title: Glucose ingestion during exercise blunts exercise-induced gene expression of skeletal muscle fat oxidative genes.
abstract: Ingestion of carbohydrate during exercise may blunt the stimulation of fat oxidative pathways by raising plasma insulin and glucose concentrations and lowering plasma free fatty acid (FFA) levels, thereby causing a marked shift in substrate oxidation. We investigated the effects of a single 2-h bout of moderate-intensity exercise on the expression of key genes involved in fat and carbohydrate metabolism with or without glucose ingestion in seven healthy untrained men (22.7 +/- 0.6 yr; body mass index: 23.8 +/- 1.0 kg/m(2); maximal O(2) consumption: 3.85 +/- 0.21 l/min). Plasma FFA concentration increased during exercise (P < 0.01) in the fasted state but remained unchanged after glucose ingestion, whereas fat oxidation (indirect calorimetry) was higher in the fasted state vs. glucose feeding (P < 0.05). Except for a significant decrease in the expression of pyruvate dehydrogenase kinase-4 (P < 0.05), glucose ingestion during exercise produced minimal effects on the expression of genes involved in carbohydrate utilization. However, glucose ingestion resulted in a decrease in the expression of genes involved in fatty acid transport and oxidation (CD36, carnitine palmitoyltransferase-1, uncoupling protein 3, and 5'-AMP-activated protein kinase-alpha(2); P < 0.05). In conclusion, glucose ingestion during exercise decreases the expression of genes involved in lipid metabolism rather than increasing genes involved in carbohydrate metabolism.
authors: Dept. of Human Physiology, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
authors: Anthony E
authors: AE
authors: Civitarese
authors: Matthijs K C
authors: MK
authors: Hesselink
authors: Aaron P
authors: AP
authors: Russell
authors: Eric
authors: E
authors: Ravussin
authors: Patrick
authors: P
authors: Schrauwen
mesh_terms: D055372:AMP-Activated Protein Kinases; D000328:Adult; D001692:Biological Transport / Q000235:genetics; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D018955:CD36 Antigens / Q000235:genetics; D050260:Carbohydrate Metabolism / Q000235:genetics; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D015444:Exercise / Q000502:physiology*; D005227:Fatty Acids / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D015870:Gene Expression / Q000187:drug effects*; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D007328:Insulin / Q000097:blood; D007473:Ion Channels; D050356:Lipid Metabolism / Q000235:genetics*; D008297:Male; D024101:Mitochondrial Proteins; D009097:Multienzyme Complexes / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D000071247:Uncoupling Protein 3
chemical_list: D001786:Blood Glucose; D018955:CD36 Antigens; D002352:Carrier Proteins; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D007473:Ion Channels; D024101:Mitochondrial Proteins; D009097:Multienzyme Complexes; C000604392:UCP3 protein, human; D000071247:Uncoupling Protein 3; D002334:Carnitine O-Palmitoyltransferase; D011494:Protein Kinases; C403287:pyruvate dehydrogenase kinase 4; C526181:PRKAA2 protein, human; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D005947:Glucose