Study Describes Action of Estrogen in Protecting Bone

Researchers at the University at Buffalo have described a novel pathway by which estradiol, the primary estrogen in humans, aids in maintaining bone density, a function critical to avoiding osteoporosis. It is well known that estrogen is essential for healthy bone, and that when the production of estrogen is reduced, as occurs normally in postmenopausal women and pathogenically after exposure to radiation or chemotherapeutic drugs, bones become brittle and break easily. However, the mechanisms involved aren't clearly understood. The new study found that one way estradiol helps to maintain bone density is by stopping the activation of an enzyme known as caspase-3. Also called the executioner caspase, caspase-3 is the central player in initiating the process of apoptosis, or programmed cell death of osteoblasts, the bone cells that aid in the growth and development of new bone and teeth. Results of the study will be presented Friday, March 23, at the International Association of Dental Research meeting in New Orleans. Peter G. Bradford, Ph.D., senior author on the study said of the results: "Basic and clinical studies have shown that estrogens can prevent both bone loss and reduce the incidence of bone fractures. Our research at the molecular and cellular level suggests that the underlying basis of this protective effect of estrogens involves the prevention of apoptosis in osteoblasts and that the key event in this prevention is the inhibition of caspase-3 activity."... Whole article: "www.buffalo.edu":[ http://www.buffalo.edu/news/fast-execute.cgi/article-page.html?article=85070009]

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