the effects of chemical castration with degarelix on bone turnover: densitometric and biomechanics bone properties of male rats

Background: gonadotropin releasing hormone (gnrh) antagonists may cause chemical castration in males by suppressing the pituitary-gonadal axis, hence reducing testosterone level. there are limited data on the effects of degarelix, a newer series of potent and long acting gnrh antagonist on bone. objectives: the current study aimed at determining the effects of degarelix on bone turnover, bone densitometry, and bone mechanical strength in male rats. methods: eighteen male sprague-dawley rats were randomly divided into sham (sham), orchidectomized (orx), and degarelixinduced (dgx) groups. chemical castration was performed by subcutaneous degarelix injection (2 mg/kg) at the scapular region. the rats were scanned for baseline bone mineral area (bma), bone mineral content (bmc), and bone mineral density (bmd) using dual-energy x-ray absorptiometry (dxa). following six weeks of experimental period, bma, bmc, and bmd were measured again with dxa and blood was collected for testosterone and bone biomarkers (osteocalcin and c-terminal of type i collagen crosslink (ctx-1)) measurements. the rats were euthanized and femora were dissected for bone biomechanical strength analysis. results: bilateral orchidectomy and degarelix administration significantly lowered serum testosterone level, decreased whole body bmc, femoral bma, femoral bmc, and femoral bmd (p < 0.05) compared with the sham group. however, no significant changes were observed in bone biochemical markers and bone mechanical strength in all experimental groups. conclusions: in conclusion, degarelix administration had comparable effects on bone as bilateral orchidectomy. administration of degarelix provides an alternative method of inducing testosterone deficient-osteopenia in male rats without need for removing the testes.