The classification of the human gastroenteropancreatic endocrine cells.

A description of the gastroenteropancreatic cells as identified by immunocytochemical techniques is presented. A functional classification of these cells is proposed where function is defined as the production of a chemical messenger be it a polypeptide or a biogenic amine. The discovery of the polypeptide-containing neurons has created a new area for investigation. This will be outlined briefly although the majority of the peptidergic-type synaptic profiles have as yet to be linked with the production of a particular polypeptide.