Glucose kinetics during prolonged exercise in highly trained human subjects: effect of glucose ingestion
| Autor: | Anne Raben, Anton J. M. Wagenmakers, Asker E. Jeukendrup, Annemie P. Gijsen, Jos H. C. H. Stegen, Fred Brouns, Wim H. M. Saris |
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| Přispěvatelé: | Humane Biologie, RS: NUTRIM School of Nutrition and Translational Research in Metabolism |
| Rok vydání: | 1999 |
| Předmět: |
Adult
Blood Glucose Glycerol medicine.medical_specialty Time Factors Physiology Administration Oral Glucose ingestion Fatty Acids Nonesterified chemistry.chemical_compound Metabolic clearance rate Internal medicine medicine Humans Insulin Ingestion Lactic Acid Exercise Physical Education and Training Glycogen Prolonged exercise Muscles Respiration Original Articles Carbon Dioxide Carbohydrate Lipid Metabolism Kinetics Glucose Endocrinology Gluconeogenesis chemistry Carbohydrate Metabolism Glucose kinetics Oxidation-Reduction |
| Zdroj: | Journal of Physiology, 515(Pt 2), 579-589. Wiley |
| ISSN: | 1469-7793 0022-3751 |
| Popis: | Nutrition Research Centre, Department of Human Biology, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands. A.E.Jeukendrup@bham.ac.uk1. The objectives of this study were (1) to investigate whether glucose ingestion during prolonged exercise reduces whole body muscle glycogen oxidation, (2) to determine the extent to which glucose disappearing from the plasma is oxidized during exercise with and without carbohydrate ingestion and (3) to obtain an estimate of gluconeogenesis. 2. After an overnight fast, six well-trained cyclists exercised on three occasions for 120 min on a bicycle ergometer at 50 % maximum velocity of O2 uptake and ingested either water (Fast), or a 4 % glucose solution (Lo-Glu) or a 22 % glucose solution (Hi-Glu) during exercise. 3. Dual tracer infusion of [U-13C]-glucose and [6,6-2H2]-glucose was given to measure the rate of appearance (Ra) of glucose, muscle glycogen oxidation, glucose carbon recycling, metabolic clearance rate (MCR) and non-oxidative disposal of glucose. 4. Glucose ingestion markedly increased total Ra especially with Hi-Glu. After 120 min Ra and rate of disappearance (Rd) of glucose were 51-52 micromol kg-1 min-1 during Fast, 73-74 micromol kg-1 min-1 during Lo-Glu and 117-119 micromol kg-1 min-1 during Hi-Glu. The percentage of Rd oxidized was between 96 and 100 % in all trials. 5. Glycogen oxidation during exercise was not reduced by glucose ingestion. The vast majority of glucose disappearing from the plasma is oxidized and MCR increased markedly with glucose ingestion. Glucose carbon recycling was minimal suggesting that gluconeogenesis in these conditions is negligible. |
| Databáze: | OpenAIRE |
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