Steady-state cerebral glucose concentrations and transport in the human brain.

Détails

ID Serval
serval:BIB_FC897B49CDE9
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Steady-state cerebral glucose concentrations and transport in the human brain.
Périodique
Journal of Neurochemistry
Auteur(s)
Gruetter R., Ugurbil K., Seaquist E.R.
ISSN
0022-3042 (Print)
ISSN-L
0022-3042
Statut éditorial
Publié
Date de publication
1998
Volume
70
Numéro
1
Pages
397-408
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.Publication Status: ppublish
Résumé
Understanding the mechanism of brain glucose transport across the blood-brain barrier is of importance to understanding brain energy metabolism. The specific kinetics of glucose transport have been generally described using standard Michaelis-Menten kinetics. These models predict that the steady-state glucose concentration approaches an upper limit in the human brain when the plasma glucose level is well above the Michaelis-Menten constant for half-maximal transport, Kt. In experiments where steady-state plasma glucose content was varied from 4 to 30 mM, the brain glucose level was a linear function of plasma glucose concentration. At plasma concentrations nearing 30 mM, the brain glucose level approached 9 mM, which was significantly higher than predicted from the previously reported Kt of approximately 4 mM (p < 0.05). The high brain glucose concentration measured in the human brain suggests that ablumenal brain glucose may compete with lumenal glucose for transport. We developed a model based on a reversible Michaelis-Menten kinetic formulation of unidirectional transport rates. Fitting this model to brain glucose level as a function of plasma glucose level gave a substantially lower Kt of 0.6 +/- 2.0 mM, which was consistent with the previously reported millimolar Km of GLUT-1 in erythrocyte model systems. Previously reported and reanalyzed quantification provided consistent kinetic parameters. We conclude that cerebral glucose transport is most consistently described when using reversible Michaelis-Menten kinetics.
Mots-clé
Adult, Biological Transport/physiology, Brain/anatomy & histology, Brain/metabolism, Glucose/metabolism, Homeostasis/physiology, Humans, Kinetics, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Middle Aged, Models, Biological, Osmolar Concentration
Pubmed
Web of science
Création de la notice
04/08/2010 16:28
Dernière modification de la notice
20/08/2019 17:27
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