The heat map analysis of selected genes, which were previously linked with β-cell functions or diabetes, further demonstrated STZ-mediated suppression of a wide range of β-cell-and/or diabetes-related genes, including Slc30a8, Neurod1, Nkx6.1, Isl1, Foxa2 (Hnf3b), Pax6, Pdx1, Fkbp1b, Prkca, Dpp4, Abcc8 and Foxo1 (Fig. 5D). Here, ISL1 is linked to diabetes mellitus.