Comparing The Post-Exercise Anabolic Response To Dairy Protein Fractions With Different Amino Acid Profiles

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dc.contributor.advisor Cameron-Smith, D en
dc.contributor.advisor Mitchell, C en
dc.contributor.author Chan, Alex en
dc.date.accessioned 2018-06-14T03:08:27Z en
dc.date.issued 2018 en
dc.identifier.uri http://hdl.handle.net/2292/37276 en
dc.description Available to authenticated members of The University of Auckland. en
dc.description.abstract Introduction: Resistance exercise is a robust stimulator of the mammalian target of rapamycin complex 1 (mTORC1) pathway which contributes to net muscle protein accretion by activating muscle protein synthesis (MPS). MPS occurs at the ribosomes and is limited by both ribosomal translational efficiency and capacity. Dairy proteins are enriched in essential amino acids (EAA), particularly leucine, which are potent stimulators of the mTOR pathway. The rate at which amino acids are digested and delivered to the muscle may modulate the post-exercise MPS response. Aim: To investigate how different milk protein fractions evoking varying rates of aminoacidemia affect post-exercise MPS along with its regulators. Methods: 30 healthy males (22.6 ± 3.0 years, BMI: 23.8 ± 2.7 kg/m2 ) completed three sets of both leg press and leg extensions at 80% of their one repetition maximum until the point of fatigue. Immediately afterwards, in a double-blind manner, participants consumed 25 g of either calcium caseinate (CAS), milk protein concentrate (MPC), or a proprietary MPC (pMPC) that has the same AA composition but evokes a rapid aminoacidemia. Vastus lateralis biopsies were collected before, 2, and 4 hours postexercise and supplement ingestion. Data were analysed using 2-way ANOVA with repeated measurements. Results: pMPC induced the greatest peak concentration of EAA and BCAA between 45 and 90 min, when compared to MPC and CAS, which both had a similar AA response. Despite the significant difference in plasma aminoacidemia, myofibrillar FSR and anabolic signalling were elevated above baseline with no difference between groups. There was a trend for an increase in 45S pre-rRNA at 4 hours, which would suggest the initiation of ribosome biogenesis. Conclusion: In young untrained men, a rapid increase in aminoacidemia does not further modulate anabolic signalling up to 4 hours after resistance exercise and protein ingestion. Protein dose and amino acid composition appear to be more important than the delivery profile in regulating post-exercise MPS in this population. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99265070612602091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.title Comparing The Post-Exercise Anabolic Response To Dairy Protein Fractions With Different Amino Acid Profiles en
dc.type Thesis en
thesis.degree.discipline Biomedical Science en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Masters en
dc.rights.holder Copyright: The author en
pubs.elements-id 744693 en
pubs.org-id Science en
pubs.org-id Biological Sciences en
pubs.record-created-at-source-date 2018-06-14 en


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