ISSN:
1432-2013
Keywords:
Mitogen-activated protein kinase One-leg exercise Skeletal muscle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract. The mitogen-activated protein (MAP) kinase pathways have been highlighted as a possible link between exercise and adaptive changes in skeletal muscle. In this study, the effect of exercise intensity on the activation of the ERK/MAP kinase pathway was investigated in human skeletal muscle. One-leg exercise at low (40% maximal oxygen consumption, VO2max, for 30 min) and high (75% VO2max for 30 min) intensity resulted in 11.5±8.1-fold and 39.7±6.3-fold (mean ±SEM) increases in ERK1/2 phosphorylation (P〈0.001), respectively. The phosphorylation of MEK1/2, the upstream kinase of ERK1/2, increased with exercise intensity (P〈0.05) to 2.5±0.9 and 4.8±1.1 times the basal level at the low and high intensity, respectively. The statistical analysis revealed a systematic difference between basal, low and high intensity exercise levels for both kinases. There was no change in the phosphorylation of either kinase in the non-exercised leg. The phosphorylation of the transcription factor cyclic AMP response element binding protein (CREB), a possible downstream target of the ERK/MAP kinase signalling pathway, was unaffected by exercise. The phosphorylation of ERK1/2 was significantly higher in purified freeze-dried compared to crude wet muscle after exercise, whereas the opposite pattern was observed for CREB. In conclusion, phosphorylation of ERK1/2 and MEK1/2 increases in an exercise intensity-dependent manner in human skeletal muscle and this seems to originate in the muscle fibres themselves.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004240000417
Permalink