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| Name | Class |
|---|---|
| University of Waterloo | OTHER |
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This study examines the impact of increasing energetic stress during an 8-hour fast on metabolic pathways in human skeletal muscle. Specifically, participants will undergo two 8-hour fasting sessions in a randomized crossover fashion, with the addition of low-intensity arm exercise in one of the sessions. Changes in metabolic pathways will be examined in resting (leg) muscle before, during, and after the fast.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| FAST+EX - FAST | Experimental | FAST+EX then FAST alone |
|
| FAST - FAST+EX | Experimental | FAST alone then FAST+EX |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| FAST+EX | Other | Participants will perform 2-hours of low-intensity arm exercise (8 x 15 min bouts of arm ergometer exercise separated by 10 min of rest) during an 8-hour fast. |
|
| Measure | Description | Time Frame |
|---|---|---|
| Peroxisome proliferator activated receptor gamma co-activator 1-alpha (PGC-1α) messenger ribonucleic acid (mRNA) expression | PGC-1α gene expression (indirect indicator of PGC-1α activity) | 15 min before fast; after 4 and 8 hours of fasting |
| Measure | Description | Time Frame |
|---|---|---|
| Catecholamine concentrations | Epinephrine and norepinephrine concentrations in plasma samples | 15 min before fast; after exercise; after 4 and 8 hours of fasting |
| Glucose and insulin concentrations |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Brendon J. Gurd, PhD | Queen's University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| School of Kinesiology and Health Studies | Kingston | Ontario | K7L3N6 | Canada |
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Allocation concealment, assessor blinding
| FAST | Other | Participants will complete an 8-hour fast. |
|
Glucose and insulin concentrations in plasma samples
| 15 min before fast; after 4 and 8 hours of fasting |
| total and phosphorylated AMP activated protein kinase (AMPK) | active AMPK relative to total AMPK protein content | 15 min before fast; after 4 and 8 hours of fasting |
| total and phosphorylated SIRT-1 | active SIRT-1 relative to total SIRT1 protein content | 15 min before fast; after 4 and 8 hours of fasting |
| total and phosphorylated mammalian target of rapamycin (mTOR) | active mTOR relative to total mTOR protein content | 15 min before fast; after 4 and 8 hours of fasting |
| total and phosphorylated Akt/Protein Kinase B | active Akt relative to total Akt protein content | 15 min before fast; after 4 and 8 hours of fasting |
| total and phosphorylated acetyl coenzyme A carboxylase (ACC) | active ACC relative to total ACC protein | 15 min before fast; after 4 and 8 hours of fasting |
| total and phosphorylated p38 mitogen activated protein kinase (MAPK) | active p38 MAPK relative to total p38 MAPK protein | 15 min before fast; after 4 and 8 hours of fasting |
| phosphorylated protein kinase A (PKA) substrates | phosphorylated PKA substrates (indirect measure of PKA activity) | 15 min before fast; after 4 and 8 hours of fasting |
| acetylated p53 | p53 acetylation status (indirect measure of SIRT-1 deacetylase activity) | 15 min before fast; after 4 and 8 hours of fasting |
| Sirtuin 1 (SIRT1) mRNA expression | gene expression of the deacetylase enzyme SIRT1 | 15 min before fast; after 4 and 8 hours of fasting |
| Sirtuin 3 (SIRT3) mRNA expression | gene expression of the deacetylase enzyme SIRT3 | 15 min before fast; after 4 and 8 hours of fasting |
| Pyruvate dehydrogenase kinase isoenzyme 4 (PDK4) mRNA expression | gene expression of the PGC-1α target PDK4 | 15 min before fast; after 4 and 8 hours of fasting |
| p53 mRNA expression | gene expression of the tumour suppressor protein p53 | 15 min before fast; after 4 and 8 hours of fasting |
| Leucine rich pentatricopeptide repeat containing protein (LRP130) mRNA expression | gene expression of RNA-binding protein LRP130 | 15 min before fast; after 4 and 8 hours of fasting |
| General control non-repressible 5 (GCN5) mRNA expression | gene expression of the acetyltransferase GCN5 | 15 min before fast; after 4 and 8 hours of fasting |
| PGC-1α protein content | Protein content of the transcriptional co-activator PGC-1α | 15 min before fast; after 4 and 8 hours of fasting |
| Cytochrome C oxidase subunit 4 (COX-IV) protein content | Protein content of the mitochondrial enzyme COX subunit 4 | 15 min before fast; after 4 and 8 hours of fasting |
| Intramuscular glycogen content | Muscle glycogen content | 15 min before fast; after 4 and 8 hours of fasting |
| Intramuscular triglyceride (IMTG) content | Muscle IMTG content | 15 min before fast; after 4 and 8 hours of fasting |