Serum from rats with acute pancreatitis induces expression of the PAP mRNA in the pancreatic acinar cell line AR-42J.

PAP is a pancreatic secretory protein expressed in the pancreas during the acute phase of pancreatitis. We have investigated the effect of the serum from rats with acute pancreatitis (SAP) on the expression of the PAP mRNA in AR-42J cells. PAP mRNA is strongly induced by SAP in a dose-dependent manner. This induction is abolished by preheating the SAP or diminished by treating the cells with cycloheximide. In addition, amylase but not actin mRNA expression was induced by a different SAP factor. We transfected the AR-42J cells with a chimeric gene containing 1.2 kbp 5'-flanking region of the PAP promoter linked to the CAT reporter gene. The CAT activity was significatively increased in the cells, on treating them with SAP. Our results show: first, SAP contains factors responsible for the PAP mRNA expression and secondly, the cis-acting elements are localized within the 1.2 kbp upstream region of the transcription initiation site.