RENAL INTERCALATED CELL REGULATION AND DIFFERENTIATION

这项研究项目的主要目标是调查 肾功能调节的细胞和亚细胞机制 通过集合管的酸碱运输和追踪成熟度 这种转运过程可以追溯到围产期。建议数 研究将集中在两种类型的酸碱转运细胞上 在集合管中鉴定了H+和HCO3离子的分泌 嵌(富含线粒体的)细胞。识别性和功能性 兔离体集合管中单个细胞的测定 将用最近开发的荧光染色技术进行， 包括那些探测线粒体、碳水化合物存在的 凝集素的脱水酶活性、胞吞/胞吐和表面结合 并允许测量细胞的pH值。将测量净HCO3离子传输 用微量热法测定。为了确定分子的功能极性， H+-ATPase定位的两种嵌合细胞 和氯-HCO3离子交换剂，鲁米诺阴离子取代氯离子的效果 对HCO3离子转运和胞内pH的影响将进行研究。因为 髓集合管高H+分泌率的特点 (MCT)可能是由于相对酸性的髓质造成的条件反射 环境，调节HCO3离子在这一节段的运输 将对慢性全身性碱中毒进行检查，并将结果与 存在大量分泌H+和HCO3离子的嵌合细胞。 大脑皮质收集中H+和HCO3离子分泌细胞的频率 慢性精神障碍动物的肾小管(CCT) 代谢和呼吸性酸碱状况与循环 矿物皮质激素水平将与HCO3离子的测量结果进行比较 运输以证实嵌入细胞可以被诱导的假说 来反转它们的功能极性。函数式的发展 分化的间质细胞(碳细胞)的特性 脱水酶、细胞pH、内吞/胞吐、表面糖蛋白)将 追溯到围产期和胚胎期，以便建立 嵌套细胞的命运图。作为调查的一部分， 确定细胞何时以及如何致力于分泌酸或 碱基，插层和中间层之间是否有通信 在未成熟的CCT中将建立主细胞。这些研究 这个应用程序中描述的内容应该让我们更好地理解 代谢和呼吸性酸碱紊乱，盐皮质激素 过量，遗传因素影响调节和发展 嵌插细胞。

The major objectives of this research project are to investigate the cellular and subcellular mechanisms responsible for the renal regulation of acid-base transport by the collecting duct and to trace the maturation of such transport processes back to the perinatal period. The proposed studies will focus on the two types of acid-base transporting cells identified in the collecting duct, the H+- and HCO3 ion-secreting intercalated (mitochondria-rich) cells. Identification and functional assay of individual cells in the isolated perfused rabbit collecting duct will be performed with recently developed fluorescence staining techniques, including those which probe for the presence of mitochondria, carbonic anhydrase activity, endocytosis/exocytosis and surface binding of lectins and permit measurement of cell pH. Net HCO3 ion transport will be measured by microcalorimetry. In order to identify the functional polarity of the two types of intercalated cells with respect to location of the H+-ATPase and Cl-HCO3 ion exchanger, the effect of luminal anion substitution for Cl- on HCO3 ion transport and intracellular pH will be studied. Because the high rate of H+ secretion characteristic of the medullary collecting tubule (MCT) may be due to conditioning by a relatively acidic medullary environment, regulation of HCO3 ion transport in this segment in response to chronic systemic alkalosis will be examined and the findings correlated with the numbers of H+- and HCO3 ion secreting intercalated cells present. The frequencies of H+- and HCO3 ion-secreting cells in cortical collecting tubules (CCT) obtained from animals subjected to chronic disturbances in metabolic and respiratory acid-base status and circulating mineralocorticoid levels will be compared with measurements of HCO3 ion transport to confirm the hypothesis that intercalated cells can be induced to reverse their functional polarity. The development of functional characteristics of the differentiated intercalated cell (carbonic anhydrase, cell pH, endocytosis/exocytosis, surface glycoproteins) will be traced back to the perinatal and embryonic periods in order to establish a fate map for the intercalated cell. As part of the investigation to determine when and how the cell becomes committed to secreting acid or base, the presence or absence of communication between intercalated and principal cells will be established in the immature CCT. The studies described in this application should allow us to better understand how metabolic and respiratory acid-base perturbations, mineralocorticoid excess, and genetic factors influence regulation and development of the intercalated cell.