The study is designed to improve the basis for diagnosis of pancreatitis, delineate its pathophysiology, describe its natural history and improve its treatment. Radioimmunoassay of pancreatic enzymes, glucagon, gastrin, parathormone, thyrocalcitonin, and insulin will be utilized to study both acute and chronic pancreatitis. The role of calcium metabolism in pancreatic secretion and pancreatitis will be studied. Fluid shifts and changes in vascular permeability will be studied in acute pancreatitis.