Reductions in cardiomyocyte K+ current density in models of T1DM also involve defective channel expression (potentially involving AMPK signaling) [459], and action potential prolongation in Otsuka-Long-Evans-Tokushima Fatty rats is linked to down-regulation of endocardial Kv4.2 (voltage-gated K+ channel subfamily D) and transmural KChIP2 (K+ channel interacting protein) expression [454]. This evidence concerns the gene KCNIP2 and type 1 diabetes mellitus.