Kallikrein in rat pancreatic tissue after beta cell destruction or acinar cell atrophy

The purpose of this study was to determine whether glandular kallikrein in rat pancreas is located in the beta cells of the endocrine pancreas or in the acinar cells of the exocrine pancreas. Kallikrein was measured by radial immunodiffusion and a direct radioimmunoassay in homogenates of pancreas obtained from 1) control rats, 2) rats with pancreatic beta cells selectively destroyed by streptozotocin, and 3) rats with acinar cell atrophy induced by pancreatic duct occlusion. Beta cell destruction was confirmed by the presence of hyperglycemia and by an almost total depletion of insulin-producing cells as demonstrated immunohistochemically. Acinar cell atrophy was confirmed histologically and by an almost total depletion of trypsin-like enzymes in pancreatic homogenates. The concentration of kallikrein in pancreatic homogenates was unchanged after beta cell destruction, whereas it was greatly decreased following acinar cell atrophy. Kallikrein was, by immunohistochemistry, demonstrated in the acinar cell only. The immunohistochemical localization of kallikrein agrees with the above results. These studies strongly indicate that kallikrein is predominantly located in the acinar cells of the exocrine pancreas.