Gastrointestinal hormones.

Much has been learned about the nature, localization, and biological actions of a wide assortment of peptides present in the gastrointestinal tract. Measurement of some of these peptides has been made possible by development of immunoassay techniques. In some instances, ample information has been gained about the roles of these gastrointestinal peptides in physiological events and in pathophysiological states. It is evident, however, that our knowledge of the true regulatory roles of these peptides and their participation and significance is in its earliest stages of development.