Effect of acute hypoglycemia on human cerebral glucose metabolism measured by (1)(3)C magnetic resonance spectroscopy
Publication year
2011Source
Diabetes, 60, 5, (2011), pp. 1467-73ISSN
Publication type
Article / Letter to editor
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Organization
Internal Medicine
Radiology
Paediatrics - OUD tm 2017
Journal title
Diabetes
Volume
vol. 60
Issue
iss. 5
Page start
p. 1467
Page end
p. 73
Subject
IGMD 1: Functional imaging; ONCOL 3: Translational research NCMLS 4: Energy and redox metabolism; Medical Imaging - Radboud University Medical CenterAbstract
OBJECTIVE: To investigate the effect of acute insulin-induced hypoglycemia on cerebral glucose metabolism in healthy humans, measured by (13)C magnetic resonance spectroscopy (MRS). RESEARCH DESIGN AND METHODS: Hyperinsulinemic glucose clamps were performed at plasma glucose levels of 5 mmol/L (euglycemia) or 3 mmol/L (hypoglycemia) in random order in eight healthy subjects (four women) on two occasions, separated by at least 3 weeks. Enriched [1-(13)C]glucose 20% w/w was used for the clamps to maintain stable plasma glucose labeling. The levels of the (13)C-labeled glucose metabolites glutamate C4 and C3 were measured over time in the occipital cortex during the clamp by continuous (13)C MRS in a 3T magnetic resonance scanner. Time courses of glutamate C4 and C3 labeling were fitted using a one-compartment model to calculate metabolic rates in the brain. RESULTS: Plasma glucose (13)C isotopic enrichment was stable at 35.1 +/- 1.8% during euglycemia and at 30.2 +/- 5.5% during hypoglycemia. Hypoglycemia stimulated release of counterregulatory hormones (all P < 0.05) and tended to increase plasma lactate levels (P = 0.07). After correction for the ambient (13)C enrichment values, label incorporation into glucose metabolites was virtually identical under both glycemic conditions. Calculated tricarboxylic acid cycle rates (V(TCA)) were 0.48 +/- 0.03 mumol/g/min during euglycemia and 0.43 +/- 0.08 mumol/g/min during hypoglycemia (P = 0.42). CONCLUSIONS: These results indicate that acute moderate hypoglycemia does not affect fluxes through the main pathways of glucose metabolism in the brain of healthy nondiabetic subjects.
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- Academic publications [245263]
- Faculty of Medical Sciences [93208]
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