Glucose ingestion during exercise blunts exercise-induced gene expression of skeletal muscle fat oxidative genes.
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.
Civitarese
Anthony E
AE
Dept. of Human Physiology, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
Hesselink
Matthijs K C
MK
Russell
Aaron P
AP
Ravussin
Eric
E
Schrauwen
Patrick
P
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
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