Université Paris-Descartes, Sorbonne Paris-Cité, F-75006 Paris, France.
Curr Opin Nephrol Hypertens. 2013 Sep;22(5):566-71. doi: 10.1097/MNH.0b013e328363ff5f.
Changes in extracellular calcium concentration affect several functions of the renal tubule. The calcium-sensing receptor (CaSR), initially identified in the parathyroid gland cells, is also expressed in the kidney and was assumed to mediate all effects of extracellular calcium on the renal tubule. The purpose of this review is to critically review the evidence supporting this assumption.
Recent results confirm that, in the kidney, the CaSR is mainly expressed in the thick ascending limb of the loop of Henle. There, it is involved in the control of calcium reabsorption, independently of its action on parathyroid hormone secretion, through an effect on the paracellular pathway permeability. Although extracellular calcium affects transports other than that of calcium, the direct evidence that CaSR is involved in these effects is still lacking in many instances.
As the CaSR in the kidney controls calcium reabsorption and excretion and subsequently affects blood calcium concentration, agonists and antagonists of the CaSR could be used to control blood calcium concentration in patients who have lost their ability to regulate parathyroid hormone secretion. In addition, more work is needed to further decipher the molecular mechanisms through which CaSR determines calcium transport in the loop of Henle.
细胞外钙离子浓度的变化会影响肾小管的多种功能。钙敏感受体（CaSR）最初在甲状旁腺细胞中被发现，也在肾脏中表达，被认为介导细胞外钙离子对肾小管的所有作用。本综述的目的是批判性地回顾支持这一假设的证据。
最近的结果证实，在肾脏中，CaSR 主要在 Henle 袢的升支粗段表达。在那里，它通过对细胞旁途径通透性的影响，独立于其对甲状旁腺激素分泌的作用，参与钙重吸收的控制。尽管细胞外钙离子会影响除钙以外的转运，但在许多情况下，CaSR 参与这些作用的直接证据仍然缺乏。
由于肾脏中的 CaSR 控制钙的重吸收和排泄，从而影响血液钙浓度，CaSR 的激动剂和拮抗剂可用于控制甲状旁腺激素分泌能力丧失的患者的血钙浓度。此外，还需要进一步的研究来进一步阐明 CaSR 通过何种分子机制来确定 Henle 袢中的钙转运。
