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Nutritional energy in the regulation of human muscle mTOR signaling following resistance exercise
Author(s) -
Glynn Erin L,
Fry Christopher S,
Drummond Micah J,
Dreyer Hans C,
Dhanani Shaheen,
Volpi Elena,
Rasmussen Blake B
Publication year - 2008
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.22.1_supplement.959.19
Subject(s) - pi3k/akt/mtor pathway , p70 s6 kinase 1 , ingestion , protein kinase b , phosphorylation , endocrinology , medicine , insulin resistance , ex vivo , rptor , chemistry , biology , signal transduction , insulin , biochemistry , in vitro
Resistance exercise (Ex) stimulates the mammalian target of rapamycin (mTOR) signaling pathway. The ingestion of leucine‐enriched essential amino acids and carbohydrate (EAA+CHO) 1 hr following Ex further stimulates mTOR signaling. The purpose of this study was to determine whether the addition of nutritional energy to a EAA+CHO stimulus following Ex enhances mTOR signaling. Sixteen male subjects were randomized to two groups containing an equivalent amount of EAA (∼20g) but different amounts of CHO. Both groups ingested the nutrient solution 1 hr after a bout of Ex. mTOR signaling was assessed by immunoblotting from muscle biopsy samples at baseline, immediately following, and 1 and 2 hr post‐Ex. There were no differences between groups for any proteins measured prior to nutrient ingestion. At 2 hr post‐Ex (following nutrient ingestion) the phosphorylation status of mTOR and its downstream effectors S6K1 and 4E‐BP1 increased with no differences between groups (P>0.05). However, Akt/PKB phosphorylation was higher in the extra energy group, likely due to increased blood insulin concentration (P<0.05). We conclude that mTOR signaling is not further enhanced, despite increased Akt activation, by the availability of additional energy (carbohydrates) following Ex as compared to a stimulus containing the same amount of EAA and approximately half the caloric energy. Funded by NIH Grant # 5R01AR049877