Microbiota play key roles in the intestinal immune and metabolic responses in these enteroendocrine cells via their fermentation product (short chain fatty acid), acetate.

[7] Hormones secreted include somatostatin, motilin, cholecystokinin, neurotensin, vasoactive intestinal peptide, and enteroglucagon.

[14] I cells secrete cholecystokinin (CCK), and have the highest mucosal density in the duodenum with a decreasing amount throughout the small intestine.

Located in a increasing manner throughout the small intestine, with the highest levels found in the in ileum,[19] N cells release neurotensin, and control smooth muscle contraction.

Other hormones produced include cholecystokinin, somatostatin, vasoactive intestinal peptide, substance P, alpha and gamma-endorphin.

[10][24] Pancreatic enteroendocrine cells are located in the islets of Langerhans and produce most importantly the hormones insulin and glucagon.