Parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor (PTHR1) is a G protein coupled receptor which mediates the actions of both amino-terminal PTH and PTHrP fragments. The most abundant expression of PTHR1 is found in renal tubular cells and in osteoblasts, where the PTH/PTHrP receptor mediates the endocrine actions of PTH, and in prehypertrophic chondrocytes of the metaphyseal growth plate, where it mediates the autocrine/paracrine actions of PTHrP. Intact PTH (PTH 1-84) is compounded by a peptide of 84 amino acids (AA), the amino-terminal sequence, constituted by the first 34 AA (N-terminal structure), is necessary for its action.