Effect of intermittent administration of parathyroid hormone on fracture healing in ovariectomized rats

The effects of intermittent administration of parathyroid hormone on fracture healing in ovariectomized rats were examined to evaluate its potential use as a therapeutic agent for osteoporotic fractures. Three months postovariectomy, bilateral tibial shaft fractures were induced and stabilized by intramedullary nailing with Kirschner wires. Saline, 17beta-estradiol (Sigma Chemical Corp, St Louis, Mo), or recombinant human parathyroid hormone (1-84) (Korean Green-Cross Pharm Corp, Seoul, Korea) was given once a day for 30 consecutive days during fracture healing. Fracture healing was assessed by morphometric and mechanical analysis of fracture callus. Intermittent parathyroid hormone administration increased the morphometric and mechanical parameters in a dose-dependent manner. A bone-resorption inhibiting agent, 17beta-estradiol did not offer advantage in terms of fracture healing in ovariectomized rats. Findings suggest intermittent parathyroid hormone administration may benefit osteoporosis and fracture.