Injection of streptozotocin (STZ) in one of the animal models produces diabetes (types I and II diabetes mellitus) by destroying pancreatic β-cells, probably via a free radical mechanism.[19] The purpose of this study was to investigate the effects of P. persica methanol extract (PPE) on STZ-induced diabetes in rats, by measuring fasting blood glucose, insulin levels, total antioxidant power (TAP), and hepatocellular lipid peroxidation, and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). The gene discussed is INS; the disease is diabetes mellitus.