Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/24827
Appears in Collections:Faculty of Health Sciences and Sport Journal Articles
Peer Review Status: Refereed
Title: Postexercise High-Fat Feeding Suppresses p70S6K1 Activity in Human Skeletal Muscle
Authors: Hammond, Kelly M
Impey, Samuel G
Currell, Kevin
Mitchell, Nigel
Shepherd, Sam O
Jeromson, Stewart
Hawley, John A
Close, Graeme L
Hamilton, David Lee
Sharples, Adam P
Morton, James P
Contact Email: d.l.hamilton@stir.ac.uk
Issue Date: Nov-2016
Citation: Hammond KM, Impey SG, Currell K, Mitchell N, Shepherd SO, Jeromson S, Hawley JA, Close GL, Hamilton DL, Sharples AP & Morton JP (2016) Postexercise High-Fat Feeding Suppresses p70S6K1 Activity in Human Skeletal Muscle, Medicine and Science in Sports and Exercise, 48 (11), pp. 2108-2117.
Abstract: Purpose: This study aimed to examine the effects of reduced CHO but high postexercise fat availability on cell signaling and expression of genes with putative roles in regulation of mitochondrial biogenesis, lipid metabolism, and muscle protein synthesis.  Methods: Ten males completed a twice per day exercise model (3.5 h between sessions) comprising morning high-intensity interval training (8 × 5 min at 85% V·O2peak) and afternoon steady-state (SS) running (60 min at 70% V·O2peak). In a repeated-measures design, runners exercised under different isoenergetic dietary conditions consisting of high-CHO (HCHO: 10 g·kg-1CHO, 2.5 g·kg-1protein, and 0.8 g·kg-1fat for the entire trial period) or reduced-CHO but high-fat availability in the postexercise recovery periods (HFAT: 2.5 g·kg-1CHO, 2.5 g·kg-1protein, and 3.5 g·kg-1fat for the entire trial period).  Results: Muscle glycogen was lower (P< 0.05) at 3 h (251 vs 301 mmol·kg-1dry weight) and 15 h (182 vs 312 mmol·kg-1dry weight) post-SS exercise in HFAT compared with HCHO. Adenosine monophosphate-activated protein kinase [alpha]2 activity was not increased post-SS in either condition (P= 0.41), although comparable increases (allP< 0.05) in PGC-1[alpha], p53, citrate synthase, Tfam, peroxisome proliferator-activated receptor, and estrogen-related receptor [alpha] mRNA were observed in HCHO and HFAT. By contrast, PDK4 (P= 0.003), CD36 (P= 0.05), and carnitine palmitoyltransferase 1 (P= 0.03) mRNA were greater in HFAT in the recovery period from SS exercise compared with HCHO. Ribosomal protein S6 kinase activity was higher (P= 0.08) at 3 h post-SS exercise in HCHO versus HFAT (72.7 ± 51.9 vs 44.7 ± 27 fmol·min-1·mg-1).  Conclusion: Postexercise high-fat feeding does not augment the mRNA expression of genes associated with regulatory roles in mitochondrial biogenesis, although it does increase lipid gene expression. However, postexercise ribosomal protein S6 kinase 1 activity is reduced under conditions of high-fat feeding, thus potentially impairing skeletal muscle remodeling processes.
DOI Link: http://dx.doi.org/10.1249/mss.0000000000001009
Rights: This item has been embargoed for a period. During the embargo please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study. This is a non-final version of an article published in final form in Medicine & Science in Sports & Exercise' Issue: Volume 48(11), November 2016, p 2108–2117. Available at: https://doi.org/10.1249/MSS.0000000000001009

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