Comparative effects of bicalutamide (Casodex) versus orchidectomy on bone mineral density, bone remodelling, and bone biomechanics in healthy rats.
BACKGROUND
The aim of this work was to analyze the effects produced on bone mineral density (BMD) by the administration of bicalutamide and to compare them with those produced by orchidectomy. Bone formation rate (serum osteocalcin), bone resorption (serum carboxyterminal telopeptide of collagen I; CTX), and biomechanical properties of bone were also studied.


METHODS
Thirty-eight male Wistar rats were used: (1) Sham group, rats sham operated at 16 weeks of age; (2) OQX group, rats orchidectomized at 16 weeks of age, and (3) Bic group, rats sham operated at 16 weeks of age and treated during 6 weeks with bicalutamide. The rats were sacrificed at 22 weeks of age, and the BMD in femur and lumbar spine was determined. Serum osteocalcin and serum CTX were also analyzed. Biomechanical parameters related to torsion assay were also studied.


RESULTS
The OQX group showed a significant decrease in femoral BMD with respect to Sham rats, whereas bicalutamide treatment did not produce any significant change in BMD. Both Sham and Bic groups showed similar serum osteocalcin and CTX values, whereas OQX rats presented higher osteocalcin and CTX levels than the Sham group. The OQX group showed a significant decrease in femoral thickness. No significant differences were observed in the rest of the biomechanical parameters between groups.


CONCLUSIONS
These results indicate that bicalutamide treatment, in spite of its anti-androgenic properties, does not affect bone remodelling nor BMD in male healthy rats, suggesting that this compound may function as a selective androgen receptor modulator for effects on bone remodelling in the osteoblasts.
Lefort
Mar
M
Biochemistry Laboratory, Bone Pathophysiology Section, Madrid, Spain.
Díaz Curiel
Manuel
M
Carrascal
María-Teresa
MT
Méndez-Dávila
Cioly
C
de la Piedra
Concepción
C
D000726:Androgen Antagonists / Q000494:pharmacology*; D000813:Anilides / Q000494:pharmacology*; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects*; D016723:Bone Remodeling / Q000187:drug effects*; D001862:Bone Resorption; D001842:Bone and Bones / Q000187:drug effects / Q000502:physiology; D008297:Male; D023421:Models, Animal; D009570:Nitriles; D009919:Orchiectomy; D010012:Osteogenesis / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D014105:Tosyl Compounds
D000726:Androgen Antagonists; D000813:Anilides; D009570:Nitriles; D014105:Tosyl Compounds; C053541:bicalutamide