[2] The sphincter regulates the secretion of pancreatic juice and bile into the duodenum.

[5] The sphincter of Oddi is relaxed by the hormone cholecystokinin[6][7] via vasoactive intestinal peptide.

[citation needed] Opiates may cause spasms of the sphincter of Oddi, leading to increased serum amylase levels.

[10] This description followed extensive research into the physiology of dogs and detailed histological examinations of humans and many other species.

[1] In many mammals (including mice, guinea pigs, dogs, and opossums), the smooth muscle around the ampulla of Vater does not form a sphincter.