PAP, A PANCREATIC SECRETORY PROTEIN-INDUCED DURING ACUTE-PANCREATITIS, IS EXPRESSED IN RAT INTESTINE

The pancreatitis-associated protein (PAP) is a lectin-related secretor y protein present in small amounts in the rat pancreas and rapidly ove rexpressed during the acute phase of pancreatitis. We demonstrate in t his report that PAP is also expressed in rat intestine. A cDNA library from rat jejunum was probed with pancreatic PAP cDNA. The inserts of the selected recombinant clones corresponded to a transcript whose nuc leotide sequence was identical to that of pancreatic PAP mRNA. The tra nscript was detected in duodenum, jejunum, ileum, and colon. A protein with same molecular mass (16 kDa) and pI (8.2) as pancreatic PAP was actually immunodetected in ileum homogenate after separation by two-di mensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. I ntestinal PAP was immunolocalized to the epithelial cells of the lower part of the villi. The protein accounted respectively for 0.02, 0.05, and 0.1% of soluble proteins in duodenum, jejunum, and ileum homogena tes, as measured by enzyme-linked immunosorbent assay, and could not b e detected in stomach and colon. Influence of fasting and feeding on P AP mRNA concentration was analyzed in ileum. Concentration decreased b y 81 and 94% after animals were fasted for 24 and 48 h, respectively. Feeding restored the initial content within 6 h. On the other hand, in testinal PAP mRNA concentration was not altered during acute pancreati tis.