Physiology Commons^™

The Effects Of Exercise Training On Glucose Homeostasis And Muscle Metabolism In Type 1 Diabetic Female Mice, Caitlin O'Neill, Erica J. Locke, Darren A. Sipf, Jack Thompson, Erin Drebushenko, Nate Berger, Brooke Segich, Stephen C. Kolwicz Jr.

Health and Exercise Physiology Faculty Publications

Although exercise training is an important recommendation for the management of type 1 diabetes (T1D), most of the available research studies predominantly focus on male subjects. Given the importance of sex as a biological variable, additional studies are required to improve the knowledge gap regarding sex differences in T1D research. Therefore, the purpose of this study was to examine the role of exercise training in mediating changes in glucose homeostasis and skeletal muscle metabolism in T1D female mice. Female mice were injected with streptozotocin (STZ) to induce T1D. Two weeks after STZ injection, control (CON) and STZ mice were exercise …

No Changes In Appetite-Related Hormones Following Swimming And Cycling Exercise Interventions In Adults With Obesity, Brandon G. Fico, Mohammed Alkatan, Hirofumi Tanaka

International Journal of Exercise Science

International Journal of Exercise Science 13(2): 1819-1825, 2020. Swimming is a favorable and ideal modality of exercise for individuals with obesity and arthritis as it encompasses a minimal weight-bearing stress and a reduced heat load. However, the available evidence indicates that regular swimming may not be effective in reducing body weight and body fatness. A current hypothesis is that exercise in cold water stimulates appetite. We determined the effect of swimming training on appetite-related hormones. Thirty-nine adults with obesity and osteoarthritis were randomly assigned to 12 weeks of supervised swimming or cycling training. In the initial few weeks, participants exercised …

Pre-Exercise Maltodextrin Ingestion And Transient Hypoglycemia In Cycling And Running, Costas Chryssanthopoulos, Evangelia Tzeravini, Elias Zachrogiannis, Maria Megalou, Alexander Kokkinos, Maria Maridaki, George Dimitriadis, Michaella Alexandrou, Chrysoula Kontrafouri, Damianos Papafilippou, Argyro Pountoukidou, Effraimia Tsolaki, Maria Evangelia Koloutsou, Nikolaos Zacharodimos, Michael Koutsilieris, Anastassios Philippou

International Journal of Exercise Science

International Journal of Exercise Science 13(2): 1691-1704, 2020. This study examined the phenomenon of transient hypoglycemia and metabolic responses to pre-exercise carbohydrate (CHO) maltodextrin ingestion in cycling and running on the same individuals. Eleven active males cycled or ran for 30 min at 80% maximal heart rate (HRmax) after ingestion of either 1g/kg body mass maltodextrin (CHO-Cycle and CHO-Run respectively) or placebo (PL-Cycle and PL-Run) solutions. Fluids were ingested 30min before exercise in a double-blind and random manner.Blood glucose and serum insulin were higher before exercise in CHO (mean CHO-Cycle+CHO-Run) (Glucose: 7.4 ± 0.3 mmol^.l^-1; …

Postprandial Microvascular Blood Flow In Skeletal Muscle: Similarities And Disparities To The Hyperinsulinaemic-Euglycaemic Clamp, Katherine M. Roberts-Thomson, Andrew C. Betik, Dino Premilovac, Stephen Rattigan, Stephen M. Richards, Renee M. Ross, Ryan D. Russell, Gunveen Kaur, Lewan Parker, Michelle A. Keske

Health & Human Performance Faculty Publications and Presentations

Skeletal muscle contributes to ~40% of total body mass and has numerous important mechanical and metabolic roles in the body. Skeletal muscle is a major site for glucose disposal following a meal. Consequently, skeletal muscle plays an important role in postprandial blood glucose homeostasis. Over the past number of decades, research has demonstrated that insulin has an important role in vasodilating the vasculature in skeletal muscle in response to an insulin infusion (hyperinsulinaemic-euglycaemic clamp) or following the ingestion of a meal. This vascular action of insulin is pivotal for glucose disposal in skeletal muscle, as insulin-stimulated vasodilation increases the delivery …

Molecular Machinery For The ‘Kiss And Run’ Mechanism Of Insulin Secretion, Akshata Ramesh Naik

Wayne State University Dissertations

The insulin secreting porosome is a supramolecular lipo-protein complex that

measures roughly 100 – 120 nm in diameter. Porosomes allow transient fusion of insulin

secretory granules to the cell plasma membrane and mediates partial release of secretory

contents. Post secretion, the secretory granule reseals and re-enters to the cell interior.

