ROLE OF NA+/K+ PUMP IN PANCREATIC SECRETION

哺乳动物外分泌胰腺中的腺泡细胞和导管细胞均参与 关于胰液的信息。然而，人们对具体的情况知之甚少。 在这两种细胞中，液体和电解质分泌的机制， 或者这些机制是如何被激素和神经递质调节的 在刺激-反应耦合期间。最近的研究表明，积极的 Na+在腺泡和导管上皮细胞间的转运对 液体的产生和Na+的运输依赖于细胞的活性 质膜酶Na+，K+激活三磷酸腺苷酶(Na+/K+) 泵)。在拟议的研究中，Na+/K+泵在 将探索胰腺分泌。为了实现这一目标， 将从豚鼠身上制备分散的上皮细胞悬浮液 胰腺，经梯度离心法分离成富集群 在腺泡细胞或导管细胞中。每个细胞内Na+/K+泵的数量 类型和活性将通过哇巴因敏感性分析来确定 ~(86)Rb+摄取、哇巴因敏感氧耗和~3H-哇巴因结合 送到细胞里。前两种技术允许直接估计Na+/K+ 泵介导的转运活性及其与氧化的关系 细胞内的新陈代谢。最后一种技术不仅测量水泵 活性，也提供了一种手段，使Na+/K+泵的数量 每种细胞类型的细胞膜中的分子都可以确定。这个 胰腺促分泌物如缩胆囊素、血管活性肠肽、促胰液素、 和乙酰胆碱对Na+/K+泵活性的影响将被评估。进一步 将进行研究，以确定细胞内事件 偶联受体激活对离子转运活性的影响 酵素。这些将包括对离子依赖性的调查， 环核苷酸和钙离子等细胞内信使和代谢 能源需求。建议进行的研究将提供有关 激素和神经递质调节Na+/K+泵活性的途径 在胰腺外分泌腺泡上皮和导管上皮中。此信息 将被用来构建胰液的细胞模型 电解质分泌。这些数据也将奠定坚实的基础 为了进一步研究体液分泌功能障碍 某些胰腺疾病的特点，如胰腺炎和 囊性纤维化。

Both acinar and duct cells in the mammalian exocrine pancreas participate information of pancreatic juice. Little is known, however, of the specific mechanisms involved in fluid and electrolyte secretion in either cell type, or how these mechanisms are modulated by hormones and neurotransmitters during stimulus-response coupling. Recent studies suggest that active transport of Na+ across both acinar and duct epithelia is essential to fluid production and that Na+ transport is dependent on activity of the plasma membrane enzyme Na+, K+ activated adenosine triphosphatase (Na+/K+ pump). In the proposed research, the role of the Na+/K+ pump in pancreatinc secretion will be explored. To accomplish this goal, suspensions of dispersed epithelial cells will be prepared from guinea pig pancreas and separated by gradient centrifugation into populations enriched in either acinar or duct cells. The numbers of Na+/K+ pumps in each cell type and their activity will be determined by analysis of ouabain-sensitive 86Rb+ uptake, ouabain-sensitive oxygen consumption and 3H-ouabain binding to the cells. The former two techniques allow direct estimation of Na+/K+ pump-mediated transport activity and its relationship to oxidative metabolism in the cells. The last technique not only measures pump activity, but also provides a means by which the number of Na+/K+ pump molecules in the membranes of each cell type can be determined. The effects of pancreatic secretagogues such as cholecystokinin, VIP, secretin, and acetylcholine on Na+/K+ pump activity will be assessed. Further studies will be carried out to establish the intracellular events that couple receptor activation to alterations in activity of the ion transport enzyme. These will include investigation of ion dependencies, intracellular messengers such as cyclic nucleotides and Ca++, and metabolic energy requirements. The studies proposed will provide information on the ways in which hormones and neurotransmitters modulate Na+/K+ pump activity in acinar and duct epithelia of the exocrine pancreas. This information will be used to construct a cellular model of pancreatic fluid and electrolyte secretion. These data also will establish a strong foundation for further studies probing the dysfunctions in fluid secretion that are characteristic of certain diseases of the pancreas such as pancreatitis and cystic fibrosis.