title: Effects of endurance training on superoxide dismutase activity, content and mRNA expression in rat muscle.
abstract: 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.
authors.affiliation: Department of Hygiene, National Defense Medical College, Tokorozawa, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Oh-ishi
authors.forename: T
authors.initials: T
authors.lastname: Kizaki
authors.forename: J
authors.initials: J
authors.lastname: Nagasawa
authors.forename: T
authors.initials: T
authors.lastname: Izawa
authors.forename: T
authors.initials: T
authors.lastname: Komabayashi
authors.forename: N
authors.initials: N
authors.lastname: Nagata
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: N
authors.initials: N
authors.lastname: Taniguchi
authors.forename: H
authors.initials: H
authors.lastname: Ohno
mesh_terms: D000818:Animals; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000502:physiology; D018384:Oxidative Stress / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D013482:Superoxide Dismutase