HSP72 gene expression progressively increases in human skeletal muscle during prolonged, exhaustive exercise

1 Exercise Physiology and Metabolism Laboratory, Department of Physiology, and 2 Howard Florey Institute of Experimental Physiology and Medicine, The University of Melbourne, Parkville, Victoria 3052, Australia To examine the effect of exercise on heat shock protein (HSP) 72 mRNA expression in skeletal muscle, five healthy humans (20 ± 1 yr; 64 ± 3 kg; peak O 2 uptake of 2.55 ± 0.2 l/min) cycled until exhaustion at a workload corresponding to 63% peak O 2 uptake. Muscle was sampled from the vastus lateralis, and muscle temperature was measured at rest (R), 10 min of exercise (Min10), ~40 min before fatigue (F-40 = 144 ± 7 min), and fatigue (F = 186 ± 15 min). Muscle samples were analyzed for HSP72 mRNA expression, as well as glycogen and lactate concentration. Muscle temperature increased ( P