[Estrogens, progestins and the bone].

Estrogens are the most effective agents in the prevention of post-menopausal osteoporosis, as witnessed by numerous epidemiological and clinical studies. They inhibit bone resorption by complex mechanisms, modulating the action of calciotropic hormones and facilitating the production by bone cells of proteinic factors (cytokines, bone growth factor). Recent studies suggest that estrogens might also stimulate bone formation directly. Moreover, synthetic progestins are thought to have a trophic effect on bone tissue. The effectiveness and excellent metabolic tolerance of the available compounds should widen the indications of replacement therapy in postmenopause.