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Sprint exercise enhances skeletal muscle p70S6k phosphorylation and more so in women than in men.
MedLine Citation:
PMID:  22268492     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
AIM: Sprint exercise is characterized by repeated sessions of brief intermittent exercise at a high relative workload. However, little is known about the effect on mTOR pathway, an important link in the regulation of muscle protein synthesis. An earlier training study showed a greater increase in muscle fibre cross-sectional area in women than men. Therefore, we tested the hypothesis that the activation of mTOR signalling is more pronounced in women than in men. Healthy men (n = 9) and women (n = 8) performed three bouts of 30-s sprint exercise with 20-min rest in between. METHODS: Multiple blood samples were collected over time, and muscle biopsy specimens were obtained at rest and 140 min after the last sprint. RESULTS: Serum insulin increased by sprint exercise and more so in women than in men [gender (g) × time (t)]: P = 0.04. In skeletal muscle, phosphorylation of Akt increased by 50% (t, P = 0.001) and mTOR by 120% (t, P = 0.002) independent of gender. The elevation in p70S6k phosphorylation was larger in women (g × t, P = 0.03) and averaged 230% (P = 0.006) as compared to 60% in men (P = 0.04). Phosphorylation rpS6 increased by 660% over time independent of gender (t, P = 0.003). Increase in the phosphorylation of p70S6k was directly related to increase in serum insulin (r = 0.68, P = 0.004). CONCLUSION: It is concluded that repeated 30-s all-out bouts of sprint exercise separated by 20 min of rest increases Akt/mTOR signalling in skeletal muscle. Secondly, signalling downstream of mTOR was stronger in women than in men after sprint exercise indicated by the increased phosphorylation of p70S6k.
Authors:
M Esbjörnsson; H C Rundqvist; H Mascher; T Osterlund; O Rooyackers; E Blomstrand; E Jansson
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-1-23
Journal Detail:
Title:  Acta physiologica (Oxford, England)     Volume:  -     ISSN:  1748-1716     ISO Abbreviation:  -     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2012-1-24     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101262545     Medline TA:  Acta Physiol (Oxf)     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2011 The Authors Acta Physiologica © 2011 Scandinavian Physiological Society.
Affiliation:
Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden.
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