[Relationship between toxic effects of potassium bromate and endocrine glands].

Potassium bromate (KBrO(3)) is a compound belonging to Group 2B of carcinogens (a possible human carcinogen). This agent was used as a food additive in flour treatment, as a component of cold-wave hair lotions, and is still used in barley processing. Additionally, KBrO(3) is formed as an oxyhalide by-product during water ozonation. KBrO(3) induces oxidative stress and may contribute to neoplasia in endocrine glands. It has been demonstrated that KBrO(3) triggers thyroid follicular cell tumors in rats. It has been revealed in our in vivo and in vitro studies that KBrO(3) significantly increases lipid peroxidation in rat and porcine thyroid. KBrO(3) also induces mesotheliomas which may secrete hormones or similar substances, such as parathyroid hormone related protein, phosphatonins or melanocyte stimulating hormone. In our experimental studies we demonstrated that antioxidants, such as pineal hormone - melatonin, indole-3-propionic acid (IPA) (a compound chemically and physically similar to melatonin) and antythyroid drug - propylthiouracil (PTU), produce distinct protective effects against lipid peroxidation due to KBrO(3) in the thyroid in vivo. KBrO(3) is a prooxidant which may induce neoplasia in endocrine glands and cause hormonal disturbances, however its damaging effects may be neutralized by hormones, mainly melatonin.