Determination of cerebral glucose transport and metabolic kinetics by dynamic MR spectroscopy
| Autor: | Chrit T. W. Moonen, P. C. M. Van Zijl, Scott M. Eleff, D. Davis, J. M. Strong, R. J. Parker |
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| Rok vydání: | 1997 |
| Předmět: |
Carbon Isotopes
Magnetic Resonance Spectroscopy Physiology Chemistry Endocrinology Diabetes and Metabolism Models Neurological Dynamic mr Kinetics Glucose transporter Brain Glucose-6-Phosphate Reproducibility of Results Nuclear magnetic resonance spectroscopy Michaelis–Menten kinetics Glucose Nuclear magnetic resonance In vivo Metabolic kinetics Hyperglycemia Physiology (medical) Cats Animals Spectroscopy Tomography Emission-Computed |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 273:E1216-E1227 |
| ISSN: | 1522-1555 0193-1849 |
| DOI: | 10.1152/ajpendo.1997.273.6.e1216 |
| Popis: | A new in vivo nuclear magnetic resonance (NMR) spectroscopy method is introduced that dynamically measures cerebral utilization of magnetically labeled [1-13C]glucose from the change in total brain glucose signals on infusion. Kinetic equations are derived using a four-compartment model incorporating glucose transport and phosphorylation. Brain extract data show that the glucose 6-phosphate concentration is negligible relative to glucose, simplifying the kinetics to three compartments and allowing direct determination of the glucose-utilization half-life time [ t½= ln2/( k2+ k3)] from the time dependence of the NMR signal. Results on isofluorane ( n = 5)- and halothane ( n = 7)- anesthetized cats give a hyperglycemic t½= 5.10 ± 0.11 min−1(SE). Using Michaelis-Menten kinetics and an assumed half-saturation constant Kt= 5 ± 1 mM, we determined a maximal transport rate Tmax= 0.83 ± 0.19 μmol ⋅ g−1⋅ min−1, a cerebral metabolic rate of glucose CMRGlc= 0.22 ± 0.03 μmol ⋅ g−1⋅ min−1, and a normoglycemic cerebral influx rate CIRGlc= 0.37 ± 0.05 μmol ⋅ g−1⋅ min−1. Possible extension of this approach to positron emission tomography and proton NMR is discussed. |
| Databáze: | OpenAIRE |
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