The role of aquaporin water channels in fluid secretion by the exocrine pancreas

摘要: The mammalian exocrine pancreas secretes a near-isosmotic fluid over wide osmolarity range. role of aquaporin (AQP) water channels in this process is now becoming clearer. AQP8 channels, which were initially cloned from rat pancreas, are expressed at the apical membrane pancreatic acinar cells and contribute to their osmotic permeability. However, secrete relatively little there no obvious defect function knockout mice. Most secreted by generated ductal epithelial cells, comprise only small fraction gland mass. In human secretion occurs mainly intercalated ducts, where express abundant AQP1 AQP5 alone basolateral membrane. mouse, interlobular ducts again co-localized but appear be low levels. Nonetheless, transepithelial permeability sufficient support observed rates. Furthermore, apical, not basolateral, application Hg2+ significantly reduces permeability, suggesting that may secretion. apparently normal output mice reflect presence