A pyrimidine derivative, widely used for the induction of diabetes in experimental animals. It preferentially accumulates in pancreatic β cells in Langerhans islets via glucose transporter GLUT2. In the presence of intracellular thiols such as glutathione, it gets involved in a cyclic redox reaction with its reduction product, dialuric acid. This triggers the production of toxic levels of reactive oxygen species (ROS) and directs the cells in necrosis. Alloxan also inhibits glucokinase, which regulates glucose-induced insulin secretion.