Changes in urinary excretion of deoxypyridinoline in tail-suspended rats: effects of a bisphosphonate, YH529.
Urinary excretion of deoxypyridinoline (D-Pyr) has been shown to be a useful marker for bone resorption. In this study, we investigated whether D-Pyr could be used to monitor the changes in bone resorption of the hind limb induced by tail-suspension. Male Wistar rats 5-weeks old were tail-suspended in a metabolic cage to unload the hind limbs. The control rats were not suspended. YH529 (YH), an inhibitor of bone resorption, or a vehicle (phosphate buffered saline=PBS) was administered daily starting 3 days before the commencement of tail-suspension. In the non-suspended rats receiving PBS, urinary excretion of D-Pyr did not show any significant change during the one-week experimental period. In the non-suspended rats receiving YH, D-Pyr excretion significantly decreased on day 5 and 7 when compared with that observed on day 0, in accordance with the systemic inhibition of bone resorption by YH. In the tail-suspended rats receiving PBS, D-Pyr excretion showed a tendency to increase on day 1, which is in agreement with our previous report that tail-suspension causes an early (on day 1 of suspension) and transient increase in bone-resorption of the hind limbs. In the tail-suspended rats treated with YH, the increase in D-Pyr excretion on day 1 was not observed, and a significantly lower excretion was noted from day 3 to 7 during the tail-suspension. It was suggested that D-Pyr excretion might reflect the transient increase in hind limb bone resorption induced by tail-suspension. As observed in-YH treated rats, D-Pyr excretion could serve as a good marker for the inhibition of systemic bone resorption.
Ohmori
S
S
Department of Endocrinology and Metabolism, Division of Molecular Adaptation, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
Kurokouchi
K
K
Kanda
K
K
Kawano
S
S
Ito
T
T
Inazu
M
M
Kambe
F
F
Seo
H
H
D000596:Amino Acids / Q000187:drug effects* / Q000378:metabolism / Q000652:urine; D000818:Animals; D015415:Biomarkers; D001862:Bone Resorption / Q000378:metabolism / Q000517:prevention & control*; D004164:Diphosphonates / Q000494:pharmacology*; D019417:Hindlimb Suspension; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018544:Weightlessness Countermeasures; D018474:Weightlessness Simulation
D000596:Amino Acids; D015415:Biomarkers; D004164:Diphosphonates; D007093:Imidazoles; C087958:YM 529; C036020:deoxypyridinoline