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Time-dependent regulation of postprandial muscle protein synthesis rates after milk protein ingestion in young men
Vliet, Stephan Van Beals, Joseph W. Holwerda, Andrew M. Emmons, Russell S. Goessens, Joy P. Paluska, Scott A. Lisio, Michael De van Loon, Luc J. C. Burd, Nicholas A.
Vliet, Stephan Van
Beals, Joseph W.
Holwerda, Andrew M.
Emmons, Russell S.
Goessens, Joy P.
Paluska, Scott A.
Lisio, Michael De
van Loon, Luc J. C.
Burd, Nicholas A.
Abstract
The anabolic action of “fast” whey protein on the regulation of postprandial muscle protein synthesis has been established to be short-lived in healthy young adults. We assessed the time course of anabolic signaling activation and stimulation of myofibrillar protein synthesis rates (MPS) after ingestion of a food source that represents a more typical meal-induced pattern of aminoacidemia. Seven young men (age: 22 ± 1 y) underwent repeated blood and biopsy sampling during primed, continuous l-[ring-2H5]phenylalanine and l-[1-13C]leucine tracer infusions and ingested 38 g of l-[1-13C]phenylalanine- and l-[1-13C]leucine-labeled milk protein concentrate. A total of ∼27 ± 4 (∼10 g) and ∼31 ± 1% (∼12 g) of dietary protein-derived amino acids were released in circulation between 0 and 120 min and 120–300 min, respectively, of the postprandial period. l-[ring-2H5]phenylalanine-based MPS increased above basal (0.025 ± 0.008%/h) by ∼75% (0.043 ± 0.009%/h; P = 0.05) between 0 and 120 min and by ∼86% (0.046 ± 0.004%/h; P = 0.02) between 120 and 300 min, respectively. l-[1-13C]leucine-based MPS increased above basal (0.027 ± 0.002%/h) by ∼72% (0.051 ± 0.016%/h; P = 0.10) between 0 and 120 min and by ∼62% (0.047 ± 0.004%/h; P = 0.001) between 120 and 300 min, respectively. Myofibrillar protein-bound l-[1-13C]phenylalanine increased over time (P < 0.001) and equaled 0.004 ± 0.001, 0.008 ± 0.002, 0.017 ± 0.004, and 0.020 ± 0.003 mole percent excess at 60, 120, 180, and 300 min, respectively, of the postprandial period. Milk protein ingestion increased mTORC1 phosphorylation at 120, 180, and 300 min of the postprandial period (all P < 0.05). Our results show that ingestion of 38 g of milk protein results in sustained increases in MPS throughout a 5-h postprandial period in healthy young men.
Keywords
anabolic signaling, leucine, mammalian target of rapamycin, muscle mass regulation, nutrition
Date
2019
Type
Journal article
Journal
Journal of Applied Physiology
Book
Volume
127
Issue
6
Page Range
1792-1801
Article Number
ACU Department
Centre for Exercise and Nutrition
Faculty of Health Sciences
Faculty of Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
Published as green open access
License
File Access
Open
Controlled
Controlled