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mTOR signaling following Essential Amino Acid + Carbohydrate Ingestion in Young and Older Subjects
Author(s) -
Dreyer Hans Christian,
Fujita Satoshi,
Drummond Micah John,
Rasmussen Blake,
Volip Elena
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.958.14
Subject(s) - ingestion , anabolism , pi3k/akt/mtor pathway , p70 s6 kinase 1 , phosphorylation , endocrinology , medicine , protein kinase b , biology , signal transduction , biochemistry
Essential amino acid (EAA) ingestion can stimulate muscle protein synthesis in young and older subjects. In older subjects however, the addition of carbohydrate (CHO) (EAA+CHO) has been shown to blunt the anabolic response as compared to young subjects and may be due to dysregulation of the anabolic (mTOR) signaling pathway. PURPOSE: The purpose of this study was to determine the signaling response after ingestion of EAA + CHO in young and older muscle and to determine if the response between groups was different. METHODS: Immunoblotting methods were used to determine cell signaling of an anabolic pathway (mTOR), at 1 and 2hr post EAA+CHO ingestion. RESULTS: Our preliminary results from 4 young and 5 older subjects demonstrate that Akt, mTOR, S6K1 and 4E‐BP1 phosphorylation increased following EAA+CHO ingestion while eEF2 phosphorylation decreased only in young. In addition there was a trend for 4E‐BP1 phosphorylation to be greater in the young at 1h post ingestion (P=0.09). CONCLUSIONS: Our preliminary findings suggest that a potential differential response to EAA+CHO ingestion exists between young and old. This response may indicate that both translation initiation (4E‐BP1 phosphorylation) and elongation (eEF2 dephosphorylation) may be attenuated in the old. Further research in needed to elucidate the potential differential response between young and old muscle following EAA+CHO ingestion. This work was supported by a Pepper Pilot Project award