Effect of vitamin E deprivation and exercise training on induction of HSP70

To investigate the effect of dietary vitamin E deprivation and chronic exercise on the relative content of selected isoforms of the heat-shock protein 70 (HSP70) family in rat hindlimb muscle, vitamin E was withheld for 16 wk from female rats that underwent treadmill run training during the final 8 wk. As indicated by increased (P < 0.05) content of the stress-inducible isoform (HSP72), training did stress the exercising muscles. However, vitamin E deficiency did not alter HSP72 content in nontrained rats and was associated with a lesser induction (P < 0.01) in some muscles of trained animals. The constitutive isoform, which exhibited similar levels in muscles of varying fiber types, was demonstrated to be largely refractory to exercise, with an equivocal response to vitamin E deprivation. HSP72 content was correlated to type I myosin heavy chain (MHC-I) content but only in muscles of sedentary normal-diet rats. After training, HSP72 content in a muscle essentially devoid of MHC-I (superficial vastus lateralis) reached levels comparable to those in a muscle high in MHC-I (soleus).