Gastrointestinal hormones in the regulation of gut function in health and disease

Gastrointestinal (GI) hormones play an essential role in the regulation of normal GI function. Gut hormones are short peptides that act as chemical messengers. These messengers allow gut cells to communicate with one another and with cells in other organs, notably the brain. A large number of gut peptides have been isolated in the laboratory. Structural similarity among hormones has led to their classification in families. Gut peptides are synthesized by specialized cells that are diffusely distributed throughout the GI tract. GI hormones activate a series of signal transduction pathways that result in specific biological responses by binding to cell-surface receptors, the majority of which are G-protein coupled. The action of gut peptides may occur through endocrine, paracrine (neurocrine), or autocrine pathways. Knowledge of gut-peptide biology has demonstrated the importance of these chemical mediators in the pathogenesis, diagnosis, and treatment of disease.