CASR and tumor of parathyroid gland: In order to rule out non-specific influx as a potential confounding factor for our calcium sensing assay, we compared the flux responses of parathyroid tumor sections to extracellular calcium challenge in the presence or absence of the CASR-specific pharmacological compounds cinacalcet, a calcimimetic agent, or NPS-2143, a calcilytic agent [22, 23].