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Constantin-Teodosiu, Dumitru, Cederblad, Gitten, Bergstrom, Mats and Greenhaff, Paul L. (2018) Maximal-intensity exercise does not fully restore muscle pyruvate dehydrogenase complex activation after 3 days of high-fat dietary intake. Clinical Nutrition . ISSN 1532-1983

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Abstract

Background & aims: Exercise activates muscle pyruvate dehydrogenase complex (PDC), but moderate intensity exercise fails to fully activate muscle PDC after high-fat diet [1]. We investigated whether maximal intensity exercise overcomes this inhibition.

Methods: Quadriceps femoris muscle biopsy samples were obtained from healthy males at rest, and after 46 and 92 electrically-evoked maximal intermittent isometric contractions, which were preceded by 3 days of either low- (18%) or high- (69%) isocaloric dietary fat intake (LFD and HFD, respectively).

Results: The ratio of PDCa (active form) to total PDCt (fully activated) at rest was 50% less after HFD (0.32 ± 0.01 vs 0.15 ± 0.01; P<0.05). This ratio increased to 0.77 ± 0.06 after 46 contractions (P<0.001) and to 0.98 ± 0.07 after 92 contractions (P<0.001) in LFD. The corresponding values after HFD were less (0.54 ± 0.06; P<0.01 and 0.70 ± 0.07; P<0.01, respectively). Resting muscle acetyl-CoA and acetylcarnitine content was greater after HFD than LFD (both P<0.05), but their rate of accumulation in the former was reduced during contraction. Muscle lactate content after 92 contractions was 30% greater after HFD (P<0.05). Muscle force generation during contraction was no different between interventions, but HFD lengthened muscle relaxation time (P<0.05). Daily urinary total carnitine excretion after HFD was 2.5-fold greater than after LFD (P<0.01).

Conclusions: A bout of maximal intense exercise did not overcome dietary fat-mediated inhibition of muscle pyruvate dehydrogenase complex activation, and was associated with greater muscle lactate accumulation, as a result of lower PDC flux, and increased muscle relaxation time.

Item Type:	Article
Keywords:	Diet ; Maximal intensity contraction ; PDC activation ; Carnitine
Schools/Departments:	University of Nottingham, UK > Faculty of Medicine and Health Sciences > School of Life Sciences
Identification Number:	https://doi.org/10.1016/j.clnu.2018.02.001
Depositing User:	Constantin-Teodosiu, Tim
Date Deposited:	23 Mar 2018 12:14
Last Modified:	15 Feb 2019 04:30
URI:	https://eprints.nottingham.ac.uk/id/eprint/50275

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