The effect of carbachol and isoprenaline on cell division in the exocrine pancreas of the rat.

The effect of muscarinic cholinergic receptor stimulation on pancreatic acinar cell division has been investigated. Muscarinic receptor stimulation, in addition to causing a 50% depletion of amylase in the pancreas after 4 h, resulted in a 400% increase in the incorporation of [6(-3)H]thymidine 27 h after drug administration. This increase in incorporation was dose-dependent. Autoradiography showed this increase to be due to an increased acinar cell labelling. Isoprenaline also increased the incorporation of [6(-3)H]thymidine into the pancreas but did not reduce enzyme levels. However, with isoprenaline there was no increase in acinar cell labelling. The possibility of a relationship between secretion and hyperplasia of acinar cells in the rat pancreas is discussed.