Effect of human parathyroid hormone (PTH(1-34)) on experimental osteopenia of rats induced by ovariectomy.

The effect of human PTH(1-34) on the development of osteopenia induced by ovariectomy was investigated in immature female Sprague-Dawley rats. After the surgery, human PTH(1-34) was injected subcutaneously three times a week for 25 weeks. A reduction of serum calcium level and a tendency to increased serum alkaline phosphatase activity were seen in ovariectomized rats. The ovariectomized rat bones were characterized by reduction of dry weight, ash weight, calcium content and phosphorus content, but there was no change in length, volume and ash content in these bones. Human PTH(1-34) prevented the reduction of dry weight, ash weight, calcium content and phosphorus content dose dependently (1.5-6.0 micrograms/kg) in ovariectomized rats. It was concluded that pulsatile administration of human PTH(1-34) prevented the development of osteopenia induced by ovariectomy.