Gastrointestinal Peptides	

In contrast to most endocrine tissues in which hormone-producing cells are grouped together into anatomically distinct glands, the endocrine cells of the gastrointestinal tract are scattered throughout its length, and hence peptide concentrations in any one area are very low – around 10pmol/l. The majority of the peptides that are isolated are found in one region of the gut (Fig. 19.1). 

See later:
• Gut Neuropeptides
• Gastrin–Cholecystokinin Family
• Secretin Family
• GHRH in Gastrointestinal Endocrinology