Vol 62, Supp. II (2011)
Review paper
Published online: 2011-09-21
Parathyroid hormone and its analogues — molecular mechanisms of action and efficacy of osteoporosis therapy
Abstract
Most medical agents currently applied in osteoporosis therapy act by inhibiting bone resorption and reducing bone remodelling, i.e. they
inhibit the process of bone mass loss by suppressing bone resorption processes. These drugs provide an ideal therapeutic option to prevent
osteoporosis progression. They however have a rather limited usefulness when the disease has already reached its advanced stages with distinctive
bone architecture lesions. The fracture risk reduction rate, achieved in the course of anti-resorptive therapy, is insufficient for patients
with severe osteoporosis to stop the downward spiral of their quality of life (QoL) with a simultaneously increasing threat of premature death.
The activity of the N-terminal fragment of 1–34 human parathormone (teriparatide — 1–34 rhPTH), a parathyroid hormone (PTH) analogue
obtained via genetic engineering , is expressed by increased bone metabolism, while promoting new bone tissue formation by stimulating
the activity of osteoblasts more than that of osteoclasts. The anabolic activity of PTH includes both its direct effect on the osteoblast cell
line, and its indirect actions exerted via its regulatory effects on selected growth factors, e.g. IGF-1 or sclerostin. However, the molecular
mechanisms responsible for the actual anabolic effects of PTH remain mostly still unclear.
Clinical studies have demonstrated that therapeutic protocols with the application of PTH analogues provide an effective protection against
all osteoporotic fracture types in post-menopausal women and in elderly men with advanced osteoporosis. Particular hopes are pinned
on the possibility of applying PTH in the therapy of post-steroid osteoporosis, mainly to suppress bone formation, the most important
pathological process in this regard.
The relatively short therapy period with a PTH analogue (24 months) should then be replaced and continued by anti-resorptive treatment.
(Pol J Endocrinol 2011; 62 (education supplement II): 32–36)
(Pol J Endocrinol 2011; 62 (education supplement II): 32–36)
Keywords: osteoporosistreatmentparathyroid hormoneteriparatide
![](https://journals.viamedica.pl/plugins/generic/popups/images/icons/close.png)