GPRC6A and parathyroid gland adenoma: The present study aims to investigate: 1) the effects of GlaOC and GluOC on the modulation of intracellular signaling pathways and of the parathyroid specific genes expression in human parathyroid tumor cells, 2) the expression of GPRC6A in parathyroid adenomas-derived cells, 3) the distinct effects of the stimulation with GlaOC or GluOC in HEK293A cells transfected with GPRC6A or CASR, and 4) the effects of GlaOC and GluOC on parathyroid cell apoptosis.