[The calcium receptor and magnesium metabolism].

The calcium receptor (CaR), which regulates Ca(2+) homeostasis, senses Mg(2+) and participates in Mg(2+) metabolism mainly at the parathyroid gland and kidney as well as Ca(2+) metabolism. In the parathyroid gland, Mg(2+) suppresses parathyroid hormone (PTH) secretion by the activation of CaR, and regulates the sensitivity of CaR by its unique effect. In the kidney, the activation of CaR inhibits Mg(2+) reabsorption directly or indirectly, mainly at the downstream of loop of Henle.