Effects of leucine-enriched essential amino acid and whey protein bolus dosing upon skeletal muscle protein synthesis at rest and after exercise in older women.

Autor: Wilkinson DJ; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Bukhari SSI; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Phillips BE; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Limb MC; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Cegielski J; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Brook MS; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Rankin D; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Mitchell WK; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Kobayashi H; Ajinomoto Co., Inc., Tokyo 104-8315, Japan., Williams JP; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Lund J; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Greenhaff PL; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Smith K; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK., Atherton PJ; MRC/ARUK Centre of Excellence for Musculoskeletal Ageing Research, National Institute for Health Research Nottingham Biomedical Research Centre, University of Nottingham, Derby DE22 3DT, UK. Electronic address: philip.atherton@nottingham.ac.uk.
Jazyk: angličtina
Zdroj: Clinical nutrition (Edinburgh, Scotland) [Clin Nutr] 2018 Dec; Vol. 37 (6 Pt A), pp. 2011-2021. Date of Electronic Publication: 2017 Sep 23.
DOI: 10.1016/j.clnu.2017.09.008
Abstrakt: Background & Aims: Impaired anabolic responses to nutrition and exercise contribute to loss of skeletal muscle mass with ageing (sarcopenia). Here, we tested responses of muscle protein synthesis (MPS), in the under represented group of older women, to leucine-enriched essential amino acids (EAA) in comparison to a large bolus of whey protein (WP).
Methods: Twenty-four older women (65 ± 1 y) received (N = 8/group) 1.5 g leucine-enriched EAA supplements (LEAA_1.5), 6 g LEAA (LEAA_6) in comparison to 40 g WP. A primed constant I.V infusion of 13 C 6 -phenylalanine was used to determine MPS at baseline and in response to feeding (FED) and feeding-plus-exercise (FED-EX; 6 × 8 unilateral leg extensions; 75%1-RM). We quantified plasma insulin/AA concentrations, leg femoral blood flow (LBF)/muscle microvascular blood flow (MBF), and anabolic signalling via immunoblotting.
Results: Plasma insulineamia and EAAemia were greater and more prolonged with WP than LEAA, although LEAA_6 peaked at similar levels to WP. Neither LEAA or WP modified LBF or MBF. FED increased MPS similarly in the LEAA_1.5, LEAA_6 and WP (P < 0.05) groups over 0-2 h, with MPS significantly higher than basal in the LEAA_6 and WP groups only over 0-4 h. However, FED-EX increased MPS similarly across all the groups from 0 to 4 h (P < 0.05). Only p-p70S6K1 increased with WP at 2 h in FED (P < 0.05), and at 2/4 h in FED-EX (P < 0.05).
Conclusions: In conclusion, LEAA_1.5, despite only providing 0.6 g of leucine, robustly (perhaps maximally) stimulated MPS, with negligible trophic advantage of greater doses of LEAA or even to 40 g WP. Highlighting that composition of EAA, in particular the presence of leucine rather than amount is most crucial for anabolism.
(Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: