The effect of timing of teriparatide treatment on the circadian rhythm of bone turnover in postmenopausal osteoporosis.

Background: We hypothesized that with the administration of teriparatide (TPTD) treatment at different times, we would be able to modify the physiological circadian rhythm of bone turnover.

Methods: The concentration of serum C-terminal telopeptide of collagen type I (βCTX), serum N-terminal propeptide of procollagen type I (P1NP), serum ionized calcium (iCa), and plasma PTH were measured every 3 h over a 24 h period in 14 postmenopausal osteoporotic women (aged 72.4±9.