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 pro tein (HSP) 72] response in laboratory models of hypertrophy to natural ly occurring work-induced hypertrophy. Two laboratory models of hypert rophy inducement, namely, compensatory hypertrophy and stretch hypertr ophy, mere compared with hyper-trophy resulting from migratory flight in the blue-winged teal. We hypothesized that HSP 72 would be expresse d more strongly in hypertrophied muscle than in control muscle. Furthe rmore, we hypothesized that changes occurring in laboratory models wou ld also occur in work-induced enlargement. Sodium dodecyl sulfate-poly acrylamide gel electrophoresis and Western blot analyses were used to assess HSP 72 levels in control and hypertrophied muscle. Laboratory m odels elicited similar responses, with increased HSP 72 content in hyp ertrophied muscle. Work-induced hypertrophy or disuse atrophy did not change the degree of HSP 72 expression in the blue-winged teal. The pr esence of HSP 72 in these conditions may indicate that stressors elici ting changes in muscle protein expression, including the loss of muscl e mass, may elicit HSP 72 synthesis.