Increasing whole-body energetic stress does not augment fasting-induced changes in human skeletal muscle.
Pflugers Arch
; 473(2): 241-252, 2021 02.
Article
em En
| MEDLINE
| ID: mdl-33420549
ABSTRACT
Fasting rapidly (≤ 6 h) activates mitochondrial biogenic pathways in rodent muscle, an effect that is absent in human muscle following prolonged (10-72 h) fasting. We tested the hypotheses that fasting-induced changes in human muscle occur shortly after food withdrawal and are modulated by whole-body energetic stress. Vastus lateralis biopsies were obtained from ten healthy males before, during (4 h), and after (8 h) two supervised fasts performed with (FAST+EX) or without (FAST) 2 h of arm ergometer exercise (~ 400 kcal of added energy expenditure). PGC-1α mRNA (primary outcome measure) was non-significantly reduced (p = 0.065 [ηp2 = 0.14]) whereas PGC-1α protein decreased (main effect of time p < 0.01) during both FAST and FAST+EX. P53 acetylation increased in both conditions (main effect of time p < 0.01) whereas ACC and SIRT1 phosphorylation were non-significantly decreased (both p < 0.06 [ηp2 = 0.15]). Fasting-induced increases in NFE2L2 and NRF1 protein were observed (main effects of time p < 0.03), though TFAM and COXIV protein remained unchanged (p > 0.05). Elevating whole-body energetic stress blunted the increase in p53 mRNA, which was apparent during FAST only (condition × time interaction p = 0.04). Select autophagy/mitophagy regulators (LC3BI, LC3BII, BNIP3) were non-significantly reduced at the protein level (p ≤ 0.09 [ηp2 > 0.13]) but the LC3III ratio was unchanged (p > 0.05). PDK4 mRNA (p < 0.01) and intramuscular triglyceride content in type IIA fibers (p = 0.04) increased similarly during both conditions. Taken together, human skeletal muscle signaling, mRNA/protein expression, and substrate storage appear to be unaffected by whole-body energetic stress during the initial hours of fasting.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Exercício Físico
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Jejum
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Restrição Calórica
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Metabolismo Energético
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Músculo Quadríceps
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Mitocôndrias Musculares
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Contração Muscular
Tipo de estudo:
Clinical_trials
Limite:
Adolescent
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Adult
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Humans
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Male
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article