Interaction of contractile activity and training history on mRNA abundance

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From  Vernon G. Coffey,1 Anthony Shield,1 Benedict J. Canny,2
Kate A. Carey,3 David Cameron-Smith,3 and John A. Hawley1
Coffey, Vernon G., Anthony Shield, Benedict J. Canny, Kate A.
Carey, David Cameron-Smith, and John A. Hawley. Interaction of
contractile activity and training history on mRNA abundance in
skeletal muscle from trained athletes. Am J Physiol Endocrinol Metab
290: E849–E855, 2006. First published December 6, 2005;
doi:10.1152/ajpendo.00299.2005.—Skeletal muscle displays enormous
plasticity to respond to contractile activity with muscle from
strength- (ST) and endurance-trained (ET) athletes representing diverse
states of the adaptation continuum. Training adaptation can be
viewed as the accumulation of specific proteins. Hence, the altered
gene expression that allows for changes in protein concentration is of
major importance for any training adaptation. Accordingly, the aim of
the present study was to quantify acute subcellular responses in
muscle to habitual and unfamiliar exercise. After 24-h diet/exercise
control, 13 male subjects (7 ST and 6 ET) performed a random order
of either resistance (8
5 maximal leg extensions) or endurance
exercise (1 h of cycling at 70% peak O2 uptake). Muscle biopsies were
taken from vastus lateralis at rest and 3 h after exercise. Gene
expression was analyzed using real-time PCR with changes normalized
relative to preexercise values. After cycling exercise, peroxisome
proliferator-activated receptor- coactivator-1 (ET 8.5-fold, ST
10-fold, P  0.001), pyruvate dehydrogenase kinase-4 (PDK-4; ET
26-fold, ST 39-fold), vascular endothelial growth factor (VEGF;
ET 4.5-fold, ST 4-fold), and muscle atrophy F-box protein
(MAFbx) (ET 2-fold, ST 0.4-fold) mRNA increased in both
groups, whereas MyoD (3-fold), myogenin (0.9-fold), and myostatin
(2-fold) mRNA increased in ET but not in ST (P  0.05).
After resistance exercise PDK-4 (7-fold, P  0.01) and MyoD
(0.7-fold) increased, whereas MAFbx (0.7-fold) and myostatin
(0.6-fold) decreased in ET but not in ST. We conclude that prior
training history can modify the acute gene responses in skeletal
muscle to subsequent exercise.