Aim: The aim of the present study was to test the hypothesis that interleukin-6 plays a role in exercise-induced PGC-1a and TNFa mRNA responses in skeletal muscle and to examine the potential IL-6 mediated AMPK regulation in these responses. Methods: Whole body IL-6 knockout and wildtype (WT) male mice (4 month) performed 1h treadmill exercise. White gastrocnemius (WG) and quadriceps muscles were removed immediately (0') or 4h after exercise and from mice not run acutely. Results: Acute exercise reduced only in WT muscle glycogen concentration to 55% and 35% (P