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

To evaluate the potential use as a therapeutic agent for osteoporotic fractures, we examined the effects of intermittent administration of parathyroid hormone on fracture healing in ovariectomized rats. At three months post-ovariectomy, bilateral tibial shaft fractures were induced and stabilized by intramedullary nailing with Kirschnerwires. Saline, 17-estradiol, or recombinant human PTH(1-84) 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. 17-estradiol, a bone-resorption inhibiting agent, did not offer advantage in terms of fracture healing in ovariectomized rats. Our findings suggest that intermittent parathyroid hormone administration may benefit osteoporosis and fracture.