胰腺导管系统对内分泌的功能影响及其可能机制

Effects and possible mechanisms of pancreatic duct epithelial cells on insulin secretion of the islet β cells

胰腺的内、外分泌系统在形态学和功能上存在密切联系。胰腺导管腔内的成分可能作用于一些直接开口于管腔的内分泌细胞,并通过内分泌细胞之间的缝隙连接,最终对更大量的内分泌细胞产生特殊的刺激。胰腺导管上皮细胞主要分泌富含碳酸氢钠(NaHCO3)的胰液,故胰液中NaHCO3可能对内分泌胰岛产生功能影响。研究表明囊性纤维化跨膜转导因子(cystic fibrosis transmembrane conductance regulator,CFTR)在胰腺导管上皮细胞大量表达,对分泌碳酸氢根(HCO3-)至关重要;但CFTR是否在内分泌胰岛表达仍有争议,在内分泌胰岛的作用更是鲜有研究。深入研究胰腺导管系统对内分泌胰腺功能上的影响及其机制,对糖尿病的防治及新药的开发具有积极意义。

Whereas the endocrine and the exocrine pancreas have been generally regarded as independent entities in morphology and function, evidence for close interactions between the two glandular components has been obtained. A recent report has suggested that substance secreted into the pancreatic juice could exert an action on islet cells that directly face the duct lumina, and eventually bring a peculiar stimuli to a larger population of islet cells through gap junctions among them. Pancreatic duct epithelial cells secrete pancreatic juice rich in sodium bicarbonate which may have a functional effect on islet cells. It has long been recognized that cystic fibrosis transmembrane conductance regulator （CFTR） is abundant in small pancreatic duct epithelial cells and quite important for the secretion of bicarbonate. However, the expression of CFTR in pancreatic islet is not completely defined and few studies have reported about the role of CFTR expressed in islet ceils. Further study on the influence and mechanism of pancreatic duct epithelial cells to the islet is needed, and it may be meaningful for the prevention, therapy of and perhaps the new drug for diabetes mellitus.