This gene encodes a member of the glucagon family of peptides. The encoded preproprotein is secreted by endocrine S cells in the proximal small intestinal mucosa as a prohormone, then proteolytically processed to generate the mature peptide hormone. The release of this active peptide hormone is stimulated by either fatty acids or acidic pH in the duodenum. This hormone stimulates the secretion of bile and bicarbonate in the duodenum, pancreatic and biliary ducts. [provided by RefSeq, Feb 2016].