Document Type

Thesis

Abstract

Phosphorylase kinase (PhK), a key regulator of glycogenolysis, is critical for maintaining blood glucose levels thus providing energy to sustain muscle contraction. A deficiency of PhK in skeletal muscle is the cause of one type of glycogen storage disease (GSD) in humans. This study investigates the physiological and genetic adaptations that occur in a mouse model of GSD, I/LnJ mice, in response to voluntary exercise. Juvenile (6-8 weeks old) and adult (12-14 weeks old) I/LnJ and wild-type C57/Bl6 mice exercised voluntarily for 1, 2 or 5 weeks. Exercise data was calculated as mean daily running time, daily running distance, total running time, total running distance, and average speed. After five weeks, adult and juvenile I/LnJ mice were running 45-70% of the daily distance of age-matched, wild-type mice. A training effect was observed in wild-type mice during the five week exercise period, but no significant difference was observed in heart/body weight ratios in exercised mice compared to non-exercised controls. Expression levels of glucose transporter 4 (GLUT4), pyruvate dehydrogenase (PDHA1), and phosphofructokinase (PFKM) as a result of exercise were determined by quantitative RT-PCR in both I/LnJ and ii C57/Bl6 mice. No significant differences in expression levels were found between mouse strains. Our long term goal is to gain insights into the I/LnJ strain’s PhK deficiency in order to better understand human GSDs.

Advisor(s) or Committee Chair

Dr. Nancy Rice

Disciplines

Physical Sciences and Mathematics