Jevons, EFP, Gejl, KD, Strauss, JA, Ørtenblad, N and Shepherd, SO (2020) Skeletal muscle lipid droplets are resynthesized before being coated with perilipin proteins following prolonged exercise in elite male triathletes. American Journal of Physiology Endocrinology and Metabolism, 318 (3). E357-E370. ISSN 0193-1849
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Abstract
Intramuscular triglycerides (IMTG) are a key substrate during prolonged exercise, but little is known about the rate of IMTG resynthesis in the post-exercise period. We investigated the hypothesis that the distribution of the lipid droplet (LD)-associated perilipin (PLIN) proteins is linked to IMTG storage following exercise. 14 elite male triathletes (27±1 y, 66.5±1.3 mL.kg-1.min-1) completed 4 h of moderate-intensity cycling. During the first 4 h of recovery, subjects received either carbohydrate or H2O, after which both groups received carbohydrate. Muscle biopsies collected pre and post-exercise, and 4 h and 24 h post-exercise were analysed using confocal immunofluorescence microscopy for fibre type-specific IMTG content and PLIN distribution with LDs. Exercise reduced IMTG content in type I fibres (-53%, P=0.002), with no change in type IIa fibres. During the first 4 h of recovery, IMTG content increased in type I fibres (P=0.014), but was not increased further after 24 h where it was similar to baseline levels in both conditions. During recovery the number of LDs labelled with PLIN2 (70%), PLIN3 (63%) and PLIN5 (62%; all P<0.05) all increased in type I fibres. Importantly, the increase in LDs labelled with PLIN proteins only occurred at 24 h post-exercise. In conclusion, IMTG resynthesis occurs rapidly in type I fibres following prolonged exercise in highly-trained individuals. Further, increases in IMTG content following exercise preceded an increase in the number of LDs labelled with PLIN proteins. These data, therefore, suggest that the PLIN proteins do not play a key role in post-exercise IMTG resynthesis.
Item Type: | Article |
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Uncontrolled Keywords: | 06 Biological Sciences, 11 Medical and Health Sciences |
Subjects: | R Medicine > RC Internal medicine > RC1200 Sports Medicine |
Divisions: | Sport & Exercise Sciences |
Publisher: | American Psychological Society |
Related URLs: | |
Date Deposited: | 21 Jan 2020 12:15 |
Last Modified: | 04 Sep 2021 08:06 |
DOI or ID number: | 10.1152/ajpendo.00399.2019 |
URI: | https://researchonline.ljmu.ac.uk/id/eprint/12070 |
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