The research prjects outlined in this application are designed to evaluate the relationship between the synthesis of macromolecules in the exocrine glands and intestine and their intracellular processing and/or secretion and release. Since patterns of macromolecular synthesis are direct expressions of gene action, the role of development in the specialization of these functions will also be examined. Emphasis will be placed on the mechanisms by which hormones and other mediators control gene expression. Parotid and submaxillary glands will be studied in vivo and in vitro to relate secretory and synthetic events and immature animals will be studied in order to define the developmental timing of the ability of exocrine glands to respond to stimuli known to effect mature tissues. In the intestine RNA and protein synthesis will be studied during development in relation to cell migration and maturation of digestive enzymes. Other experiments will concentrate on the biochemical potential of the crypt cell and its control during development.