Sons
external identifiers
  • scopus:84929654459
ISSN
1097-4547
DOI
10.1002/jnr.23531
language
English
LU publication?
no
id
309049b0-3680-4add-9086-377189865f2d
date added to LUP
2017-10-19 15:18:27
date last changed
2017-10-24 10:30:50
@article{309049b0-3680-4add-9086-377189865f2d,
  abstract     = {<p>The brain uses lactate produced by glycolysis as an energy source. How lactate originated from the blood stream is used to fuel brain metabolism is not clear. The current study measures brain metabolic fluxes and estimates the amount of pyruvate that becomes labeled in glial and neuronal compartments upon infusion of [3-(13)C]lactate. For that, labeling incorporation into carbons of glutamate and glutamine was measured by (13)C magnetic resonance spectroscopy at 14.1 T and analyzed with a two-compartment model of brain metabolism to estimate rates of mitochondrial oxidation, glial pyruvate carboxylation, and the glutamate-glutamine cycle as well as pyruvate fractional enrichments. Extracerebral lactate at supraphysiological levels contributes at least two-fold more to replenish the neuronal than the glial pyruvate pools. The rates of mitochondrial oxidation in neurons and glia, pyruvate carboxylase, and glutamate-glutamine cycles were similar to those estimated by administration of (13)C-enriched glucose, the main fuel of brain energy metabolism. These results are in agreement with primary utilization of exogenous lactate in neurons rather than astrocytes.</p>},
  author       = {Duarte, João M N and Girault, Freya-Merret and Gruetter, Rolf},
  issn         = {1097-4547},
  keyword      = {Animals,Blood Gas Analysis,Brain,Carbon Isotopes,Energy Metabolism,Glutamic Acid,Glutamine,Hydrogen-Ion Concentration,Lactic Acid,Magnetic Resonance Spectroscopy,Male,Radionuclide Imaging,Rats,Rats, Sprague-Dawley,Journal Article,Research Support, Non-U.S. Gov't},
  language     = {eng},
  number       = {7},
  pages        = {18--1009},
  publisher    = {John Wiley & Sons},
  series       = {Journal of Neuroscience Research},
  title        = {Brain energy metabolism measured by (13)C magnetic resonance spectroscopy in vivo upon infusion of [3-(13)C]lactate},
  url          = {http://dx.doi.org/10.1002/jnr.23531},
  volume       = {93},
  year         = {2015},
}