Exercise maintains euglycemia in association with decreased activation of c-Jun NH2-terminal kinase and serine phosphorylation of IRS-1 in the liver of ZDF rats.
Stress-activated systems and oxidative stress are involved in insulin resistance, which, along with beta-cell failure, contribute to the development of type 2 diabetes mellitus (T2DM). Exercise improves insulin resistance and glucose tolerance, and these adaptations may, in part, be related to reductions in inflammation and oxidative stress. We investigated circulating and tissue-specific markers of inflammation and oxidative stress and insulin-signaling pathways in a rodent model of T2DM, the Zucker diabetic fatty rat, with and without voluntary exercise. At 5 wk of age, Zucker diabetic fatty rats (n = 8-9/group) were divided into basal (B), voluntary exercise (E), and sedentary control (S) groups. B rats were euthanized at 6 wk of age, and S and E rats were euthanized 10 wk later. E rats ran approximately 5 km/day, which improved insulin sensitivity and maintained fed and fasted glucose levels and glucose tolerance. Ten weeks of exercise also decreased whole body markers of inflammation and oxidative stress in plasma and liver, including lowered circulating IL-6, haptoglobin, and malondialdehyde levels, hepatic protein oxidation, and phosphorylated JNK, the latter indicating decreased JNK activity. Hepatic phosphoenolpyruvate carboxykinase levels and Ser(307)-phosphorylated insulin receptor substrate-1 were also reduced in E compared with S rats. In summary, we show that, in a rodent model of T2DM, voluntary exercise decreases circulating markers of inflammation and oxidative stress and lowers hepatic JNK activation and Ser(307)-phosphorylated insulin receptor substrate-1. These changes in oxidative stress markers and inflammation are associated with decreased hyperglycemia and insulin resistance and reduced expression of the main gluconeogenic enzyme phosphoenolpyruvate carboxykinase.
Király
Michael A
MA
Dept. of Physiology, Univ. of Toronto, ON, Canada.
Campbell
Jon
J
Park
Edward
E
Bates
Holly E
HE
Yue
Jessica T Y
JT
Rao
Venket
V
Matthews
Stephen G
SG
Bikopoulos
George
G
Rozakis-Adcock
Maria
M
Giacca
Adria
A
Vranic
Mladen
M
Riddell
Michael C
MC
D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000517:prevention & control*; D004195:Disease Models, Animal; D004789:Enzyme Activation; D005081:Exercise Therapy / Q000379:methods*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress; D010766:Phosphorylation; D010805:Physical Conditioning, Animal / Q000379:methods; D051381:Rats; D011924:Rats, Zucker; D012694:Serine / Q000378:metabolism
D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; D012694:Serine; D048031:JNK Mitogen-Activated Protein Kinases; D005947:Glucose