A number of limitations exist in the current study. Firstly, we only assessed the relative changes in the phosphorlated levels of various Akt/mTOR pathway intermediates. Thus, these can only be used as markers indicative of MPS. We did not measure protein synthesis directly and thus caution needs to be taken when interpreting changes in phosphorylation status of signaling pathway intermediates to imply changes in human MPS, as this does not always determine functional changes. Secondly, no control was used and thus
no direct comparison between isoenergetic carbohydrate and whey protein and resistance exercise could be made. However, previous research has clearly indicated that resistance exercise robustly activates Akt/mTOR signalling. Thirdly,
only one dosage was used (10 g) and thus any comparison between other dosages XMU-MP-1 ic50 cannot be made directly. Finally, our study focused on the early post-exercise recovery response in signalling and, therefore, we acknowledge the possibility that long-term activation of Akt/mTOR signalling and its downstream targets such as at 6, 24, or 48 hr post-exercise may be better indicators of muscle MPS over the course of a resistance training program. In conclusion, the present study shows that ingestion of 10 g whey protein (5.25 C646 g EAAs) prior to a single bout of lower body resistance exercise had no significant effect on activating systemic and cellular signaling intermediates of the Akt/mTOR pathway, otherwise indicative of MPS, in untrained men. Future research should examine the effects of dose response and timing of protein ingestion and compare the effects of various forms/fractions of proteins Adenosine triphosphate on post-exercise cell signalling responses to resistance exercise. Acknowledgements The authors would like to thank the study participants for their hard work and willingness to donate blood and muscle biopsy samples. This work was supported by Glanbia Nutritionals, Twin Falls,
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