Increased postexercise insulin sensitivity is accompanied by increased AS160 phosphorylation in slow‐twitch soleus muscle

• Published in: Physiological reports Vol. 2; no. 12; pp. e12162 - n/a
• Main Authors: Iwabe, Maiko, Kawamoto, Emi, Koshinaka, Keiichi, Kawanaka, Kentaro
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.12.2014; Wiley Periodicals, Inc
• Subjects: AKT protein; Animals; AS160; exercise; Fitness equipment; Glucose; glucose uptake; Insulin; insulin sensitivity; Kinases; Musculoskeletal system; Original Research; Phosphorylation; Physiology; Proteins; Rodents; Skeletal muscle; slow‐twitch muscle; Soleus muscle; Studies; TBC1D1; slow‐twitch muscle; TBC1D1; insulin sensitivity; exercise; AS160; glucose uptake
• ISSN: 2051-817X; 2051-817X
• DOI: 10.14814/phy2.12162

A single bout of exercise can enhance insulin‐stimulated glucose uptake in both fast‐twitch (type II) and slow‐twitch (type I) skeletal muscle for several hours postexercise. Akt substrate of 160 kDa (AS160) is most distal insulin signaling proteins that have been proposed to contribute to the postexercise enhancement of insulin action in fast‐twitch muscle. In this study, we examined whether the postexercise increase in insulin action of glucose uptake in slow‐twitch muscle is accompanied by increased phosphorylation of AS160 and its paralog TBC1D1. Male Wistar rats (~1‐month‐old) were exercised on a treadmill for 180 min (9 m/min). Insulin (50 μU/mL)‐stimulated glucose uptake was increased at 2 h after cessation of exercise in soleus muscle composed of predominantly slow‐twitch fibers. This postexercise increase in insulin action of glucose uptake was accompanied by increased phosphorylation of AS160 (detected by phospho‐Thr642 and phospho‐Ser588 antibody). On the other hand, prior exercise did not increase phosphorylation of TBC1D1 (detected by phospho‐Thr590) at 2 h postexercise. These results suggest the possibility that an enhancement in AS160 phosphorylation but not TBC1D1 phosphorylation is involved with increased postexercise insulin action of glucose uptake in slow‐twitch muscle. e12162 In slow‐twitch soleus muscle, phosphorylation of AS160 Thr642 and Ser588 was increased together with the enhanced insulin action of the glucose uptake at 2 h postexercise. The phosphosite of TBC1D1 (Thr590), which is possibly important for insulin‐stimulated glucose uptake, did not increase phosphorylation at 2 h postexercise. These results suggest that the increased phosphorylation of AS160, but not TBC1D1, can account for the postexercise enhancement in the insulin action of the glucose uptake in slow‐twitch muscle.