| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Health and Kinseiology, Texas A&M University, College Station, TX, USA
2 Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
3 Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
4 Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
5 Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Central Arkansas Veterans Health Care System, Little Rock, AR, USA
* To whom correspondence should be addressed. E-mail: jfluckey{at}hlkn.tamu.edu.
Recent studies have implicated the mTOR signaling pathway as a primary component for muscle growth in mammals. The purpose of this investigation was to examine signaling pathways for muscle protein synthesis after resistance exercise. Sprague-Dawley rats (male, 6 months old) were assigned to either resistance exercise or control groups. Resistance exercise was accomplished in operantly conditioned animals using a specially designed flywheel apparatus. Rats performed two sessions of resistance exercise, separated by 48 h, each consisting of 2 sets of 25 repetitions. Sixteen hours after the second session, animals were sacrificed, and soleus muscles were examined for rates of protein synthesis with and without insulin and/or rapamycin (mTOR inhibitor) and/or (PD)098059 (MEK-kinase inhibitor). Results of this study demonstrated that rates of synthesis were higher (p<0.05) with insulin after exercise in comparison to without insulin, or to control muscles, regardless of insulin. Rapamycin lowered (p<0.05) rates of synthesis in controls, with or without insulin, and after exercise without insulin. However, insulin was able to overcome the inhibition of rapamycin after exercise (p<0.05). PD had no effect on protein synthesis in control rats, but the addition of PD to exercised muscle resulted in lower (p<0.05) rates of synthesis, and this inhibition was not rescued by insulin. Western blot analyses demonstrated that the inhibitors used in the present study were selective and effective for preventing activation of specific signaling proteins. Together, these results suggest that the insulin-facilitated increase of muscle protein synthesis after resistance exercise requires multiple signaling pathways.
This article has been cited by other articles:
|
|
 |
|
  M. J. Drummond, H. C. Dreyer, B. Pennings, C. S. Fry, S. Dhanani, E. L. Dillon, M. Sheffield-Moore, E. Volpi, and B. B. Rasmussen Skeletal muscle protein anabolic response to resistance exercise and essential amino acids is delayed with aging J Appl Physiol, May 1, 2008; 104(5): 1452 - 1461. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Frosig, M. P. Sajan, S. J. Maarbjerg, N. Brandt, C. Roepstorff, J. F. P. Wojtaszewski, B. Kiens, R. V. Farese, and E. A. Richter Exercise improves phosphatidylinositol-3,4,5-trisphosphate responsiveness of atypical protein kinase C and interacts with insulin signalling to peptide elongation in human skeletal muscle J. Physiol., August 1, 2007; 582(3): 1289 - 1301. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
