Heather Petrick

Heather Petrick
University of Guelph | UOGuelph · Department of Human Health and Nutritional Sciences (HHNS)

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34
Publications
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172
Citations

Publications

Publications (34)
Article
Within brown adipose tissue (BAT), the brain isoform of creatine kinase (CKB) has been proposed to regulate the regeneration of ADP and phosphocreatine in a futile creatine cycle (FCC) that stimulates energy expenditure. However, the presence of FCC, and the specific creatine kinase isoforms regulating this theoretical model within white adipose ti...
Article
Rapid oscillations in cytosolic calcium (Ca ²⁺ ) coordinate muscle contraction, relaxation, and physical movement. Intriguingly, dietary nitrate decreases ATP cost of contraction, increases force production, and increases cytosolic Ca ²⁺ ; which would seemingly necessitate a greater demand for sarcoplasmic reticulum Ca ²⁺ ATPase (SERCA) to sequeste...
Article
Full-text available
Dietary nitrate supplementation, and the subsequent serial reduction to nitric oxide, has been shown to improve glucose homeostasis in several pre-clinical models of obesity and insulin resistance. While the mechanisms remain poorly defined, the beneficial effects of nitrate appear to be partially dependent on AMPK-mediated signaling events, a cent...
Article
We aimed to determine the combined effects of over-expressing FABPpm and CD36 on skeletal muscle fatty acid transport to establish if these transport proteins function collaboratively. Electrotransfection with either FABPpm or CD36 increased their protein content at the plasma membrane (+75% and +64%), increased fatty acid transport rates +24% for...
Article
The liver is particularly susceptible to the detrimental effects of a high fat diet (HFD), rapidly developing lipid accumulation and impaired cellular homeostasis. Recently, dietary nitrate has been shown to attenuate HFD-induced whole body glucose intolerance and liver steatosis, however the underlying mechanism(s) remain poorly defined. In the cu...
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Reductions in mitochondrial function have been proposed to cause insulin resistance, however the possibility that impairments in insulin signaling negatively affects mitochondrial bioenergetics has received little attention. Therefore, we tested the hypothesis that insulin could rapidly improve mitochondrial ADP sensitivity, a key process linked to...
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Full-text available
Acute elevations in inflammatory cytokines have been demonstrated to increase aortic and left ventricular stiffness and reduce endothelial function in healthy subjects. As vascular and cardiac function are often transiently reduced following prolonged exercise, it is possible that cytokines released during exercise may contribute to these alteratio...
Article
Purpose: Sprint interval training (SIT) has gained popularity as a time-effective alternative to moderate-intensity endurance training (END). However, whether SIT is equally effective for decreasing cardiometabolic risk factors remains debatable, as many beneficial effects of exercise are thought to be transient and, unlike END, SIT is not recomme...
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Cardiac function has been shown to transiently decrease following prolonged exercise, with greater durations related to increased impairment. However, the prospective assessment of exercise duration on cardiac performance is rare, and the influence of relative exercise intensity is typically not assessed in relation to these changes. The aim of thi...
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Obesity is associated with adipose tissue hypertrophy, systemic inflammation, mitochondrial dysfunction, and intestinal dysbiosis. Rodent models of high fat diet (HFD)-feeding or genetic deletion of multi-functional proteins involved in immunity and metabolism are often used to probe the aetiology of obesity; however, these models make it difficult...
Article
Purpose: Ultra-endurance exercise is steadily growing in popularity; however, the impact of increasingly prolonged durations of exercise on the vascular endothelium is unknown. The aim of this study was to characterize the impact of various ultramarathon running distances on vascular form and function. Methods: We evaluated vascular endothelial...
Article
Key points: Ketone bodies are proposed to represent an alternative fuel source driving energy production, particularly during exercise. Biologically, the extent to which mitochondria utilize ketone bodies compared to other substrates remains unknown. We demonstrate in vitro that maximal mitochondrial respiration supported by ketone bodies is low w...
Article
Type 1 and type 2 diabetes are both tightly associated with impaired glucose control. While both pathologies stem from different mechanisms, a reduction in insulin action coincides with drastic metabolic dysfunction in skeletal muscle and metabolic inflexibility. However, the underlying explanation for this response remains poorly understood, parti...
Article
White adipose tissue (WAT) dysfunction in obesity is implicated in the onset of whole-body insulin resistance. Alterations in mitochondrial bioenergetics, namely impaired mitochondrial respiration and increased mitochondrial reactive oxygen species (mtROS) production, have been suggested to contribute to this metabolic dysregulation. However, techn...
Article
Key points: Dietary nitrate is a prominent therapeutic strategy to mitigate some metabolic deleterious effects related to obesity. Mitochondrial dysfunction is causally linked to adipose tissue inflammation and insulin resistance. Whole-body glucose tolerance is prevented by nitrate independent of body weight and energy expenditure. Dietary nitrat...
Article
Dietary nitrate has been shown to increase cytosolic calcium concentrations within the heart, which would necessitate greater calcium sequestration for relaxation. In the present study we demonstrate that while nitrate supplementation reduced blood pressure, calcium-handling protein content, sarco(endo)plasmic reticulum Ca-ATPase 2a (SERCA) enzymat...
Article
Key points: -We determined if bed rest increased mitochondrial derived reactive oxygen species and cellular redox stress, contributing to the induction insulin resistance -Bed rest decreased maximal and submaximal ADP-stimulated mitochondrial respiration -Bed rest did not alter mitochondrial H2 O2 emission in the presence of ADP concentrations ind...
Article
Full-text available
Introduction: In skeletal muscle, the Na/K ATPase (NKA) plays essential roles in processes linked to muscle contraction, fatigue, and energy metabolism; however, very little information exists regarding the regulation of NKA activity. The scarcity of information regarding NKA function in skeletal muscle likely stems from methodological constraints...
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Full-text available
Purpose: To use repeated control trials to measure within-subject variability and assess the existence of responders to ischemic preconditioning (IPC). Secondly, to determine whether repeated IPC can evoke a dosed ergogenic response. Methods: Twelve aerobically fit individuals each completed three control and three IPC 5-km cycling time trials....
Article
Key points: Blood flow restricted resistance exercise (BFR-RE) is capable of inducing comparable adaptations to traditional resistance exercise (RE), despite a lower total exercise volume. It has been suggested that an increase in reactive oxygen species (ROS) production may be involved in this response, however oxygen partial pressure (pO2 ) is r...
Article
Mitochondria possess an immense capacity for energy (ATP) production and are capable of dramatically increasing fat and carbohydrate oxidation during exercise to maintain cellular ATP concentrations. This process is regulated by exercise intensity, which influences the mobilization/delivery of substrates to the mitochondria and activates several pr...
Article
The decline in fat oxidation at higher power outputs of exercise is a complex interaction between several mechanisms; however, the influence of mitochondrial bioenergetics in this process remains elusive. Therefore, using permeabilized muscle fibers from mouse skeletal muscle, we aimed to determine if acute exercise altered mitochondrial sensitivit...
Article
The movement of lipids across mitochondrial membranes represents a rate-limiting step in fatty acid oxidation within the heart. A key regulatory point in this process is flux through carnitine palmitoyltransferase-I (CPT-I), an enzyme located on the outer mitochondrial membrane. Malonyl-CoA (M-CoA) is a naturally occurring inhibitor of CPT-I; there...

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