Because the glucagon-producing α-cells harbor the ncNOS enzyme [9], which apparently is an important regulator of glucagon release [1], [2], [3], [4], [6], [18], [19], [20], [21], and because raised plasma levels of glucagon is a common feature of and contribute to human type 2 diabetes [22] we also performed parallel studies on glucagon secretion. This evidence concerns the gene NOS1 and type 2 diabetes mellitus.