Neurohumoral control of the exocrine pancreas

Recent advances in the study of pancreatic exocrine secretion are reviewed, with an emphasis on neurohumoral mechanisms. In the past year, cDNA for th e human pancreatic sodium-bicarbonate cotransporter was cloned, and the exp ressed protein was localized to pancreatic acini and ductal cells. Recent i nformation suggests that the cholecystokinin B receptor has a role in pancr eatic amylase release. Further evidence supports the concept of a protease- sensitive negative feedback mechanism regulating pancreatic exocrine secret ion. Study of the expression of the receptors responsible for the regulatio n of pancreatic function has proven fruitful in the determination of the mo lecular mechanisms of hormone signal transduction and desensitization. Stud ies of peptide 1, pituitary adenylate cyclase-activating peptide, and gastr in-releasing peptide have shown how these peptides participate in the regul ation of pancreatic secretion and have provided information on intracellula r signaling pathways obtained using rat pancreatic tumor cells, Neural regu lation via cholinergic receptors in isolated pancreatic acini and the mecha nisms responsible for other neurotransmitters, such as calcitonin gene-rela ted peptide, histamine, and dopamine, are reviewed. This review highlights recent discoveries in the neurohumoral regulation of pancreatic exocrine se cretion. (C) 1999 Lippincott Williams & Wilkins, Inc.