Changes in the intercellular junction of rat exocrine pancreatic cells induced by long term ethanol ingestion.

The findings of electron microscopic observation of the intercellular junctions of pancreatic exocrine cells from male Wistar rats that had been given ethanol ad libitum in place of water are described. In control animals, numerous tight junctions having a distinct pentalamellar structure were observed in the well developed interdigitations of the baso-lateral domain of both the ductal and centroacinar cells. This type of junction differed structurally as well as topographically from the occluding junctions situated in the apical part of the lateral domain and exhibited a tri-lamellar rather than a penta-lamellar structure. Further, this type of junction was not observed in the interdigitations between the acinar and centroacinar cells or in those between acinar cells. These specialized membrane structures became hypertrophic after 1 and 2 months of ethanol ingestion. That is, the interdigitated cell processes became elongated but the distribution density of the tight junctions was similar to that in control animals, so that the total number of tight junctions increased. After 3 months of ethanol ingestion, the interdigitated cell processes atrophied, the intercellular spaces widened, and the number of tight junctions markedly decreased. Thereafter, these changes were observed continuously in ethanol-treated animals. However, the occluding and adhering junctions were not markedly affected by ethanol intake.