Effects of endurance training on superoxide dismutase activity, content and mRNA expression in rat muscle

Clin Exp Pharmacol Physiol. 1997 May;24(5):326-32. doi: 10.1111/j.1440-1681.1997.tb01196.x.


1. The purpose of the present study was to investigate the changes in superoxide dismutase (SOD) isoenzyme (Mn(2+)-SOD and Cu2+, Zn(2+)-SOD) activities, contents and mRNA expressions in rat skeletal muscle during endurance training and a single bout of exercise. 2. Thirty-eight male Wistar rats were divided into untrained (U) and trained (T) groups. The T group rats were treadmill-trained for 9 weeks. The activity, content and mRNA expression of Mn(2+)-SOD and Cu2+, Zn(2+)-SOD were determined in the soleus muscle of each rat. 3. Mn(2+)-SOD activity and content in the T group were significantly higher than in the U group, both at rest (22 and 21%, respectively) and after exercise (24 and 46%, respectively), while a single bout of exercise affected neither the activity nor content of Mn(2+)-SOD in either group. 4. The content of Cu2+,Zn(2+)-SOD in both groups was not different at rest and after exercise, although its activity at rest was significantly higher in the T group than in the U group (by 29%). 5. After exercise, the expression of Mn(2+)-SOD mRNA was markedly attenuated only in the U group (49%); the expression of Cu2+,Zn(2+)-SOD mRNA was not influenced by exercise. 6. Our results suggest that adequate endurance training increases both the activity and content of Mn(2+)-SOD and that untrained rats are rather susceptible to oxidative stress during physical exercise. It thus appears that Mn(2+)-SOD provides a reliable index of physical training. 7. The results obtained in the present study also suggest that muscle has the capacity of responding to training in such a manner as to reduce the potential harm arising from the accumulation of oxygen free radicals resulting from enhanced metabolic activity.

MeSH terms

  • Animals
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Male
  • Muscle, Skeletal / enzymology*
  • Muscle, Skeletal / physiology
  • Oxidative Stress / physiology
  • Physical Conditioning, Animal / physiology*
  • RNA, Messenger / biosynthesis*
  • Rats
  • Rats, Wistar
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism*


  • Isoenzymes
  • RNA, Messenger
  • Superoxide Dismutase