Four weeks one-leg training and high fat diet does not alter PPARalpha protein or mRNA expression in human skeletal muscle.
Fatty acid metabolism is influenced by training and diet with exercise training mediating this through activation of nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha) in skeletal muscle. This study investigated the effect of training and high fat or normal diet on PPARalpha expression in human skeletal muscle. Thirteen men trained one leg (T) four weeks (31.5 h in total), while the other leg (UT) served as control. During the 4 weeks six subjects consumed high fat (FAT) diet and seven subjects maintained a normal (CHO) diet. Biopsies were obtained from vastus lateralis muscle in both legs before and after training. After the biopsy, one-leg extension exercise was performed in random order with both legs 30 min at 95% of workload max. A training effect was evident as citrate synthase activity increased (P < 0.05) by 15% in the trained, but not the control leg in both groups. During exercise respiratory exchange ratio was lower in FAT (0.86 +/- 0.01, 0.83 +/- 0.01, mean +/- SEM) than CHO (0.96 +/- 0.02, 0.94 +/- 0.03) and in UT than T legs, respectively. The PPARalpha protein (144 +/- 44, 104 +/- 28, 79 +/- 15, 79 +/- 14, % of pre level) and PPARalpha mRNA (69 +/- [2, 2], 78 +/- [7, 6], 92 +/- [22, 18], 106 +/- [21, 18], % of pre level, geometric mean +/- SEM) expression remained unchanged by diet and training in FAT (UT, T) and CHO (UT, T), respectively. After the training and diet CS, HAD, PPARalpha, UCP2, UCP3 and mFABP mRNA content remained unchanged, whereas GLUT4 mRNA was lower in both groups and LDHA mRNA was lower (P < 0.05) only in FAT.


CONCLUSIONS
4 weeks one leg knee extensor training did not affect PPARalpha protein or mRNA expression. Furthermore, higher fat oxidation during exercise after fat rich diet was not accompanied by an increased PPARalpha protein or mRNA expression after 4 weeks.
Helge
J W
JW
Copenhagen Muscle Research Centre, Department Medical Physiology, Panum Institute building 12, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark. jhelge@mfi.ku.dk
Bentley
D
D
Schjerling
P
P
Willer
M
M
Gibala
M J
MJ
Franch
J
J
Tapia-Laliena
M A
MA
Daugaard
J R
JR
Andersen
J L
JL
D015094:3-Hydroxyacyl CoA Dehydrogenases; D001707:Biopsy, Needle; D002950:Citrate (si)-Synthase; D004032:Diet; D004041:Dietary Fats / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology; D016552:Ergometry; D015444:Exercise / Q000502:physiology*; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins; D005786:Gene Expression Regulation; D051275:Glucose Transporter Type 4; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D006801:Humans; D007473:Ion Channels; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D000080864:Lactate Dehydrogenase 5; D007866:Leg / Q000502:physiology; D008066:Lipolysis / Q000502:physiology; D008297:Male; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000378:metabolism*; D009218:Myosins / Q000032:analysis; D047493:PPAR alpha / Q000096:biosynthesis*; D030481:Pyruvate Dehydrogenase (Lipoamide); D011897:Random Allocation; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
D004041:Dietary Fats; C493408:FABP3 protein, human; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins; D051275:Glucose Transporter Type 4; D007473:Ion Channels; D007527:Isoenzymes; D024101:Mitochondrial Proteins; D047493:PPAR alpha; C000604389:UCP2 protein, human; C000604392:UCP3 protein, human; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3; D015094:3-Hydroxyacyl CoA Dehydrogenases; D007770:L-Lactate Dehydrogenase; D000080864:Lactate Dehydrogenase 5; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D030481:Pyruvate Dehydrogenase (Lipoamide); D002950:Citrate (si)-Synthase; D009218:Myosins