LEPR and type 2 diabetes mellitus: Type 2 diabetes can also be produced in rodents by utilizing monogenic mutations (Lep ob/ob (ob/ob) mice, Lepr db/db (db/db) mice, Zucker diabetic fatty (ZDF-Lepr fa/fa or fa/fa) rats), or polygenic mutations (Kuo Kondo (KK) mice, Otsuka Long-Evans Tokushima Fat (OLEFT) rats, etc.).