Parathyroid cells express a cell surface receptor, coupled to the mobilization of intracellular
Ca 2+, that is activated by increases in the concentration of extracellular Ca 2+ and by a
variety of other cations. This" Ca 2+ receptor"(CaR) serves as the primary physiological
regulator of parathyroid hormone secretion. Alterations in the CaR have been proposed to
underlie the increases in Ca 2+ set-point seen in primary hyperparathyroidism due to
parathyroid adenoma. We have isolated human CaR cDNAs from an adenomatous …