Based on observations in isolated (ex vivo) islets, hypoglycemia has been postulated to stimulate glucagon secretion via intrinsic (Yu et al., 2019; Rorsman et al., 2014; Basco et al., 2018) and/or paracrine mechanisms (Briant et al., 2018b; Vergari et al., 2019). This evidence concerns the gene GCG and Hypoglycemia.