Effects of human PTH(1-34) and bisphosphonate on the osteopenic rat model

It has been demonstrated that the intermittent administration of human parathyroid hormone (hPTH) is beneficial for restoration of bone mass in osteoporotic patients. The mechanisms of anabolic effects of hPTH have been determined by ovariectomized rat models and other larger remodeling animals. However, treatment with hPTH may increase the cancellous bone mass at the expense of cortical bone mass and cessation of the treatment results in rapid bone loss. Efforts have been made to maintain newly formed bone mass after withdrawal of the hPTH treatment. These issues are not well understood. In this article, the authors would like to represent previous studies of their own and others concerning these issues.