PTHrP(1–36) as a skeletal anabolic agent for the treatment of osteoporosis

Parathyroid hormone-related protein (1–36) [(PTHrP(1–36)] has been shown to be one of the authentic secretory forms of PTHrP. Human studies employing this peptide have demonstrated that it is equipotent to parathyroid hormone (1–34). This observation, together with the observations that: (1) both peptides employ the same receptors; (2) both bind to this PTH/PTHrP receptor with equal affinity and activate the PTH/PTHrP receptor intracellular signaling pathways with the same efficacy; (3) both peptides are effective anabolic skeletal agents in laboratory animals; and (4) PTHrP is likely to be the endogenous skeletal ligand for the PTH/PTHrP receptor, collectively suggest that PTHrP (1–36) should be as equally effective as PTH(1–34) as an anabolic skeletal agent. In this mini-review, the theoretical basis for the exploration and development of PTHrP(1–36) as a potential therapeutic agent for osteoporosis is considered.