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Resistance exercise and protein intake down regulate myostatin mRNA in human skeletal muscle
Author(s) -
Pilegaard Henriette,
Speerschneider Tobias,
Willumsen Nicholas,
Köhnke Richard,
Kristensen Kristina Møller,
Damsgaard Rasmus,
Saltin Bengt
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a390
Subject(s) - myostatin , myod , myogenin , muscle hypertrophy , endocrinology , medicine , skeletal muscle , messenger rna , resistance training , biology , gene , biochemistry , myogenesis
Resistance exercise induces muscle hypertrophy. Increased protein intake exaggerates this response (Tipton et al. 2001), but the underlying mechanism is discussed (Bohe et al. 2003). To test the hypothesis that protein supplementation after resistance exercise will affect exercise‐induced mRNA responses of myostatin, IGF‐I’s and/or MRF’s, eight young male subjects completed two identical trials with resistance exercise for the thigh muscles. Muscle biopsies were obtained from vastus lateralis before exercise and at 6h, 24h and 48h of recovery. Food intake was standardized with normal food provided in a control trial (CON; 15% protein) and increased protein on the exercise day in the other trial (PRO; 29%). Myostatin mRNA was in both trials reduced (P<0.05 in CON, P<0.1 in PRO) at 24h of recovery to 50% of before exercise and was lower (P<0.05) in PRO than CON at 48h of recovery. The mRNA contents of IGF‐IEa and IGF‐IEb were unaffected and MGF mRNA increased (2 fold) similarly non‐significantly at 48h. The MRF4 and MyoD mRNA content was elevated (P<0.05) 2 fold at 6h of recovery in both trials, while myogenin mRNA was higher (P<0.05) at all time points in both trials than before exercise and with no differences between trials. In conclusion, protein supplementation may act by prolonging the exercise‐induced down regulation of myostatin, which in turn may accelerate the removal of myostatin and allow for muscle growth.