X. Trefoil peptide and EGF receptor/ligand transgenic mice.

The use of genetically engineered mice with both gain-of-function and loss-of-function mutations has been particularly informative about the normal and pathophysiological actions of a number of regulatory peptides of the gastrointestinal tract. This review highlights some of the major findings pertinent to the epidermal growth factor (EGF) receptor and its ligands, particularly the major gut ligand transforming growth factor-alpha, as well as the trefoil peptides. Both of these peptide families have important local actions in maintaining tissue homeostasis and repair after injury, and when mechanisms governing their regulation are disrupted they may contribute to disease progression. Future applications of transgenic technology to these areas are likely to be productive in furthering our understanding of the biology of these peptides in health and disease.