The Section on Developmental Gastroenterology and Nutrition was established to study (1) intestinal epithelial cell migration and differentiation and (2) the nutritional modifications of gene activity and expression in developing and adult mammals. With respect to epithelial cell migration, our efforts have been focused on the establishment of a primary cell culture system which will allow us to define those cell surface components which are responsible for cell attachment to the basement membrane. In addition, an intestinal organ culture system is being developed as an in vitro model of cellular locomotion along the crypt-villus axis, so that the roles of protein synthesis and hormonal influences on intestinal cell migration can be investigated. We are also continuing our research into the control of sucrase/isomaltase synthesis and the mode of incorporation of the complex into the intestinal brush-border membrane. Primary cultures of rat pancreatic exocrine cells are being established to elucidate the role of nutrition in the modulation of gene activity and expression. Initially, studies will focus in the modulation of gene adaptation of rat amylase in isolated cells and intact pancreas to carbohydrate in the media or the diet.