This is in contrast to the ‘total fusion’ phenomenon, where secretory vesicles completely

fuse at the cell plasma membrane and release all of the contents to the cell exterior. This

study involved a deeper understanding of the transient or ‘kiss-and-run’ mechanism of

cell secretion that involves the insulin secreting porosome …

Insights Into The Therapeutic Potential Of Salt Inducible Kinase 1: A Novel Mechanism Of Metabolic Control, Randi Fitzgibbon

Dissertations & Theses (Open Access)

Salt inducible kinase 1 (SIK1) has been considered a stress-inducible kinase since it was first cloned in 1999. Continued efforts since this time have been dedicated to characterizing the structure and function of SIK1. Such research has laid the ground work for our understanding of SIK1 action and regulation in tissue and stimuli dependent manners. The fundamental findings of this dissertation continue in this tradition and include investigations of SIK1 regulatory mechanisms in skeletal muscle cells, the cellular and physiological effects of SIK1 loss of function in vitro and in vivo, and intracellular metabolic and mitochondrial regulation by this …

The Effect Of Insulin Treatment And Exercise Modality On Skeletal Muscle Fiber Size In Streptozotocin-Induced Type 1 Diabetic Rats, John Z. Nickels

Electronic Thesis and Dissertation Repository

Severe Type 1 Diabetes Mellitus (T1DM) is known to have several negative effects on skeletal muscle mass, a condition known as diabetic myopathy. One of these effects is the atrophy of the glycolytic muscle fibers. However, the role of intensity of insulin treatment and exercise modality in attenuating this loss in fiber cross-sectional area (CSA) specifically has yet to be determined. The purpose of this investigation was to determine the effects of 12 weeks of differing intensity of insulin therapy and exercise modality on the CSA of plantaris muscle fibers, identified by myosin heavy chain (MHC) of STZ-induced T1DM rats. …

Insulin And Ketones: Their Roles In Brain Mitochondrial Function, Sheryl Teresa Carr

Theses and Dissertations

The prevalence of both Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) is increasing worldwide, and the trends are unfortunately expected to continue. AD has recently been tied with mitochondrial dysfunction and insulin resistance, creating a mechanistic tie between AD and T2DM. Unfortunately, insulin resistance is often increased with aging and therefore, all individuals are at risk of brain mitochondrial dysfunction. Without proper mitochondrial function, the brain will degenerate, causing impaired cognitive function and reduced quality of life. The purpose of this study is two-fold: first, to understand the role of ceramides in insulin-induced brain mitochondrial dysfunction, and; second, …

Insulin And Ketones: Their Roles In Brain Mitochondrial Function, Sheryl Teresa Carr

Theses and Dissertations

The prevalence of both Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) is increasing worldwide, and the trends are unfortunately expected to continue. AD has recently been tied with mitochondrial dysfunction and insulin resistance, creating a mechanistic tie between AD and T2DM. Unfortunately, insulin resistance is often increased with aging and therefore, all individuals are at risk of brain mitochondrial dysfunction. Without proper mitochondrial function, the brain will degenerate, causing impaired cognitive function and reduced quality of life. The purpose of this study is two-fold: first, to understand the role of ceramides in insulin-induced brain mitochondrial dysfunction, and; second, …

Apolipoprotein E4 And Insulin Resistance Interact To Impair Cognition And Alter The Epigenome And Metabolome, Lance A. Johnson, Eileen Ruth S. Torres, Soren Impey, Jan F. Stevens, Jacob Raber

