Redox balance and mitochondrial glycerol phosphate dehydrogenase activity in trained rats

Free radical production is increased in many disease states and during exercise, but in the latter the concurrent stimulation of the antioxidant defense system seems to protect the organism from excessive production of reactive oxygen species. Chronic exercise can exert negative effects on the activity of mitochondrial glycerol phosphate dehydrogenase (mGPdH), which may offer some explanation for the antioxidant effects of training, since this enzyme is a relevant producer of free radicals. To test this correlation, we compared mGPdH activity, two antioxidant defense markers and two markers of oxidative stress in sedentary and trained (Tr) rats. Training was through a swimming exercise 3 days a week. After 8 weeks, Tr rats lasted twice as long as controls in an acute swimming test with a 5% load. Forty-eight hours after the last exercise, the animals were killed to collect blood and tissues. Tr animals presented lower body weight and visceral fat mass with lower triglyceride content in visceral fat and plasma ( p