C-telopeptide(CTX) is an RIA based on monoclonal antibody raised against this 8-amino-acid sequence was developed. C-telopeptide(CTX) represents a valuable tool for assessing bone resorption. The study shows C-telopeptide(CTX) ELISA exhibited acceptable analytical performance and sufficient discriminatory power to show expected directional changes in the rate of bone resorption following ovariectomy, ovx plus estradiol or alendronate treatment, and administration of a calcium-deficient diet.