Because UCP2 was reported to be increased in islets from T2DM donors (Anello et al., 2005), we measured Ucp2 expression in islets from insulin receptor substrate (Irs)-2-deficient (IRS2KO) mice (Kubota et al., 2000) and BKS.Cg-Dock7m+/+Leprdb/J (db/db) mice, which are models of T2DM that exhibit both β-cell dysfunction and insulin resistance. The gene discussed is INS; the disease is type 2 diabetes mellitus.