A) Basal (2 mM) and glucose (20 mM) induced insulin secretion of islets isolated from 2 or 5 months old mice fed a normal chow (NFD) or from 5 months old mice fed a high fat diet (HFD) for 12 weeks; n = 300 islets per genotype and condition. Data are mean values ± SEM, (* p<0.05, WT vs KO; NS = not significant, WT vs KO; # p<0.05, WT vs WT or KO vs KO. B) NHA2 mRNA expression in islets of 2, 3.5, 5 and 12 months old mice fed a normal chow (NFD) or from 5 months old mice fed a high fat diet (HFD) for 12 weeks; n = 300–500 islets of 3–5 mice/group. Data are mean values ± SEM, (* p<0.05, vs indicated condition; # p<0.05, vs all other conditions).