ABSTRACT
This study was performed to explore the effect of vitamin A administration on Free Radicals production and antioxidant system activity and lactate levels in individuals exercised to exhaustion The study registered 10 healthy sedentary males their mean age was 22,85+/-0,26 years. The subjects were orally administrated with 300 mg vitamin A [retinol] for 4 weeks and engaged in strenuous exercise [using the Bruce protocol] once a week. Blood samples were collected from the subjects at four different times, before and after the supplementation and before and after exercise to analyze Malondialdehyde [MDA], Nitric oxide [NO], Glutathione [GSH], Glutathione peroxidase [GSH-Px], Catalase [CAT], Superoxide dismutase [SOD] levels using colorimetric ELISA test kits and plasma lactate levels using an autoanalyzer. Exhaustion exercise leaded to an increase in both MDA, NO, and lactate, and GSH, GSH-Px, CAT and SOD levels compared to resting levels both before and after supplementation [p<0.05]. Increased NO levels found in pre-supplementation exhaustion showed a significant decrease after the supplementation of vitamin A [p<0.05], but the other parameters were not changed after vitamin A administration. The results of our study demonstrate that the increase caused by 4-week strenuous exercise in the levels of the free radical NO was offset by vitamin A supplementation. It can be suggested that supplementation of vitamin A at physiological doses has a limited effect on lipid peroxidation caused by strenuous exercise