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- Title
Effect of acute exercise on AMPK signaling in skeletal muscle of subjects with type 2 diabetes: a time-course and dose-response study.
- Authors
Sriwijitkamol, Apiradee; Coletta, Dawn K; Wajcberg, Estela; Balbontin, Gabriela B; Reyna, Sara M; Barrientes, John; Eagan, Phyllis A; Jenkinson, Christopher P; Cersosimo, Eugenio; DeFronzo, Ralph A; Sakamoto, Kei; Musi, Nicolas
- Abstract
Activation of AMP-activated protein kinase (AMPK) by exercise induces several cellular processes in muscle. Exercise activation of AMPK is unaffected in lean (BMI approximately 25 kg/m(2)) subjects with type 2 diabetes. However, most type 2 diabetic subjects are obese (BMI >30 kg/m(2)), and exercise stimulation of AMPK is blunted in obese rodents. We examined whether obese type 2 diabetic subjects have impaired exercise stimulation of AMPK, at different signaling levels, spanning from the upstream kinase, LKB1, to the putative AMPK targets, AS160 and peroxisome proliferator-activated receptor coactivator (PGC)-1alpha, involved in glucose transport regulation and mitochondrial biogenesis, respectively. Twelve type 2 diabetic, eight obese, and eight lean subjects exercised on a cycle ergometer for 40 min. Muscle biopsies were done before, during, and after exercise. Subjects underwent this protocol on two occasions, at low (50% Vo(2max)) and moderate (70% Vo(2max)) intensities, with a 4-6 week interval. Exercise had no effect on LKB1 activity. Exercise had a time- and intensity-dependent effect to increase AMPK activity and AS160 phosphorylation. Obese and type 2 diabetic subjects had attenuated exercise-stimulated AMPK activity and AS160 phosphorylation. Type 2 diabetic subjects had reduced basal PGC-1 gene expression but normal exercise-induced increases in PGC-1 expression. Our findings suggest that obese type 2 diabetic subjects may need to exercise at higher intensity to stimulate the AMPK-AS160 axis to the same level as lean subjects.
- Publication
Diabetes, 2007, Vol 56, Issue 3, p836
- ISSN
0012-1797
- Publication type
Journal Article
- DOI
10.2337/db06-1119