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Intake of low-dose leucine-rich essential amino acids stimulates muscle anabolism equivalently to bolus whey protein in older women at rest and after exercise

Bukhari, Syed S.I.; Phillips, Bethan E.; Wilkinson, Daniel J.; Limb, Marie C.; Rankin, Debbie; Mitchell, William K.; Kobayashi, Hisamine; Greenhaff, Paul L.; Smith, Kenneth; Atherton, Philip J.

Authors

Syed S.I. Bukhari

BETH PHILLIPS beth.phillips@nottingham.ac.uk
Professor of Translational Physiology

Marie C. Limb

Debbie Rankin

William K. Mitchell

Hisamine Kobayashi

PAUL GREENHAFF PAUL.GREENHAFF@NOTTINGHAM.AC.UK
Professor of Muscle Metabolism

KENNETH SMITH KEN.SMITH@NOTTINGHAM.AC.UK
Professor of Metabolic Mass Spectrometry

PHILIP ATHERTON philip.atherton@nottingham.ac.uk
Professor of Clinical, metabolic & Molecular Physiology



Abstract

© 2015 American Physiological Society. All Rights Reseved. Dysregulated anabolic responses to nutrition/exercise may contribute to sarcopenia; however, these characteristics are poorly defined in female populations. We determined the effects of two feeding regimes in older women (66 ± 2.5 yr; n = 8/group): bolus whey protein (WP-20 g) or novel low-dose leucine-enriched essential amino acids (EAA) [LEAA; 3 g (40% leucine)]. Using [13C6]phenylalanine infusions, we quantified muscle (MPS) and albumin (APS) protein synthesis at baseline and in response to both feeding (FED) and feeding plus exercise (FED-EX; 6X8 knee extensions at 75% 1-repetition maximum). We also quantified plasma insulin/AA concentrations, whole leg (LBF)/muscle microvascular blood flow (MBF), and muscle anabolic signaling by phosphoimmunoblotting. Plasma insulinemia and EAA/aemia were markedly greater after WP than LEAA (P < 0.001). Neither LEAA nor WP modified LBF in response to FED or FED-EX, whereas MBF increased to a similar extent in both groups only after FED-EX (P < 0.05). In response to FED, both WP and LEAA equally stimulated MPS 0-2 h (P < 0.05), abating thereafter (0-4 h, P > 0.05). In contrast, after FED-EX, MPS increased at 0-2 h and remained elevated at 0-4 h (P < 0.05) with both WP and LEAA. No anabolic signals quantifiably increased after FED, but p70 S6K1 Thr389 increased after FED-EX (2 h, P < 0.05). APS increased similarly after WP and LEAA. Older women remain subtly responsive to nutrition ± exercise. Intriguingly though, bolus WP offers no trophic advantage over LEAA.

Citation

Bukhari, S. S., Phillips, B. E., Wilkinson, D. J., Limb, M. C., Rankin, D., Mitchell, W. K., …Atherton, P. J. (2015). Intake of low-dose leucine-rich essential amino acids stimulates muscle anabolism equivalently to bolus whey protein in older women at rest and after exercise. AJP - Endocrinology and Metabolism, 308(12), E1056-E1065. https://doi.org/10.1152/ajpendo.00481.2014

Journal Article Type Article
Acceptance Date Mar 26, 2015
Online Publication Date Mar 31, 2015
Publication Date Jun 15, 2015
Deposit Date Sep 6, 2018
Journal American Journal of Physiology - Endocrinology and Metabolism
Print ISSN 0193-1849
Electronic ISSN 1522-1555
Publisher American Physiological Society
Peer Reviewed Peer Reviewed
Volume 308
Issue 12
Pages E1056-E1065
DOI https://doi.org/10.1152/ajpendo.00481.2014
Keywords Skeletal muscle, Blood flow, Protein synthesis, Aging, Amino acids, Exercise
Public URL https://nottingham-repository.worktribe.com/output/1113610
Publisher URL https://journals.physiology.org/doi/abs/10.1152/ajpendo.00481.2014
PMID 25827594