Physiology Faculty Publications

Apolipoprotein E4 (E4) and type 2 diabetes are major risk factors for cognitive decline and late onset Alzheimer’s disease (AD). E4-associated phenotypes and insulin resistance (IR) share several features and appear to interact in driving cognitive dysfunction. However, shared mechanisms that could explain their overlapping pathophysiology have yet to be found. We hypothesized that, compared to E3 mice, E4 mice would be more susceptible to the harmful cognitive effects of high fat diet (HFD)-induced IR due to apoE isoform-specific differences in brain metabolism. While both E3 and E4 mice fed HFD displayed impairments in peripheral metabolism and cognition, deficits in …

Diabetes-Induced Expression And Regulation Of Glp-1 Levels By Bile Acid Receptors (Tgr5 & Fxr), Joseph R. Spengler

Theses and Dissertations

Diabetes Mellitus has continued to drastically affect the health of the world and many complications can prove fatal. As long as this metabolic disease persist, research discoveries will need to continue to be made so that patient outcomes and healthcare are dramatically enhanced. In recent years, GLP-1 has been the topic of conversation for diabetes research, due to its promising effects in promoting insulin sensitivity. Furthermore, bile acids and their receptors (TGR5 & FXR) have shown promise in their actions in the regulation of GLP-1, and thus glucose homeostasis. Here we have shown the detection and increased expression of TGR5 …

Long-Term Treatment With Insulin And Retinoic Acid Increased Glucose Usage In L6 Muscle Cells Via Glycogenesis, Matthew Ray Goff

Doctoral Dissertations

Skeletal muscle glucose metabolism can affect whole body glucose homeostasis significantly. Vitamin A (VA) plays a role in a number of physiological functions including glucose metabolism. However, its role in skeletal muscle glucose metabolism has not been well established. Insulin controls glucose metabolism in the skeletal muscle via the regulations of glucose uptake, glycogenesis, and glycolysis. We hypothesize that insulin and VA signaling pathways may converge to regulate glucose metabolism in skeletal muscle. Here, the effects of retinoic acid (RA) alone and in combination with insulin on glucose utilization in rat L6 muscle cells were studied. L6 cells were treated …

Insulin Pump Therapy In Toddlers And Preschool Children With Type 1 Diabetes Mellitus, Jean Litton, Alan Rice, Nancy Friedman, Jon Oden, Mary Lee, Michael Freemark

Mary M. Lee

OBJECTIVE: To test whether glycemic control in young children could be achieved more effectively and safely by using continuous insulin infusions administered by insulin pumps.

STUDY DESIGN: We analyzed the effects of pump therapy in nine toddlers in whom type 1 diabetes developed between the ages of 10 and 40 months. After a mean of 13.7 months of therapy with multiple daily injections, patients were treated with insulin pumps for periods ranging from 7 to 19 months (mean, 12.7 months).

RESULTS: Before initiation of pump therapy, HbA1c levels averaged 9.5% +/- 0.4%, and patients had a mean of 0.52 episodes …

Parental Mastery Of Continuous Subcutaneous Insulin Infusion Skills And Glycemic Control In Youth With Type 1 Diabetes, Kathleen Mitchell, Kimberley Johnson, Karen Cullen, Mary M. Lee, Olga T. Hardy

Mary M. Lee

OBJECTIVE: The purpose of this study is to determine whether parental knowledge of the continuous subcutaneous insulin infusion (CSII) device affects glycemic control as measured by hemoglobin A1c (A1C) level. SUBJECTS AND METHODS: Parents of children with type 1 diabetes mellitus (T1DM) using CSII completed a 14-item questionnaire. Questions 1-10 were knowledge-based questions that required the parent to extract specific information from their child's CSII device. Questions 11-14 asked parents to provide a self-assessment of their CSII knowledge. RESULTS: Twenty-two parents of youth with T1DM participated in the study. Ten of the youth were in the Low-A1C group (A1C/=8%). Parents …

Peri-Exercise Co-Ingestion Of Branched-Chain Amino Acids And Carbohydrate In Men Does Not Preferentially Augment Resistance Exercise-Induced Increases In Pi3k/Akt-Mtor Pathway Markers Indicative Of Muscle Protein Synthesis, Maria Pontes Ferreira, Rui Li, Matthew Cooke, Richard B. Kreider, Darryn S. Willoughby

