Concentration of cytosolic estrogen receptors in patients with postmenopausal osteoporosis.

Although all postmenopausal women are relatively estrogen-deficient, osteoporosis develops in only some of them. This could be related to a greater-than-normal degree of postmenopausal failure in sex hormone production or to a decrease in biologic effect at target tissue sites. We compared the concentration of sex steroids in serum and the concentration of cytosolic estrogen receptors in one target tissue (obtained by biopsy of the uterine cervix) in 18 women with postmenopausal osteoporosis and in 18 age-matched postmenopausal control subjects. Serum androstenedione and estrone were not significantly lower and serum estradiol was only marginally lower in the osteoporotic patients. Estrogen-receptor concentration in cervical tissue from both postmenopausal groups was not significantly different. We concluded that abnormalities of residual postmenopausal production of sex steroids and binding of sex steroids to cervical target tissue are not the major factors accounting for the decreased bone mass in women with postmenopausal osteoporosis.