Hammond, KM, Impey, SG, Currell, K, Mitchell, N, Shepherd, SO, Jeromson, S, Hawley, JA, Close, GL, Hamilton, LD and Sharples, AP (2016) Postexercise High-Fat Feeding Suppresses p70S6K1 Activity in Human Skeletal Muscle. Medicine and Science in Sports And Exercise, 48 (11). 2108 - 2117.

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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−1 CHO, 2.5 g·kg−1 protein, and 0.8 g·kg−1 fat for the entire trial period) or reduced-CHO but high-fat availability in the postexercise recovery periods (HFAT: 2.5 g·kg−1 CHO, 2.5 g·kg−1 protein, and 3.5 g·kg−1 fat for the entire trial period).

Results Muscle glycogen was lower (P < 0.05) at 3 h (251 vs 301 mmol·kg−1 dry weight) and 15 h (182 vs 312 mmol·kg−1 dry weight) post-SS exercise in HFAT compared with HCHO. Adenosine monophosphate-activated protein kinase α2 activity was not increased post-SS in either condition (P = 0.41), although comparable increases (all P < 0.05) in PGC-1α, p53, citrate synthase, Tfam, peroxisome proliferator-activated receptor, and estrogen-related receptor α 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.

Item Type: Article
Additional Information: This is not the final published version. The final published version can be found online at 10.1249/MSS.0000000000001009
Uncontrolled Keywords: AMPK-α2, PGC-1α, p53, GLYCOGEN, MITOCHONDRIAL BIOGENESIS
Subjects: Q Science > Q Science (General)
R Medicine > R Medicine (General)
Divisions: Faculty of Medicine and Health Sciences > Institute for Science and Technology in Medicine
Related URLs:
Depositing User: Symplectic
Date Deposited: 25 Jul 2017 09:54
Last Modified: 05 Apr 2019 14:58
URI: http://eprints.keele.ac.uk/id/eprint/3791

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