Mp. Akhter et al., Effect of parathyroid hormone (hPTH[1-84]) treatment on bone mass and strength in ovariectomized rats, J CLIN DENS, 4(1), 2001, pp. 13-23
Skeletal fragility in osteoporotic patients is a prominent underlying cause
of low-trauma fractures of most bone sites in humans. Clinical research is
now focused on developing treatment strategies, including anabolic agents
such as parathyroid hormone (PTH), to recover osteoporosis related bone los
s. Female Sprague-Dawley rats (4.5 mos old) were allowed to become osteopen
ic for 10 wk postovariectomy. Eight rats were killed at the time of ovariec
tomy (-10 wk) as a baseline control; sham and ovariectomized (OVX) groups w
ere killed at wk 0. Eight rats per group (sham, OVX + vehicle, OVX + hPTH [
5 d/wk], and OVX + hPTH [3 d/wk]) were killed after 4, 8, 14, and 20 wk of
treatment with 50 mug/kg of human parathyroid hormone (hPTH[1-84]). Bone mi
neral content and density were measured only in the vertebral body. Bone st
rength was evaluated in the vertebral body, femoral diaphysis, femoral neck
, and distal femur. Significant, lasting osteopenia developed in the verteb
ral body of OVX rats by 10 wk postovariectomy. Bone mineral density of the
vertebral body partially recovered by 8 wk and fully recovered to that seen
in sham animals only by 20 wk posttreatment with either a 5 or 3 d/wk dosi
ng schedule of PTH[1-84]. Therefore, hPTH[1-84] (50 mug/kg) given either 3
or 5 d/wk fully restores vertebral and femoral bone strength in osteopenic
OVX rats.