The overall objective of this project is to investigate the control of cellular proliferation in the isoproterenol-stimulated salivary glands of mice. This is a model of stimulated DNA synthesis in which a single intraperitoneal administration of purified chemical compound, the synthetic catacholamine - isoproterenol, causes a marked stimulation of DNA synthesis and cell division in the acinar cells of the parotid and of the submandibular glands. In the past years we have established several parameters of this model and have described in detail the sequence of biochemical events that occur between the application of the stimulus, that is, the administration of isoproterenol, and the onset of DNA synthesis 20 hrs. later. We now intend to continue these studies and to try to determine which of the biochemical events thus far described are related to DNA synthesis and which are simply concomitant.