Original Article Effect of Acute Exercise on AMPK Signaling in Skeletal Muscle of Subjects With Type 2 Diabetes A Time-Course and Dose-Response Study

Activation of AMP-activated protein kinase (AMPK) by exercise induces several cellular processes in muscle. Ex-ercise activation of AMPK is unaffected in lean (BMI 25 kg/m2) subjects with type 2 diabetes. However, most type 2 diabetic subjects are obese (BMI>30 kg/m2), 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 signal-ing levels, spanning from the upstream kinase, LKB1, to the putative AMPK targets, AS160 and peroxisome prolifera-tor–activated receptor coactivator (PGC)-1, 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 exer