GCG and type 2 diabetes mellitus: Glucagon has indeed been postulated to play a key role in the development of type 2 diabetes (Unger & Cherrington 2012) and patients with T2DM are frequently reported to have postprandial hyperglucagonemia due to impaired glucose inhibition of glucagon secretion (Muller et al. 1970, Unger et al. 1970, Gerich et al. 1976, Felig et al. 1978, Butler & Rizza 1991, Kelley et al. 1994).