Short-term muscle disuse lowers myofibrillar protein synthesis rates and induces anabolic resistance to protein ingestion
Wall, BT; Dirks, ML; Snijders, T; et al.van Dijk, J-W; Fritsch, M; Verdijk, LB; van Loon, LJC
Date: 15 January 2016
Journal
AJP - Endocrinology and Metabolism
Publisher
American Physiological Society -
Publisher DOI
Related links
Abstract
Disuse leads to rapid loss of skeletal muscle mass and function. It has been hypothesized that short successive periods of muscle disuse throughout the lifespan play an important role in the development of sarcopenia. The physiological mechanisms underlying short-term muscle disuse atrophy remain to be elucidated. We assessed the impact ...
Disuse leads to rapid loss of skeletal muscle mass and function. It has been hypothesized that short successive periods of muscle disuse throughout the lifespan play an important role in the development of sarcopenia. The physiological mechanisms underlying short-term muscle disuse atrophy remain to be elucidated. We assessed the impact of 5 days of muscle disuse on postabsorptive and postprandial myofibrillar protein synthesis rates in humans. Twelve healthy young (22 ± 1 yr) men underwent a 5-day period of one-legged knee immobilization (full leg cast). Quadriceps cross-sectional area (CSA) of both legs was assessed before and after immobilization. Continuous infusions of l-[ring-(2)H5]phenylalanine and l-[1-(13)C]leucine were combined with the ingestion of a 25-g bolus of intrinsically l-[1-(13)C]phenylalanine- and l-[1-(13)C]leucine-labeled dietary protein to assess myofibrillar muscle protein fractional synthetic rates in the immobilized and nonimmobilized control leg. Immobilization led to a 3.9 ± 0.6% decrease in quadriceps muscle CSA of the immobilized leg. Based on the l-[ring-(2)H5]phenylalanine tracer, immobilization reduced postabsorptive myofibrillar protein synthesis rates by 41 ± 13% (0.015 ± 0.002 vs. 0.032 ± 0.005%/h, P < 0.01) and postprandial myofibrillar protein synthesis rates by 53 ± 4% (0.020 ± 0.002 vs. 0.044 ± 0.003%/h, P < 0.01). Comparable results were found using the l-[1-(13)C]leucine tracer. Following protein ingestion, myofibrillar protein bound l-[1-(13)C]phenylalanine enrichments were 53 ± 18% lower in the immobilized compared with the control leg (0.007 ± 0.002 and 0.015 ± 0.002 mole% excess, respectively, P < 0.05). We conclude that 5 days of muscle disuse substantially lowers postabsorptive myofibrillar protein synthesis rates and induces anabolic resistance to protein ingestion.
Sport and Health Sciences
Collections of Former Colleges
Item views 0
Full item downloads 0
Related items
Showing items related by title, author, creator and subject.
-
The effect of priming exercise on O2 uptake kinetics, muscle O2 delivery and utilization, muscle activity, and exercise tolerance in boys
Barker, AR; Trebilcock, E; Breese, Brynmor C.; et al. (NRC Research Press (Canadian Science Publishing), 1 March 2014)This study used priming exercise in young boys to investigate (i) how muscle oxygen delivery and oxygen utilization, and muscle activity modulate oxygen uptake kinetics during exercise; and (ii) whether the accelerated ... -
One Week of Bed Rest Leads to Substantial Muscle Atrophy and Induces Whole-Body Insulin Resistance in the Absence of Skeletal Muscle Lipid Accumulation.
Dirks, ML; Wall, BT; van de Valk, B; et al. (American Diabetes Association, 29 June 2016)Short (<10 days) periods of muscle disuse, often necessary for recovery from illness or injury, lead to various negative health consequences. The current study investigated mechanisms underlying disuse-induced insulin ... -
The mechanistic bases of the power-time relationship: muscle metabolic responses and relationships to muscle fibre type
Vanhatalo, A; Black, MI; DiMenna, FJ; et al. (Wiley, 4 March 2016)We hypothesised that: 1) the critical power (CP) will represent a boundary separating steady state from non-steady state muscle metabolic responses during whole-body exercise and 2) that the CP and the W′ (curvature constant ...