The calcium-sensing receptor (CaSR), a receptor which senses extracellular levels of calcium ion, is also classified as a member of the family of class C GPCRs. The release of parathyroid hormone (PTH) is inhibited in response to elevations in plasma calcium concentrations and activation of the calcium receptor by activating the phospholipase C (PLC) pathway, presumably through a Gqα type of G protein.
 Calcium-sensing receptor and calcimimetic agents. J.W. Coburn, L. Elangovan, W.G. Goodman, J.M. Frazaõ. Kidney Int. Suppl. 1999, 73, S52-58.