Expression of parathyroid hormone/parathyroid hormone-related protein receptor in vascular endothelial cells

The parathyroid hormone (PTH)/PTH-related protein (PTHrP) receptor has been reported to be expressed in many tissues, including vascular smooth-muscle cells (VSMCs), but it has not been identified in vascular endothelial cells. To determine whether vascular endothelial cells can express the PTH/PTHrP receptor, its gene expression was examined in simian virus 40-transformed rat lung vascular endothelial cells (TRLECs) by the reverse-transcription polymerase chain reaction (RT-PCR). Results in TRLEC, with rat VSMCs and kidney as controls, showed identical 741-bp products. Furthermore, incubation with PTHrP[1-34] reduced the thrombin-stimulated endothelin-1 (ET-1) expression in TRLECs. Our results demonstrate that vascular endothelial cells can express the PTH/PTHrP receptor and therefore are also a target tissue for PTHrP.