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Resistance exercise increases leg muscle protein synthesis and mTOR signalling independent of sex
Author(s) -
Dreyer H. C.,
Fujita S.,
Glynn E. L.,
Drummond M. J.,
Volpi E.,
Rasmussen B. B.
Publication year - 2010
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2010.02074.x
Subject(s) - endocrinology , medicine , pi3k/akt/mtor pathway , skeletal muscle , p70 s6 kinase 1 , phosphorylation , biology , protein kinase b , effector , signal transduction , microbiology and biotechnology
Aim: Sex differences are evident in human skeletal muscle as the cross‐sectional area of individual muscle fibres is greater in men than in women. We have recently shown that resistance exercise stimulates mammalian target of rapamycin (mTOR) signalling and muscle protein synthesis in humans during early post‐exercise recovery. Therefore, the aim of this study was to determine if sex influences the muscle protein synthesis response during recovery from resistance exercise. Methods: Seventeen subjects, nine male and eight female, were studied in the fasted state before, during and for 2 h following a bout of high‐intensity leg resistance exercise. Mixed muscle protein fractional synthetic rate was measured using stable isotope techniques and mTOR signalling was assessed by immunoblotting from repeated vastus lateralis muscle biopsy samples. Results: Post‐exercise muscle protein synthesis increased by 52% in the men and by 47% in the women ( P < 0.05) and was not different between groups ( P > 0.05). Akt phosphorylation increased in both groups at 1 h post‐exercise ( P < 0.05) and returned to baseline during 2 h post‐exercise with no differences between groups ( P > 0.05). Phosphorylation of mTOR and its downstream effector S6K1 increased significantly and similarly between groups during post‐exercise recovery ( P < 0.05). eEF2 phosphorylation decreased at 1‐ and 2 h post‐exercise ( P < 0.05) to a similar extent in both groups. Conclusion: The contraction‐induced increase in early post‐exercise mTOR signalling and muscle protein synthesis is independent of sex and appears to not play a role in the sexual dimorphism of leg skeletal muscle in young men and women.