The oxidative stress which is caused by free radicals can play role in emerging and/or progressing many diseases. Hyperthyroidism can induce a lot of changes dealing with the systems of nitric oxide (NO) and antioxidant systems of several tissues in increasing the production of free radicals. The aim of this study is to investigate the changes of NO, malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase (GSH-Px) in the hyperthyroidic patients who have been treated with propylthiouracil (PTU).
Materials and Methods: According to this aim the NO, MDA, GSH and GSH-Px levels are determined in the just diagnosed 21 patients before and after PTU treatment. Same parameters were investigated in the control group consisting of 20 healthy individuals.
Results: While the free triiodothyronine (FT3), free thyroxine (FT4), NO, MDA levels of patient group before PTU treatment were found to be significantly higher than those of control group (Student's T test, p<0.001), GSH levels were found to be lower (Student's T test, p<0.05). Patient group's GSH-Px and GSH levels after PTU treatment were found to be higher than those before treatment and NO and MDA levels were found to be lower after treatment (Student's T test, respectively p<0.005, p<0.001, p<0.005, p<0.005).
When the FT3 and GSH-Px levels of patients after treatment were compared with those of control group, it has been found out, that GSH-Px levels of patients have increased and FT3 levels were still higher than those of control group (Student's T test, both p<0,001). After PTU therapy, the FT4, NO and MDA levels of patient group were not significantly different from those of control group (Student's T test, p>0.05), and GSH levels were still lower (Student's T test, p<0.001).
Conclusion: The findings of our study has shown that hyperthyroidism deteriorates the balance in the oxidant-antioxidant system in favour of oxidants. PTU therapy tries to correct this. The changes of NO during these interactions let us consider that NO is related to the pathophysiology and possibly to the therapy of the disease.