Enteroglucagon is a peptide hormone derived from preproglucagon. It is a gastrointestinal hormone, secreted from mucosal cells primarily of the colon and terminal ileum.^[1] It consists of 37 amino acids. Enteroglucagon is released when fats and glucose are present in the small intestine; which decrease the motility to allow sufficient time for these nutrients to be absorbed.

Discovery

In 1948, Sutherland and De Duve identified a gastrointestinal glucagon-like material in gastric mucosa,^[2] the term "enteroglucagon" was used to describe this material that shared a similar immunoreactivity with glucagon.^[3] A half-century later, Brubaker and Drucker^[4] studied proglucagon gene expression, they discovered the function of enteroglucagon is related to the growth of intestinal epithelium.^[5]

Function

Enteroglucagon is a proglucagon-derived peptide or enteroendocrine cells derived peptide in the small intestine. Preproglucagon undergoes post translational modification to release glucagon-like peptides (GLP-1 and GLP-2) and other molecules derived from L-cells of intestine. GLP-1 is derived from a class of intestinal hormones called incretin and the molecule exists in two forms GLP-1(7-37) and GLP-1(7-36) amide.^[6] GLP-1 form of incretin starts circulating in response to a high blood glucose level. Incretin effect is a negative feedback loop between glucose and insulin level, it promotes insulin release from beta cells of pancreas islet and suppresses glucagon when the glucose level is high.^[7] In vertebrate mammals, GLP-2 sequences are highly conversed in the intestine.^[2] The molecule functions as a part of adaptive response, such that contributes intestinal growth, proliferation effect, intestinal dilation (increases the mucosal blood flow) and reduces the chance of apoptosis.^[2]

Clinical significance

GLP-1 is effective at reducing blood glucose levels. GLP-1 analogs have a significant therapeutic effect and high efficacy on diabetes treatments and hypoglycemia prevention.^[8] Proliferation effect and trophic effect on the small intestine, GLP-2 is used as a therapy to support patients with short-bowel syndrome and other underlying intestinal conditions.^[9]