Reconstructing the skeleton with intermittent parathyroid hormone.

Abstract

The aim of treating osteoporosis is to restore bone strength by increasing its mass and reconstructing its architecture. Antiresorptive drugs reduce bone remodeling, allowing more complete secondary mineralization of the existing bone; the mass, macro- and microarchitecture of the bone remains unchanged. Anabolic agents have the potential to achieve this goal. Parathyroid hormone (PTH) is famous for its catabolic actions. Its anabolic effects, known by a select few over 70 years ago, are finally being appreciated. There is widely reproduced and compelling evidence in a range of species made osteoporotic by gonadectomy that intermittent PTH administration restores bone strength by stimulating new bone formation on the periosteal (outer) and endosteal (inner) bone surfaces, enlarging bone diameter, thickening the cortices and existing trabeculae, and perhaps increasing trabecular numbers and their connectivity.