ARNT and diabetes mellitus: ARNT also regulates glucose-stimulated insulin secretion in mouse β cells (Pillai et al., 2011) and is severely downregulated (by 98%) in the liver and pancreas of patients with diabetes (Gunton et al., 2005; Pillai et al., 2011), in addition the cardiac-specific loss of ARNT expression in mice leads to a phenotype that mimics diabetic cardiomyopathy (Wu et al., 2014).