PDGFA and Hypercalcemia: Coadministration of cPTH and the lysyl oxidase inhibitor BAPN or the PDGF-A signaling antagonist trapidil to rats blunted the mineralization defect and peritrabecular fibrosis, respectively.(23) Additionally, trapidil was shown to reduce osteoclast surface and hypercalcemia in rats treated with cPTH.(16) Thus there may be a mechanistic connection between peritrabecular fibrosis and focal bone resorption in patients with chronic HPT.