INDUCTION OF YA(1) SUBUNIT OF RAT HEPATIC GLUTATHIONE S-TRANSFERASES BY EXERCISE-INDUCED OXIDATIVE STRESS

Adult female rats subjected to exercise training in the form of swimmi ng daily (for 20 min initially with gradual increase up to 90 min with in a week) for 130 days showed a significant elevation of liver glutat hione S-transferase (GST) activity when compared to controls. Electrop horesis and Western blot analysis of cytosolic as well as affinity-pur ified hepatic glutathione S-transferases revealed the induction of Ya- sized subunit in exercise-trained animals. Reverse-phase HPLC analysis of affinity-purified GSTs further revealed that Ya-sized subunits in control animals consisted of predominantly Ya(2), whereas the trained animals displayed a dramatic 4.3-fold increase in Ya(1). The GSTs of e xercise-trained animals showed increased peroxidase activity when comp ared to corresponding controls, which is consistent with the changes i n subunit composition. This could be a response to the physiological o xidative stress induced by physical exercise. (C) 1995 Academic Press, Inc.