Nutrition and Food Science Faculty Research Publications

The effects of a single bout of resistance exercise (RE) in conjunction with peri-exercise branched chain amino acid (BCAA) and carbohydrate (CHO) ingestion on skeletal muscle signaling markers indicative of muscle protein synthesis (MPS) were determined. It was hypothesized that CHO + BCAA would elicit a more profound effect on these signaling markers compared to CHO. Twenty-seven males were randomly assigned to CHO, CHO + BCAA, or placebo (PLC) groups. Four sets of leg presses and leg extensions were performed at 80% 1RM. Supplements were ingested 30 min and immediately prior to and after RE. Venous blood and muscle biopsy …

The Role Of Glycogen Synthase Kinase 3 Beta In Skeletal Development, J. Ryan Gillespie

Electronic Thesis and Dissertation Repository

Glycogen Synthase Kinase 3 beta (GSK-3b) is an important node of regulation in many cellular signaling pathways including insulin and Wnt. Previous work has shown that ubiquitous deletion of GSK-3b is lethal and causes various skeletal abnormalities, but it is not known whether these defects are skeleton-intrinsic. A second GSK-3 protein which shares almost complete homology, GSK-3a, has been shown to have completely overlapping roles with the b form in some cases and independent functions in other cases. Therefore examination of the role of GSK-3b in skeletal development is very poignant.

To examine the role of GSK-3b in skeletal development …

Mice Deficient In Gem Gtpase Show Abnormal Glucose Homeostasis Due To Defects In Beta-Cell Calcium Handling, Jenny E. Gunton, Mary Sisavanh, Rebecca A. Stokes, Jon Satin, Leslie S. Satin, Min Zhang, Sue M. Liu, Weikang Cai, Kim Cheng, Gregory J. Cooney, D. Ross Laybutt, Trina So, Juan-Carlos Molero, Shane T. Grey, Douglas A. Andres, Michael S. Rolph, Charles R. Mackay

Physiology Faculty Publications

AIMS AND HYPOTHESIS: Glucose-stimulated insulin secretion from beta-cells is a tightly regulated process that requires calcium flux to trigger exocytosis of insulin-containing vesicles. Regulation of calcium handling in beta-cells remains incompletely understood. Gem, a member of the RGK (Rad/Gem/Kir) family regulates calcium channel handling in other cell types, and Gem over-expression inhibits insulin release in insulin-secreting Min6 cells. The aim of this study was to explore the role of Gem in insulin secretion. We hypothesised that Gem may regulate insulin secretion and thus affect glucose tolerance in vivo.

METHODS: Gem-deficient mice were generated and their metabolic phenotype characterised by in …

Map Kinases Couple Hindbrain-Derived Catecholamine Signals To Hypothalamic Adrenocortical Control Mechanisms During Glycemia-Related Challenges, Arshad M. Khan, Kimberly L. Kaminski, Graciela Sanchez-Watts, Todd A. Ponzio, J. Brent Kuzmiski, Jaideep S. Bains, Alan G. Watts

Arshad M. Khan, Ph.D.

No abstract provided.

The Effect Of Physical Activity On The Insulin Response To Frequent Meals, Michael E. Holmstrup

Exercise Science - Dissertations

Long, uninterrupted bouts of sedentary behavior are thought to negatively influence insulin sensitivity, and may impact metabolic function regardless of adherence to general physical activity guidelines. The purpose of this study was to determine the combined effect of physical activity (1 h continuous exercise v. intermittent exercise throughout the day) and meal consumption on glucose excursions, insulin secretion, and appetite markers in obese individuals with prediabetes. Methods: Eleven healthy, obese subjects (>30 kg/m2) with prediabetes underwent 3, 12 h study days including sedentary behavior (SED), exercise (EX; 1h morning exercise, 60-65% VO2 max), and physical activity (PA; 12 hourly, …

