Heat treatment improves glucose tolerance and prevents skeletal muscle insulin resistance in rats fed a high-fat diet. Diabetes 58:567–578

OBJECTIVE—Heat treatment and overexpression of heat shock protein 72 (HSP72) have been shown to protect against high-fat diet–induced insulin resistance, but little is known about the underlying mechanism or the target tissue of HSP action. The purpose of this study is to determine whether in vivo heat treatment can prevent skeletal muscle insulin resistance. RESEARCH DESIGN AND METHODS—Male Wistar rats were fed a high-fat diet (60 % calories from fat) for 12 weeks and received a lower-body heat treatment (41°C for 20 min) once per week. RESULTS—Our results show that heat treatment shifts the metabolic characteristics of rats on a high-fat diet toward those on a standard diet. Heat treatment improved glucose tolerance, restored insulin-stimulated glucose transport, and increased in-sulin signaling in soleus and extensor digitorum longus (EDL