Nyctohemeral changes in bone turnover assessed by serum bone Gla-protein concentration and urinary deoxypyridinoline excretion: effects of growth and ageing

Abstract

1. To investigate whether there is a nyctohemeral rhythm in bone turnover, we measured serum bone Gla-protein (osteocalcin, an index of osteoblast activity) concentration every 2h and urinary deoxypyridinoline (a marker of bone collagen resorption) excretion for 8h periods in 10 pubertal girls (aged 10-14 years), 15 premenopausal women (aged 20-49 years) and 17 postmenopausal women (aged 50-75 years). 2. The serum concentration of bone Gla-protein and the urinary excretion of deoxypyridinoline were five times higher in the pubertal girls than in the premenopausal women. The urinary excretion of deoxypyridinoline in the postmenopausal women was twice that in the premenopausal women. 3. There was a nyctohemeral pattern in all age groups with mean night-time increases of 28% (P < 0.001) in the urinary excretion of deoxypyridinoline and of 5% (P < 0.001) in the serum bone Gla-protein concentration. 4. There also were nyctohemeral patterns in the urinary excretion of calcium (P < 0.02), sodium (P < 0.001) and potassium (P < 0.001), with decreases at night. There was a negative correlation between the night-time changes in the urinary excretion of deoxypyridinoline and calcium, especially in adult women (P < 0.01). 5. The serum level of parathyroid hormone increased with age, but this effect was only observed at night (01.00 to 07.00 hours). There was a nyctohemeral rhythm of the serum intact parathyroid hormone level at all ages, with a peak in the afternoon and night. 6. Thus, at night, there is a large increase in bone resorption and a small increase in osteoblastic activity, representing a nyctohemeral rhythm of bone turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

Dynamics of bone turnover in children with GH deficiency treated with GH until final height

“…Indeed, OC, PICP, and ICTP levels follow a similar circadian rhythm with peak values occurring in early morning and nadirs in the afternoon (1,30,37). Circadian variation in bone markers appears to be unaffected by age and sex (38), as well as by growth and ageing (39). Furthermore, in children with GHD, we previously demonstrated that both nocturnal and diurnal 12-h mean data for OC and PICP were significantly lower than controls, but the pattern of their circadian rhythms was maintained (30).…”

Inadequacies of glucocorticoid replacement and improvements by physiological circadian therapy

“…Circadian variation of bone remodelling is shown by levels of markers of bone resorption (urinary excretion of urinary cross-linked N-telopeptide of type 1 collagen (NTx) (40) and pyridinium cross-links (41,42)) and formation (serum osteocalcin, respectively (43, 44)): peak levels occur at night with a nadir in the afternoon. The levels of osteocalcin fall following the rise in serum cortisol, with a latency w4 h (45).…”

Circasemidian rather than circadian variation of circulating osteoprotegerin in clinical health

“…Bone turnover in laboratory animals and humans reportedly undergoes a circadian rhythm, with bone resorption and, to a lesser extent, bone formation increasing at night [1][2][3]. Such rhythms have clinical implications for the timing of sample collection and for the assessment of a given therapeutic intervention.…”