['To study the potential role of the 78kDa glucose regulated protein (GRP78) in the pathogenesis of acute pancreatitis (AP) in vitro.', 'AR42J cells were stimulated by cerulein or cerulein plus lipoplysaccharide (LPS). The severity of pancreatic inflammation was evaluated by amylase, lipase, TNF-a, and IL-6. Apoptosis was determined by flow cytometry; the expressions of apoptotic genes, GRP78 and the downstream molecules were determined by real-time quantitative PCR and Western blot.', 'After cerulein stimulation, the levels of amylase, lipase, TNF-a and IL-6 were all increased, with a more pronounced increase after cerulein plus LPS stimulation. Apoptosis was different in two cell models, high apoptosis in cerulein group; whereas cerulein plus LPS induced relatively less apoptosis. Apoptotic gene expressions revealed more pronounced increase in the cerulein group than those in cerulein plus LPS group. The expressions of GRP78 and downstream molecules were different in two cell models. GRP78 expression was down-regulated in cerulein group and upregulated in cerulein plus LPS group.'] Is the ER chaperone GRP78 associated with the severity of cerulein-induced pancreatic inflammation via regulating apoptosis of pancreatic acinar cells?