ISOLATED COLLECTING TUBULE CELLS--ION TRANSPORT

隔离收集管细胞--离子传输

• 批准号: 3239278
• 负责人: GEZA FEJES-TOTH
• 金额: $ 11.33万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1994-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3239278
• 关键词: acid base balance; adenosinetriphosphatase; aldosterone; alkalosis; apical membrane; basolateral membrane; body water; calcium channel; cell sorting; cell type; cyclic AMP; electrolytes; homeostasis; ion transport; isolation perfusion; laboratory rabbit; membrane permeability; monoclonal antibody; nonelectrolyte transport; phosphates; potassium channel; renal tubular transport; respiratory acidosis; secretion; sodium channel

The collecting duct system of the mammalian nephron plays a critical role in regulating water and electrolyte balance. Its cellular heterogeneity, however, has greatly hampered attempts to characterize transport processes and their regulation at the cellular level. Cell specific monoclonal antibodies recently developed by the P.I. have now made it possible to isolate and cluture individual cell types of the collecting duct by immunoadsorption and fluorescence-activated cell sorting and study transport properties of these cells. Primary cultures of intercalated cells (ICC) and principal cells (PC), displaying differentiated functions, such as secretion of H+ and K+ and reabsorption of Na+, PO4, and Ca2+, can be maintained on permeable supports. Such cultures also retain their original hormonal responsiveness and express many of the antigens they posses in situ. Preliminary results obtained by these techniques provide the basis for the long-term objectives of this project, which are to elucidate (1) the mechanism of K+ secretion by PC; and (2) the role of ICC in acid-base homeostasis, Aim (1) proposes a detailed analysis of the cellular mechanism of the action of AVP on K+ secretion in PC monolayers. These studies will address the possibility that AVP exerts a dual action on PC, through the cAMP and intracellular Ca2+-messengers systems and will examine the contribution of alterations in K+ permeability and changes in driving forces for K+ in the mechanism of action of AVP. Aim (2) will also test for the possibility that K+ itself can modulate K+ secretion by causing adaptive changes, and that aldosterone modulates this response. Aim (2) involves a study of the mechanism of H+ secretion by cultured ICC. Specifically, we will examine the contribution of an apical H+-ATP-ase to acid secretion and will determine the mechanisms involved in base-disposal through the basolateral membrane. Finally, we will test the effect of aldosterone and changes in ion composition resembling those seen during metabolic/respiratory alkalosis and acidosis. The new information acquired by these studies should help to clarify the mechanisms controlling renal K+ secretion and acidification by the distal nephron, and consequently, lead to a better understanding of the etiology of the disturbances of acid-base and potassium homeostasis.

哺乳动物肾单位的集合管系统起着至关重要的作用 具有调节水、电解质平衡的作用。 它的蜂窝 然而，异质性极大地阻碍了表征的尝试 运输过程及其在细胞水平上的调节。 细胞 P.I. 最近开发的特异性单克隆抗体现在有 使得分离和培养单个细胞类型成为可能 通过免疫吸附和荧光激活细胞收集管 分类并研究这些细胞的运输特性。 原代培养物 闰细胞 (ICC) 和主细胞 (PC)，显示 分化的功能，例如 H+ 和 K+ 的分泌以及 Na+、PO4 和 Ca2+ 的重吸收，可在渗透性上维持 支持。 这些文化还保留了其原始的荷尔蒙 反应性并在原位表达它们拥有的许多抗原。 通过这些技术获得的初步结果为 该项目的长期目标是阐明 (1) PC分泌K+的机制； (2) ICC在酸碱平衡中的作用 稳态，目标（1）提出了对细胞的详细分析 AVP 对 PC 单层 K+ 分泌的作用机制。 这些 研究将解决 AVP 对以下疾病发挥双重作用的可能性： PC，通过 cAMP 和细胞内 Ca2+-信使系统，并将 检查 K+ 渗透性变化和变化的贡献 AVP 作用机制中 K+ 的驱动力。 目标 (2) 还将测试K+本身可以调节K+的可能性 通过引起适应性变化而分泌，并且醛固酮调节 这个回应。 目标（2）涉及H+机制的研究 由培养的ICC分泌。 具体来说，我们将检查 顶端 H+-ATP-ase 对酸分泌的贡献 通过以下方式确定参与基地处置的机制 基底外侧膜。 最后我们来测试一下醛固酮的效果 和离子成分的变化类似于在 代谢/呼吸性碱中毒和酸中毒。 新信息 这些研究获得的成果应该有助于阐明机制 通过远端肾单位控制肾 K+ 分泌和酸化， 因此，有助于更好地了解该病的病因 酸碱和钾稳态紊乱。