The increased iNOS staining observed in the islets of PBS-treated db/db mice may also contribute to β-cell dysfunction as iNOS-derived nitric oxide inhibits insulin secretion from β-cells in vitro[20] and, furthermore, iNOS inhibitors ameliorate β-cell dysfunction in rodent models of type 2 diabetes [13]. The gene discussed is NOS2; the disease is type 2 diabetes mellitus.