The diversity of pancreatic islet cells was first described in 1907 by Lane, who categorized them into A cells (α cells) and B cells (β cells).8 In 1923, Kim and Murlin discovered glucagon, a substance that induces hyperglycemia.9 The source of glucagon remained unknown until 1962 when α cells were identified as its origin. This evidence concerns the gene GCG and Hyperglycemia.