My interests in skeletal muscle metabolism and physiology were kindled as an undergraduate research assistant. I completed my Masters and Doctoral degrees at the University of Guelph, studying the mechanisms underlying the interaction between fat and carbohydrate utilization in contracting skeletal muscle. I then began my NSERC-funded postdoctoral fellowship at the University of Waterloo. During this tenure, I learned novel techniques for studying fat transport, and its metabolic fates in isolated skeletal muscle. I have continued to study muscle lipid metabolism since taking up my faculty position at Guelph in July 1998. My interests involve the hormonal regulation of muscle lipid metabolism, and in particular its’ dysfunction in the development of insulin resistance and diabetes. I currently have memberships in the Canadian and American Physiological Societies
B.Sc. - University of Guelph M.Sc. - University of Guelph Ph.D. - University of Guelph
My interests lie in the regulation of fat and carbohydrate metabolism in skeletal muscle, with a particular emphasis on the dysregulation that occurs in obesity and diabetes. Several cytokines released from skeletal muscle, including leptin and adiponectin, are known to significantly affect insulin response in peripheral tissues such as muscle. My research has focused on the effects of these adipokines on muscle lipid and carbohydrate metabolism, and particularly, how the muscle becomes resistant to their effects in obese models and with high fat feeding. The interaction of diet and exercise is also a point of interest in terms of the muscle's response to various hormones including insulin, leptin and adiponectin.
Ritchie IW, MacDonald T, Wright DC,
. Adiponectin is sufficient, but not required, for exercise-induced increases in the expression of skeletal muscle mitochondrial enzymes. J Physiol. Accepted March 26, 2014.
Tishinsky JM, De Boer AA,
, Robinson LE. Modulation of visceral fat adipokine secretion by dietary fatty acids and ensuring changes in skeletal muscle inflammation. Appl Physiol Nutr Metab. 2014; 39(1):28-37.
Macdonald TL, Wan Z, Frendo-Cumbo S,
, Wright DC. IL-6 and epinephrine have divergent fiber type effects on intramuscular lipolysis. J Appl Physiol. 2013; 115(10):1457-63.
Stefanyk LE, Bonen A, Dyck DJ. Fatty acid transport proteins chronically relocate to the transverse-tubules in muscle from obese Zucker rats but are resistant to further insulin-induced translocation. Metabolism. 2013; 62(9):1296-304.
Gulli RA, Tishinsky JM, MacDonald T, Robinson LE, Wright DC,
. Exercise restores insulin, but not adiponectin, response in skeletal muscle of high-fat fed rodents. Am J Physiol Regul Integr Comp Physiol. 2012; 303(10):R1062-70.
Tishinsky JM, Robinson LE,
. Insulin-sensitizing properties of adiponection. Biochimie. 2012; 94(10):2131-6.
Stefanyk L, Bonen A,
. Insulin and contraction-induced movement of fatty acid transport proteins to skeletal muscle transverse-tubules is distinctly different than to the sarcolemma. Metabolism. 2012; 61(11):1518-22.
Tishinsky J, Gulli R, Mullen K,
, Robinson L. Fish oil prevents high saturated fat diet-induced impairments in adiponectin and insulin response in rodent skeletal muscle. Am J Physiol. 2012; 302:R598-605.
Stefanyk L, Gulli R, Ritchie I, Chabowski A, Snook L,
. Recovered insulin response by 2 weeks of leptin administration is associated with restored AS160 activation and decreased reactive lipids. Am J Physiol. 2011; 301:R159-71.
Thrush AB, Harasim E, Chabowski A, Gulli R, Stefanyk L,
. A single prior bout of exercise protects against palmitate-induced insulin resistance despite an increase in total ceramide content. Am J Physiol. 2011; 300:R1200-8.
Ritchie I, Gulli R, Stefanyk L, Harasim E, Chabowski A,
. Restoration of skeletal muscle leptin response does not precede the exercise-induced recovery of insulin stimulated glucose uptake in high-fat fed rats. Am J Physiol. 2011; 300:R492-500.
Mullen K, Tishinsky J, Robinson L, and
. Skeletal muscle inflammation is not responsible for the rapid impairment in adiponectin response with high fat feeding in rats. Am J Physiol. 2010; 299:R500-8.
Cresser J, Bonen A, Chabowski A, Stefanyk LE, Gulli R, Ritchie I,
. Oral administration of a PPAR-delta agonist to rodents worsens, not improves, maximal insulin-stimulated glucose transport in skeletal muscle of different fibers. Am J Physiol. 2010; 299:R470-9.
Thrush AB, Brindley DN, Chabowski A, Heigenhauser GJ,
. Skeletal muscle lipogenic protein expression is not different between lean and obese humans: a potential factor in ceramide accumulation. J Clin Endo Metab. 2009; 94(12):5053-61.
Mullen K, Pritchard J, Ritchie I, Snook L, Chabowski A, Bonen A, Wright D,
. Adiponectin resistance precedes the accumulation of skeletal muscle lipids and insulin resistance in high fat fed rats. Am J Physiol. 2009; 296: R243-51.
, Heigenhauser GJF, Bruce CR. The role of adipokines as regulators of skeletal muscle fatty acide metabolism and insulin sensitivity. Acta Physiologica. 2006; 186:5-16.
Collier CA, Bruce CR, Smith AC, Lopaschuk G,
. Metformin counters the insulin-induced suppression of fatty acid oxidation and stimulation of triacylglyerol storage in rodent skeletal muscle. Am J Physiol. 2006; 291:E182-9.
Bruce CR, Mertz V, Heigenhauser GJF,
. The stimulatory effect of globular adiponectin on insulin-stimulated glucose uptake and fatty acid oxidation is impaired in skeletal muscle from obese subjects. Diabetes. 2005; 54(11):3154-60.
BIOL*1080 Biological Concepts of Health
HK*4230 Advanced Study in Human Biology & Nutritional Sciences
HK*4360 Research in Human Biology & Nutritional Sciences
HK*4371/2 Research in Human Biology & Nutritional Sciences