Implication of serum steroid receptor coactivator-3 level for lumbar bone mineral density and bone turnover in postmenopausal women.

BACKGROUND: Steroid receptor coactivator-3 (SRC-3) is a member of the steroid receptor coactivator family, and it can promote proliferation and differentiation in human osteoblasts by modulating estrogen receptor activity. Previous studies have reported that allelic variation at the SRC-3 locus is significantly positively correlated with the lumbar bone mineral density in Caucasian men, but the relationship between SRC-3 and bone metabolism in postmenopausal women remains unknown. OBJECTIVE: To investigate the level of serum SRC-3 in postmenopausal women and its association with bone mineral density and bone turnover markers. METHODS: Fifty-five women with postmenopausal osteoporosis and 35 healthy postmenopausal women were recruited, and their serum levels of SRC-3, 25-hydroxyvitamin D, osteocalcin and procollagen I N-terminal peptide, beta C-terminal telopeptide of type I collagen were detected. The bone mineral density of L1-4 vertebrae and femoral neck were measured by dual-energy X-ray absorptiometry. RESULTS AND CONCLUSION: Serum SRC-3 level in postmenopausal women with osteoporosis was remarkably lower than that in healthy individuals. In addition, the serum SRC-3 level was positively correlated with lumbar bone mineral density, and negatively correlated with procollagen I N-terminal peptide and osteocalcin in postmenopausal women with osteoporosis. These results indicate that low serum SRC-3 level may be involved in the pathogenesis of postmenopausal osteoporosis and play a pivotal role in bone turnover. [ABSTRACT FROM AUTHOR]