The pineal secretory product melatonin was recently shown to have free radical scavenging properties. Melatonin also activates several antioxidative enzymes including glutathione (GSH) peroxidase, modulates gene expression for several protective enzymes and reduces lipid peroxidation. Additionally, the antioxidant effects of melatonin are probably based on its stimulatory effect on the expression of superoxide dismutase, GSH [...]