UCP1 and diabetes mellitus: Additionally, Goto-Kakizaki rats (a nonobese model of type 2 diabetes mellitus) exhibit lower plasma levels of KYNA as compared to the wild type; oral administration of KYNA delays the development of diabetes in Goto-Kakizaki rats and stimulates the expression of uncoupling protein (UCP) in HepG2 cells and mouse hepatocytes at mRNA and protein levels [234].