| Acute and endurance exercise has previously been shown to induce a stress response. The aim of this project was to investigate the HSP70 response to acute and chronic exercise, among several inbred strains of rats, and selectively bred rats. Peripheral skeletal muscles dramatically increased (p<0.05) their HSP synthesis after an acute high intensity bout of exercise for only the untrained runners. However, increased training intensity was relatively proportional to increased HSP70's inducible isoform (HSP70i) content, demonstrating that trained animals adapt to the stress of prolonged training stress by increasing their HSP70i content levels. Rats artificially selected for low (LCR) or high (HCR) intrinsic aerobic capacity demonstrated no significant changes in HSP70i content for any tissues in either the founder population (G0) or the third generation (G3). However, at generation 10 (G10), there was a significant difference between sedentary LCR and HCR rats HSP70i content (p<0.05) as well as a significant increase from the sedentary G0 rats to sedentary G10 HCR. Furthermore, artificial selection has displayed a separation in aerobic endurance performance correlated with an equivalent segregation of HSP70i content in sedentary rats. Among three different rat strains with differing aerobic exercise capabilities, their final exercise performance correlated with HSP70i content while their sedentary levels did not. Data from these studies support HSP70i as having an influencing role in aerobic exercise performance and provides evidence that one set of genes may dictate the initial exercise performance level and another set of genes the response to training. |