Functional Plasticity Of Central Trpv1 Receptors In Brainstem Dorsal Vagal Complex Circuits Of Streptozotocin-Treated Hyperglycemic Mice, Andrea Zsombok, Muthu D. Bhaskaran, Hong Gao, Andrei V. Derbenev, Bret N. Smith

Physiology Faculty Publications

Emerging data indicate that central neurons participate in diabetic processes by modulating autonomic output from neurons in the dorsal motor nucleus of the vagus (DMV). We tested the hypothesis that synaptic modulation by transient receptor potential vanilloid type 1 (TRPV1) receptors is reduced in the DMV in slices from a murine model of type 1 diabetes. The TRPV1 agonist capsaicin robustly enhanced glutamate release onto DMV neurons by acting at preterminal receptors in slices from intact mice, but failed to do so in slices from diabetic mice. TRPV1 receptor protein expression in the vagal complex was unaltered. Brief insulin preapplication …

The Effects Of Niacin And Aerobic Exercise In Postmenopausal Women Glucose, Insulin And C-Peptide Profiles, Heidi Bidstrup, Yunsuk Koh, James Rowe, David Nichols, Vic Ben-Ezra, Kyle Biggerstaff

International Journal of Exercise Science: Conference Proceedings

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Aerobic Capacity And Postprandial Flow Mediated Dilation, Kevin D. Ballard†, James J. Miller‡, James H. Robinson†, Jennifer L. Olive‡

International Journal of Exercise Science

The consumption of a high-fat meal induces transient vascular dysfunction. Aerobic exercise enhances vascular function in healthy individuals. Our purpose was to determine if different levels of aerobic capacity impact vascular function, as measured by flow mediated dilation, following a high-fat meal. Flow mediated dilation of the brachial artery was determined before, two- and four-hours postprandial a high-fat meal in young males classified as highly trained (n = 10; VO2max = 74.6 ± 5.2 ml·kg·min-1) or moderately active (n = 10; VO2max = 47.3 ± 7.1 ml·kg·min-1). Flow mediated dilation was reduced at two- (p < 0.001) and four-hours (p < 0.001) compared to baseline for both groups but was not different between groups at any time point (p = 0.108). Triglycerides and insulin increased at two- (p < 0.001) and four-hours (p < 0.05) in both groups. LDL-C was reduced at four-hours (p = 0.05) in highly trained subjects, and two- and four-hours (p ≤ 0.01) in moderately active subjects. HDL-C decreased at two- (p = 0.024) and four-hours (p = 0.014) in both groups. Glucose increased at two-hours postprandial for both groups (p = 0.003). Our results indicate that a high-fat meal results in reduced endothelium-dependent vasodilation in highly trained and moderately active individuals with no difference between groups. Thus, high aerobic capacity does not protect against transient reductions in vascular function after the ingestion of a single high-fat meal compared to individuals who are moderately active.

The Effect Of Intensity Of Aerobic Training On Insulin Sensitivity, Carmine Richard Grieco Iii

Human Movement Studies & Special Education Theses & Dissertations

Epidemiological studies have demonstrated that the prevalence of type 2 diabetes is increasing. It is estimated that I 0. 7% of adults over the age of 20 years and 23.1 % of adults over the age of 60 years have diabetes (NIH, 2007). Individuals with type 2 diabetes are 2-4 times more likely to die from heart disease than those without diabetes and twice as likely to die of all-cause mortality (CDC, 2005). Additionally Mokdad et al. (2000) report that the prevalence of diabetes increased 33% between 1990 and 1998. Furthermore it has been estimated that nearly 26% of the …

Role Of Lipolysis And Lipogenesis In The Development Of Diet-Induced Obesity, Michael John Davies

Theses and Dissertations in Biomedical Sciences

Obesity is an increasingly common public health problem with approximately one-half of the American adult population overweight and one-quarter considered obese. This alarming trend has led researchers to determine potential causative factors of excess weight gain in humans. However, it is difficult to discern whether perturbations that result in obesity are the cause or simply the result of the obese state. Diet-induced obesity is one of the animal models that allow researchers to address temporal issues. Our laboratory utilizes a diet-induced obesity model in which Sprague-Dawley rats are placed on a purified moderately high fat diet and ultimately diverge into …