CaSR
CaSR(The calcium-sensing receptor) is a Class C G-protein coupled receptor which senses extracellular levels of calcium ion. It is primarily expressed in the parathyroid gland and the renal tubules of the kidney. In the parathyroid gland, the calcium-sensing receptor controls calcium homeostasis by regulating the release of parathyroid hormone (PTH). In the kidney it has an inhibitory effect on the reabsorbtion of calcium, potassium, sodium, and water depending on which segment of the tubule is being activated.