[Piperazinyl estrone, a new estrogen derivant, prevents bone loss in aged rats].

The purpose of this study was to determine the effects of piperazinyl estrone, a new estrogen derivative, on bone turnover, bone mass and uterine weight in female aged rats. Thirty-two Sprague-Dawley female rats at the age of 22 months were treated with vehicle or with piperazinyl estrone (P-E) at 0.5, 1 and 2 mg/kg/day, subcutaneous injection for 1 month. At the time of death, the uterine weight was measured and bone histomorphometric analysis of proximal tibial metaphyses (PTM) was performed in undecalcified sections. Compared with control, bone mass was increased in P-E groups. Dynamic data showed that bone resorption were decreased, but bone formation was not declined and bone mass was increased significantly in P-E (1 mg/kg day) group. There was no significant change in uterine weight. The findings of this study show that piperazinyl estrone at dosage of 1 mg/kg/d is most efficacious in preventing the bone losses in aged rats and has no side effect on uterus.