DIMT1 deficiency and its impact on insulin secretion. Insulin secretion, 72 h after of siRNA transfection at 2.8 and 16.7 mM glucose in INS-1 832/13 cells is shown in (A); insulin secretion at l and 20 mM glucose in EndoC-βH1 cells (B). Insulin content is shown in both cell types upon glucose stimulation with similar levels of knockdown (C and D). Insulin secretion (at 2.8 and 16.7 mM glucose) and content in rat islets (E and F); total cellular protein was used for normalization both for insulin secretion and content. Data are expressed as mean ± SD (n = 3, INS-1 832/13, n = 3, EndoC-βH1, n = 4, rat islets) and were statistically compared with paired Student’s t test; ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. DIMT1, dimethyladenosine transferase 1.