NOD mice were treated with MOTS-c daily (0.5 mg/kg/day; IP) for (A-C) 30 weeks (n=6) and (D-G) 18 weeks (n=10) of age. (A) Diabetes incidence was observed until 30 weeks of age. (B) Random blood glucose (RBG) level and (C) body weight were measured twice a week; two-way repeated measures ANOVA. A week before euthanasia, (D) IPGTT was performed by injecting ᴅ-glucose (2 g/kg; IP) in time-course and AUCs for blood glucose were calculated; two-tailed t-test (for AUC) and two-way (for time-dependent IPGTT) ANOVA. (E) Serum obtained before and after glucose injection in IPGTT were assessed for insulin concentration; two-tailed t-test. Paraffinized NOD pancreas were stained with (F) H&E for assessment of insulitis score and (G) IF staining of insulin. (F, G) Pancreatic sections were prepared as described and the representative data from ten pancreases with ten sections for each mouse (n=10); two-tailed t-test (for insulitis score), error bars are S.E.M. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001. Scale bars: 25 μm