ABSTRACT
To evaluate the anabolic effects of human recombinant parathyroid hormone [hrPTH(1-84)], we examined effect of low-dose and high-dose of [hrPTH(1-84)] and estradiol on bone histomorphometry in ovariectomized rats. Sixty Sprague-Dawley female rats aged 8~10 weeks were used. Eight weeks after ovariectomy, or sham operation, rats were given daily sc injection of hrPTH (1-84), 30 pg/kg (OVX+L group), 150 pg/kg (OVX+H group), 17-estradiol (30 pg/kg, OVX+E group) or vehicle (OVX+V group) for 4 weeks. After double tetracycline labeling, all rats were killed at day 84. We completed the histomorphometric analysis of distal femoral metaphyseal cancellous bone for trabecular bone volume (TBV), mean trabecular plate thickness (MTPT), mean trabecular plate density (MTPD), mean trabecular plate separation (MTPS), mean osteoid seam width (OSW) and appositional rate (AR). The histomorphometric parameters (TBV, MTPT, OSW and AR) of trabecular bone mass in (OVX+E) group were higher than those in (OVX+V) group. The TBV of trabecular bone in PTH treated groups were higher than that in sham operated, (OVX+V) and (OVX+E) group. The histomorphometric parameters (TBV, MTPD, OSW and AR) of trabecular bone mass in (OVX+H) group showed a tendency to be higher than those in (OVX+L) group, but statistically not significant. In conclusion, Low dose (30 mg/kg) hrPTH (1-84) also shows a sufficient anabolic effect on trabecular bone.