Intercalated cells (ICs) are found in the connecting tubule and the collecting duct. Of the three IC subtypes identified, type B intercalated cells are one of the best characterized and known to mediate Cl- absorption and HCO3- secretion, largely through the anion exchanger pendrin. This exchanger is thought to act in tandem with the Na+-dependent Cl-/HCO3- exchanger, NDCBE, to mediate net NaCl absorption. Pendrin is stimulated by angiotensin II and aldosterone administration via the angiotensin type 1a and the mineralocorticoid receptors, respectively. It is also stimulated in models of metabolic alkalosis, such as with NaHCO3 administration. In some rodent models, pendrin-mediated HCO3- secretion modulates acid-base balance. However, of probably more physiological or clinical significance is the role of these pendrin-positive ICs in blood pressure regulation, which occurs, at least in part, through pendrin-mediated renal Cl- absorption, as well as their effect on the epithelial Na+ channel, ENaC. Aldosterone stimulates ENaC directly through principal cell mineralocorticoid hormone receptor (ligand) binding and also indirectly through its effect on pendrin expression and function. In so doing, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. In addition to its role in Na+ and Cl- balance, pendrin affects the balance of other ions, such as K+ and I-. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contribution of pendrin-positive ICs in the kidney to distal nephron function and blood pressure.

中文翻译：

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Pendrin 阳性闰细胞的肾脏生理学。

闰细胞 (IC) 存在于连接小管和集合管中。在已确定的三种 IC 亚型中，B 型嵌入细胞是特征最明确且已知介导 Cl- 吸收和 HCO3- 分泌（主要通过阴离子交换剂 pendrin）的细胞之一。该交换器被认为与 Na+ 依赖性 Cl-/HCO3- 交换器 NDCBE 协同作用，以介导净 NaCl 吸收。Pendrin 分别通过 1a 型血管紧张素和盐皮质激素受体受到血管紧张素 II 和醛固酮的刺激。它在代谢性碱中毒模型中也会受到刺激，例如使用 NaHCO3 给药。在一些啮齿动物模型中，pendrin 介导的 HCO3 分泌调节酸碱平衡。然而，更具有生理或临床意义的可能是这些 pendrin 阳性 IC 在血压调节中的作用，这种作用至少部分是通过 pendrin 介导的肾 Cl- 吸收而发生的，以及它们对上皮 Na+ 通道的影响，ENaC。醛固酮通过主细胞盐皮质激素受体（配体）结合直接刺激 ENaC，也通过其对 pendrin 表达和功能的影响间接刺激 ENaC。在此过程中，pendrin 有助于醛固酮升压反应。Pendrin 还可以部分通过其在肾上腺髓质中的作用（调节儿茶酚胺的释放）或通过对血管收缩力的间接影响来调节血压。除了在 Na+ 和 Cl- 平衡中发挥作用外，pendrin 还影响其他离子的平衡，例如 K+ 和 I-。本综述描述了醛固酮和血管紧张素 II 诱导的信号传导如何调节 pendrin 以及肾脏中 pendrin 阳性 IC 对远端肾单位功能和血压的贡献。