Hair-cycle-dependent expression of parathyroid hormone-related protein and its type I receptor: evidence for regulation at the anagen to catagen transition.

The humoral hypercalcemia factor parathyroid hormone-related protein is a paracrine-signaling molecule that regulates the development of several organ systems, including the skin. In pathologic circumstances such as hypercalcemia and in development, parathyroid hormone-related protein signaling appears to be mediated by the type I parathyroid hormone/parathyroid hormone-related protein receptor. In order to clarify the role of the ligand and receptor pair in cutaneous biology, gene expression was monitored in a series of murine skin samples ranging from embryonic day 14 to 2 y with in situ hybridization and RNase protection.