NONRUMINANT NUTRITION SYMPOSIUM: The role of glucagon-like peptide-2 in controlling intestinal function in human infants: Regulator or bystander?

The regulation of nutrient absorptive capacity is a critical factor in the normal growth and development of infants of all species. In human infants this is a common problem after surgical resection; the process of adaptation or upregulation of nutrient transport capacity is the physiologic process, which allows patients to transition to enteral feeding. The specific mechanisms that control this are still relatively poorly understood but are likely relevant for most mammals with an ontogeny of intestinal function related to the weaning process. Many actions of the entero-endocrine hormone glucagon-like peptide (GLP)-2 indicate that it may be a key factor in regulating physiologic intestinal development, nutrient absorptive capacity, and the process of adaptative upregulation of nutrient absorption after resection. This article will review the biology of GLP-2, which is preserved across a broad range of species. This will include the production of GLP-2 in the L cell, the regulation of GLP-2 release, and the mechanism of action. The GLP-2 receptor is specifically located on enteric neurons and pericryptal myofibroblast; thus, effects on the intestinal mucosa involve a second messenger. We will review the functioning of this system in the developing human infant and the role of GLP-2 in the regulation of adaptation, with the general implications for nutrient absorption in animals and humans.