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.

نویسندگان

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

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 [(13)C6]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; 6 × 8 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 Thr(389) 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.

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منابع مشابه

CALL FOR PAPERS Endocrine and Metabolic Dysfunction During Aging and Senescence 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

Syed S. I. Bukhari,* Bethan E. Phillips,* Daniel J. Wilkinson, Marie C. Limb, Debbie Rankin, William K. Mitchell, Hisamine Kobayashi, Paul L. Greenhaff, Kenneth Smith, and Philip J. Atherton Medical Research Council/Arthritis Research United Kingdom Centre of Excellence for Musculoskeletal Ageing Research, University of Nottingham, Derby, United Kingdom; and Ajinomoto Company Incorporated, Toky...

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عنوان ژورنال:
  • American journal of physiology. Endocrinology and metabolism

دوره 308 12  شماره 

صفحات  -

تاریخ انتشار 2015