SUMMARY
Strenuous exercise increases oxygen consumption and causes disturbance of intracellular pro-oxidant–antioxidant homeostasis. Ghrelin has been reported to possess free radical scavenging and antioxidant effect. in this study we aim to evaluate the beneficial effect of ghrelin on the oxidative stress and antioxidant enzyme systems in brain cortex and liver of rats after exhaustive swimming exercise. Sprague- Dawley rats (50) were subdivided into 3 main groups: control, exercise, exercise and ghrelin (50,100,200 ng) group. Animals in the two exercise groups swam for 5 days/week for 4 weeks. stress induced a decrease in the level of GSH and the activities of SOD, GST and catalase, while the levels of TBARS were found elevated. Ghrelin groups’ animals, especially G3 subgroup, have higher SOD, CAT, GSH and GST activity which reflect higher antioxidant enzyme activity and can be attributed to lower rates of oxidative stress which can be proved by reduced level of TBARS. The results of the study provides evidence that ghrelin pretreatment even in low dose reduces the level of lipid peroxidation and enhances the antioxidant defense against exercise-induced stress oxidative injury in rats’ vital organs like brain and liver.