Stress protein induction in skeletal muscle: comparison of laboratory models to naturally occurring hypertrophy

The purpose of the study was to compare stress protein [heat shock protein (HSP) 72] response in laboratory models of hypertrophy to naturally occurring work-induced hypertrophy. Two laboratory models of hypertrophy inducement, namely, compensatory hypertrophy and stretch hypertrophy, were compared with hypertrophy resulting from migratory flight in the blue-winged teal. We hypothesized that HSP 72 would be expressed more strongly in hypertrophied muscle than in control muscle. Furthermore, we hypothesized that changes occurring in laboratory models would also occur in work-induced enlargement. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses were used to assess HSP 72 levels in control and hypertrophied muscle. Laboratory models elicited similar responses, with increased HSP 72 content in hypertrophied muscle. Work-induced hypertrophy or disuse atrophy did not change the degree of HSP 72 expression in the blue-winged teal. The presence of HSP 72 in these conditions may indicate that stressors eliciting changes in muscle protein expression, including the loss of muscle mass, may elicit HSP 72 synthesis.