In addition to glucagon, a novel proglucagon-derived peptide, proglucagon 1-61 (PG 1-61) comprised of GRPP and glucagon, was identified as a major molecular form of glucagon in plasma from human patients with hyperglucagonemia-associated conditions: Type 2 diabetes and renal dysfunction, morbid obesity or gastric bypass surgery, and only after oral ingestion of macronutrients (103). Here, GCG is linked to morbid obesity.