| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Astrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden; Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
2 Astrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
3 Department of Laboratory Medicine, Karolinska Institutet, S-141 86 Stockholm, Sweden
4 Astrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden; Dept of Physiology and Pharmacology, Karolinska Institutet, Stockholm, 171 77, Sweden
* To whom correspondence should be addressed. E-mail: eva.blomstrand{at}gih.se.
The gain in muscle mass as a result of resistance training is dependent on changes in both anabolic and catabolic reactions. A frequency of 2-3 exercise sessions a week is considered optimal for muscle gain in untrained individuals. Our hypothesis was that a second exercise session would enlarge the anabolic response and/or decrease the catabolic response. Eight male subjects performed resistance exercise on two occasions separated by 2 days. Muscle biopsies were taken from the vastus lateralis before and 15 min, 1 and 2 h after exercise. Exercise led to several-fold increases in phosphorylation of mTOR at Ser2448, p70S6 kinase (p70S6k) at Ser424/Thr421 and Thr389 and ribosomal protein S6, which persisted up to 2 h of recovery on both occasions. There was a tendency to a larger effect of the second exercise on p70S6k and S6, but the difference did not reach statistical significance. The mRNA expression of MuRF-1, which increased after exercise, was 30% lower after the second exercise session than after the first one. MAFbx expression was not altered after exercise, but down-regulated 30% 48h later, whereas myostatin expression was reduced by 45% after the first exercise and remained low until after the second exercise session. The results indicate that 1) changes in expression of genes involved in protein degradation are attenuated as a response to repetitive resistance training with minor additional increases in enzymes regulating protein synthesis and 2) the two ubiquitin-ligases, MuRF-1 and MAFbx, are differently affected by the exercise as well as by repeated exercise.
This article has been cited by other articles:
|
|
 |
|
  R. A. Dennis, H. Zhu, P. M. Kortebein, H. M. Bush, J. F. Harvey, D. H. Sullivan, and C. A. Peterson Muscle expression of genes associated with inflammation, growth, and remodeling is strongly correlated in older adults with resistance training outcomes Physiol Genomics, July 9, 2009; 38(2): 169 - 175. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. J. Hulmi, J. Tannerstedt, H. Selanne, H. Kainulainen, V. Kovanen, and A. A. Mero Resistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in men J Appl Physiol, May 1, 2009; 106(5): 1720 - 1729. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Tannerstedt, W. Apro, and E. Blomstrand Maximal lengthening contractions induce different signaling responses in the type I and type II fibers of human skeletal muscle J Appl Physiol, April 1, 2009; 106(4): 1412 - 1418. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Drummond, H. C. Dreyer, C. S. Fry, E. L. Glynn, and B. B. Rasmussen Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling J Appl Physiol, April 1, 2009; 106(4): 1374 - 1384. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. G. Coffey, H. Pilegaard, A. P. Garnham, B. J. O'Brien, and J. A. Hawley Consecutive bouts of diverse contractile activity alter acute responses in human skeletal muscle J Appl Physiol, April 1, 2009; 106(4): 1187 - 1197. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. R Moore, M. J Robinson, J. L Fry, J. E Tang, E. I Glover, S. B Wilkinson, T. Prior, M. A Tarnopolsky, and S. M Phillips Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men Am. J. Clinical Nutrition, January 1, 2009; 89(1): 161 - 168. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
