Estrogen and bone. Marshall R. Urist's contributions.

Estrogens have profound effects on the maintenance of bone mass. Urist's early studies showed species differences in reactions of bone to estrogens and in their ability to inhibit endosteal resorption and to reduce the number of osteoclasts. It is now clear that estrogens are anticatabolic as quantified by kinetic and radiographic studies. The clinical use of this important action of estrogens for the prevention and treatment of osteoporosis has recently been accepted by the NIH Consensus on Treatment of Osteoporosis and by the Food and Drug Administration. The relation of hip fractures to osteoporosis and vertebral compressions, shown by Urist et al. in 1959, is now clarified by direct noninvasive measurement of vertebral spongiosa, which is preferentially involved. Prevention of bone loss and fractures by estrogen has now been established morphometrically and epidemiologically; dose-response curves are available for four preparations. Urist showed in 1948 that estrogens are ineffective in vitro; it is now known that bone lacks estrogen receptors. Their antiosteolytic action appears to be mediated by calcitonin. As a consequence of all these studies, the serious human and public health problem of postmenopausal osteoporosis, with fractures of the vertebrae, wrists, and hips, deformity, and death, is one of the few geriatric disorders for which effective and safe prophylaxis is now practical.