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document
Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle . We recently showed that resistance exercise and ingestion of essential amino acids with carbohydrate ( EAA+CHO ) can independently stimulate mammalian target of rapamycin ( mTOR ) signaling and muscle protein synthesis in humans . Providing an EAA+CHO solution postexercise can further increase muscle protein synthesis . Therefore , we hypothesized that enhanced mTOR signaling might be responsible for the greater muscle protein synthesis when leucine-enriched EAA+CHOs are ingested during postexercise recovery . Sixteen male subjects were randomized to one of two groups ( control or EAA+CHO ) . The EAA+CHO group ingested the nutrient solution 1 h after resistance exercise . mTOR signaling was assessed by immunoblotting from repeated muscle biopsy samples . Mixed muscle fractional synthetic rate ( FSR ) was measured using stable isotope techniques . Muscle protein synthesis and 4E-BP1 phosphorylation during exercise were significantly reduced ( P < 0.05 ) . Postexercise FSR was elevated above baseline in both groups at 1 h but was even further elevated in the EAA+CHO group at 2 h postexercise ( P < 0.05 ) . Increased FSR was associated with enhanced phosphorylation of mTOR and S6K1 ( P < 0.05 ) . Akt phosphorylation was elevated at 1 h and returned to baseline by 2 h in the control group , but it remained elevated in the EAA+CHO group ( P < 0.05 ) . 4E-BP1 phosphorylation returned to baseline during recovery in control but became elevated when EAA+CHO was ingested ( P < 0.05 ) . eEF2 phosphorylation decreased at 1 and 2 h postexercise to a similar extent in both groups ( P < 0.05 ) . Our data suggest that enhanced activation of the mTOR signaling pathway is playing a role in the greater synthesis of muscle proteins when resistance exercise is followed by EAA+CHO ingestion .
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Intervention_Pharmacological
essential amino acids with carbohydrate ( EAA+CHO )
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Intervention_Control
control
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Intervention_Pharmacological
EAA+CHO
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Intervention_Pharmacological
EAA+CHO group
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Intervention_Pharmacological
nutrient solution
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Intervention_Physical
resistance exercise
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Intervention_Physical
immunoblotting from repeated muscle biopsy samples
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Outcome_Physical
mTOR signaling
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Outcome_Physical
Mixed muscle fractional synthetic rate ( FSR )
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Outcome_Physical
Muscle protein synthesis and 4E-BP1 phosphorylation
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Outcome_Physical
Postexercise FSR
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Outcome_Physical
Increased FSR
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Outcome_Physical
Akt phosphorylation
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Outcome_Physical
4E-BP1 phosphorylation
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Outcome_Physical
eEF2 phosphorylation
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Participant_Sample-size
Sixteen
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Participant_Sex
male