Cited by 66Circadian rhythm and melatoninAdipose Tissue and MetabolismMitochondrial Function and Pathology

Endurance training ameliorates the metabolic and performance characteristics of circadian Clock mutant mice

Pastore, Stephen, Hood, David A.·2013·Journal of Applied Physiology

Abstract

Circadian locomotor output cycles kaput (CLOCK) is a nuclear transcription factor that is a component of the central autoregulatory feedback loop that governs the generation of biological rhythms. Homozygous Clock mutant mice contain a truncated CLOCK Δ19 protein within somatic cells, subsequently causing an impaired ability to rhythmically transactivate circadian genes. The present study sought to investigate whether the Clock mutation affects mitochondrial physiology within skeletal muscle, as well as the responsiveness of these mutant animals to adapt to a chronic voluntary endurance training protocol. Within muscle, Clock mutant mice displayed 44% and 45% reductions in peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC-1α) and mitochondrial transcription factor-A protein content, respectively, and an accompanying 16% decrease in mitochondrial content, as determined by cytochrome c oxidase enzyme activity. These decrements contributed to a 50% decrease in exercise tolerance in Clock mutant mice. Interestingly, the Clock mutation did not appear to alter subsarcolemmal or intermyofibrillar mitochondrial respiration within muscle or systemic glucose tolerance. Daily locomotor activity levels were similar between wild-type and Clock mutant mice throughout the training protocol. Endurance training ameliorated the decrease in PGC-1α protein expression and mitochondrial content in the Clock mutant mice, eliciting a 2.9-fold improvement in exercise tolerance. Thus our data suggest that a functional CLOCK protein is essential to ensure the maintenance of mitochondrial content within muscle although the absence of a functional CLOCK protein does not impair the ability of animals to adapt to chronic exercise.

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Crossref · 10.1152/japplphysiol.01505.2012

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Authors
Pastore, S., & Hood, D. A.
Affiliations
York University (CA)
Corresponding author
Hood, David A.
Venue
Journal of Applied Physiology
Published
2013-04-15
Volume
114
Issue
8
Pages
1076-1084
ISSN
  • 0161-7567 (ISSN-L)
  • 8750-7587
  • 1522-1601
OpenAlex
W1968877294
Cited by
66
References
58
Citations by year
2026: 5 · 2025: 8 · 2024: 3 · 2023: 6 · 2022: 5 · 2021: 2 · 2020: 6 · 2019: 5 · 2018: 4 · 2017: 5 · 2016: 7 · 2015: 6 · 2014: 3 · 2013: 1
FWCI
3.05
Type
journal article
Language
en
Open access
closed
Locations
  • Journal of Applied Physiology (publishedVersion)
  • PubMed (publishedVersion)
Funders
York University
Topics
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Health Sciences › Medicine › Physiology › Adipose Tissue and Metabolism
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Mitochondrial Function and Pathology
Keywords
circadian clock, Clock mutant mice, endurance training, skeletal muscle mitochondria, PGC-1α, TFAM, exercise tolerance, glucose tolerance, mitochondrial respiration, circadian rhythm, exercise adaptation
MeSH terms
Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha, Adaptation, Physiological, Animals, Blood Glucose, Circadian Rhythm, Electron Transport Complex IV, DNA-Binding Proteins, Exercise Test, High Mobility Group Proteins, Male, Mice, Inbred C57BL, Mice, Mutant Strains, Mitochondria, Muscle, Motor Activity, Muscle Contraction, Mutation, Physical Endurance, Sarcolemma, Time Factors, Transcription Factors, Trans-Activators, Exercise Tolerance, Muscle, Skeletal, Mice, CLOCK Proteins

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