Biosynthesis, segregation, and secretion of exportable proteins by the exocrine pancreas.

Recent findings that contribute to an understanding of the secretory process in the pancreatic exocrine cell are reviewed. These include 1) the separation, identification, and characterization of secreted proteins by two-dimensional gel electrophoresis, 2) the intracellular route and timetable of movement of secretory proteins from one intracellular compartment to another, 3) the evidence that suggests that all enzymes and zymogens secreted by the pancreas are segregated and transported within a single intracellular pathway, and 4) the mechanism by which presecretory proteins are thought to be transported across the lipid bilayer of the rough endoplasmic reticulum (the transport peptide hypothesis).