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Australian Catholic University

Skeletal muscle

Medical Sciences

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Full-Text Articles in Medicine and Health Sciences

No Evidence Of Direct Association Between Glut4 And Glycogen In Human Skeletal Muscle, Robyn M. Murphy, Marcelo Flores-Opazo, Barnaby P. Frankish, Andrew Garnham, David Stapleton, Mark Hargreaves Jan 2018

No Evidence Of Direct Association Between Glut4 And Glycogen In Human Skeletal Muscle, Robyn M. Murphy, Marcelo Flores-Opazo, Barnaby P. Frankish, Andrew Garnham, David Stapleton, Mark Hargreaves

Faculty of Health Sciences Publications

Previous studies have demonstrated that exercise increases whole body and skeletal muscle insulin sensitivity that is linked with increased GLUT4 at the plasma membrane following insulin stimulation and associated with muscle glycogen depletion. To assess the potential direct association between muscle glycogen and GLUT4, seven untrained, male subjects exercised for 60 min at ~75% VO2 peak, with muscle samples obtained by percutaneous needle biopsy immediately before and after exercise. Exercise reduced muscle glycogen content by ~43%. An ultracentrifugation protocol resulted in a ~2‐3‐fold enriched glycogen fraction from muscle samples for analysis. Total GLUT4 content was unaltered by exercise ...


Interactive Roles For Ampk And Glycogen From Cellular Energy Sensing To Exercise Metabolism, Natalie Janzen, Jamie Whitfield, Nolan Hoffman Jan 2018

Interactive Roles For Ampk And Glycogen From Cellular Energy Sensing To Exercise Metabolism, Natalie Janzen, Jamie Whitfield, Nolan Hoffman

Faculty of Health Sciences Publications

The AMP-activated protein kinase (AMPK) is a heterotrimeric complex with central roles in cellular energy sensing and the regulation of metabolism and exercise adaptations. AMPK regulatory β subunits contain a conserved carbohydrate-binding module (CBM) that binds glycogen, the major tissue storage form of glucose. Research over the past two decades has revealed that the regulation of AMPK is impacted by glycogen availability, and glycogen storage dynamics are concurrently regulated by AMPK activity. This growing body of research has uncovered new evidence of physical and functional interactive roles for AMPK and glycogen ranging from cellular energy sensing to the regulation of ...


A Novel In Vitro Model For The Assessment Of Postnatal Myonuclear Accretion, Anita Kneppers, Lex B. Verdijk, Chiel De Theije, Mark Corten, Ellis Gielen, Luc Van Loon, Annemie Schols, Ramon Langen Jan 2018

A Novel In Vitro Model For The Assessment Of Postnatal Myonuclear Accretion, Anita Kneppers, Lex B. Verdijk, Chiel De Theije, Mark Corten, Ellis Gielen, Luc Van Loon, Annemie Schols, Ramon Langen

Faculty of Health Sciences Publications

Background: Due to the post-mitotic nature of myonuclei, postnatal myogenesis is essential for skeletal muscle growth, repair, and regeneration. This process is facilitated by satellite cells through proliferation, differentiation, and subsequent fusion with a pre-existing muscle fiber (i.e., myonuclear accretion). Current knowledge of myogenesis is primarily based on the in vitro formation of syncytia from myoblasts, which represents aspects of developmental myogenesis, but may incompletely portray postnatal myogenesis. Therefore, we aimed to develop an in vitro model that better reflects postnatal myogenesis, to study the cell intrinsic and extrinsic processes and signaling involved in the regulation of postnatal myogenesis ...


Autophagy And Protein Turnover Responses To Exercise-Nutrient Interactions In Human Skeletal Muscle, William J. Smiles Jun 2017

Autophagy And Protein Turnover Responses To Exercise-Nutrient Interactions In Human Skeletal Muscle, William J. Smiles

Theses

Skeletal muscle is a dynamic tissue comprising the largest protein reservoir of the human body with a rate of turnover of ~1-2% per day. Protein turnover is regulated by the coordination of intracellular systems regulating protein synthesis and breakdown that converge in a spatiotemporal manner on lysosomal organelles responsible for integrating a variety of contractile and nutritional stimuli. One such system, autophagy, which literally means to ‘self-eat,’ involves capturing of cellular material for deliver to, and disintegration by, the lysosome. The autophagic ‘cargo’ is subsequently recycled for use in synthetic reactions and thus maintenance of protein balance. As a dynamic ...


Skeletal Muscle Ampk Is Essential For The Maintenance Of Fndc5 Expression, James S. V. Lally, Rebecca J. Ford, Jasper Johar, Justin D. Crane, Bruce Ernest Kemp, Gregory R. Steinberg Jan 2015

Skeletal Muscle Ampk Is Essential For The Maintenance Of Fndc5 Expression, James S. V. Lally, Rebecca J. Ford, Jasper Johar, Justin D. Crane, Bruce Ernest Kemp, Gregory R. Steinberg

Faculty of Health Sciences Publications

Fibronectin type III domain‐containing protein 5 (FNDC5) expression is controlled by the transcriptional co‐activator, peroxisome proliferator‐activated receptor gamma, coactivator 1 alpha (PGC1α). FNDC5 expression has been shown to be increased in muscle in response to endurance exercise in some but not all studies, therefore a greater understanding of the mechanisms controlling this process are needed. The AMP‐activated protein kinase (AMPK) is activated by exercise in an intensity dependent manner and is an important regulator of PGC1α activity; therefore, we explored the role of AMPK in the regulation of FNDC5 using AMPK β1β2 double muscle‐null mice ...