The degree of aminoacidemia after dairy protein ingestion does not modulate the postexercise anabolic response in young men: a randomized controlled trial

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dc.contributor.author Chan, AH en
dc.contributor.author D'Souza, RF en
dc.contributor.author Beals, JW en
dc.contributor.author Zeng, N en
dc.contributor.author Prodhan, U en
dc.contributor.author Fanning, AC en
dc.contributor.author Poppitt, Sally en
dc.contributor.author Li, Z en
dc.contributor.author Burd, NA en
dc.contributor.author Cameron-Smith, David en
dc.contributor.author Mitchell, Cameron en
dc.date.accessioned 2019-10-29T02:27:13Z en
dc.date.issued 2019-09 en
dc.identifier.uri http://hdl.handle.net/2292/48724 en
dc.description.abstract BACKGROUND:Resistance exercise and dietary protein stimulate muscle protein synthesis (MPS). The rate at which proteins are digested and absorbed into circulation alters peak plasma amino acid concentrations and may modulate postexercise MPS. A novel mineral modified milk protein concentrate (mMPC), with identical amino acid composition to standard milk protein concentrate (MPC), was formulated to induce rapid aminoacidemia. OBJECTIVES:The aim of this study was to determine whether rapid aminoacidemia and greater peak essential amino acid (EAA) concentrations induced by mMPC would stimulate greater postresistance exercise MPS, anabolic signaling, and ribosome biogenesis compared to standard dairy proteins, which induce a small but sustained plasma essential aminoacidemia. METHODS:Thirty healthy young men (22.5 ± 3.0 y; BMI 23.8 ± 2.7 kg/m2) received primed constant infusions of l-[ring-13C6]-phenylalanine and completed 3 sets of leg presses and leg extensions at 80% of 1 repetition. Afterwards, participants were randomly assigned in a double-blind fashion to consume 25 g mMPC, MPC, or calcium caseinate (CAS). Vastus lateralis biopsies were collected at rest, and 2 and 4 h post exercise. RESULTS:Plasma EAA concentrations, including leucine, were 19.2-26.6% greater in the mMPC group 45-90 min post ingestion than in MPC and CAS groups (P < 0.001). Myofibrillar fractional synthetic rate from baseline to 4 h was increased by 82.6 ± 64.8%, 137.8 ± 72.1%, and 140.6 ± 52.4% in the MPC, mMPC, and CAS groups, respectively, with no difference between groups (P = 0.548). Phosphorylation of anabolic signaling targets (P70S6KThr389, P70S6KThr421/Ser424, RPS6Ser235/236, RPS6Ser240/244, P90RSKSer380, 4EBP1) were elevated by <3-fold at both 2 and 4 h post exercise in all groups (P < 0.05). CONCLUSIONS:The amplitude of plasma leucine and EAA concentrations does not modulate the anabolic response to resistance exercise after ingestion of 25 g dairy protein in young men. This trial was registered at http://www.anzctr.org.au/ as ACTRN12617000393358. en
dc.publisher Oxford University Press en
dc.relation.ispartofseries Journal of Nutrition 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.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.title The degree of aminoacidemia after dairy protein ingestion does not modulate the postexercise anabolic response in young men: a randomized controlled trial en
dc.type Journal Article en
dc.identifier.doi 10.1093/jn/nxz099 en
pubs.issue 9 en
pubs.begin-page 1511 en
pubs.volume 149 en
dc.rights.holder Copyright: The author en
pubs.end-page 1522 en
dc.rights.accessrights http://purl.org/eprint/accessRights/RestrictedAccess en
pubs.subtype Article en
pubs.elements-id 778949 en
pubs.org-id Science en
pubs.org-id Biological Sciences en
dc.identifier.eissn 1541-6100 en
pubs.record-created-at-source-date 2019-08-14 en
pubs.dimensions-id 31152658 en


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