['Smad6 is implicated in the inhibition of bone morphogenetic protein signalling. However, the function of Smad6 in the pancreas remains obscure.', 'To elucidate the unknown function of Smad6, we developed transgenic mice selectively expressing Smad6 in pancreatic acinar cells using a plasmid construct coding rat elastase 1 enhancer/promoter.', 'Smad6 transgenic mice had no specific distinguishing phenotype such as body weight, pancreatic wet weight and concentrations of pancreatic protein. However, Smad6 transgenic mice reacted to hyperstimulation by caerulein injection or a diet containing 0.5% ethionine. Maximal amylase release stimulated by CCK-8 was significantly decreased in Smad6 transgenic mice acini, and trypsin activities in transgenic mice acini were significantly increased after stimulation of CCK-8. There was no difference in effect of CCK-8 stimulation on the subsequent increase in intracellular free Ca2+ concentration ([Ca2+](i)) between wild-type and transgenic mice acini. These findings suggest that reduced pancreatic enzyme secretion was caused by the disorder of its downstream signal transduction pathways in acinar cells. The amino acid sequence at the N-terminus of Smad6 was similar to that of synaptosome-associated protein (SNAP) 25 interacting protein, which plays an important role in regulating exocytosis of pancreatic enzymes in acinar cells. Pancreatic SNAP25 protein levels in transgenic mice were decreased after caerulein-induced pancreatitis.'] Does increased expression of Smad6 deteriorate murine acute experimental pancreatitis in two models?