2023 Volume 76 Issue 3 Pages 149-157
The gastrointestinal tract acts as an interface between the external and internal milieux of the body. Among a variety of cells in the gastrointestinal tract, enteroendocrine cells are known to receive molecular information from the lumen, also from outside the body, secrete gastrointestinal hormones to the inside of the body, and transmit food information to the body. For example, proteins are fragmented by gastrointestinal enzymes with different substrate specificities, generating a vast number of molecular species. Enzymatic digests, which were previously made up of unidentified molecules, can now be detected and annotated comprehensively. Furthermore, many bioactive molecules produced by enzymatic digestion have been discovered, and the structural rules necessary for their bioactivity have been clarified. This has led to the identification of exogenous signals derived from food at the molecular level and a marked increase in the resolution of interactions with the gastrointestinal tract. In this review, we focus on exogenous peptides, including food-derived peptides, and provide an overview of their regulation of gastrointestinal hormone signaling. In addition, we present examples of peptides with diverse molecular structures and bioactivities that have become excellent probes for revealing new food signaling pathways and age-related alterations.
