Osteoporosis and mild metabolic acidosis in the rat after orchiectomy and their prevention: Should prophylactic therapy be administered to patients with androgen deprivation?

Purpose: To date there has been little research on the etiology and prophyl axis of osteopenia during androgen deprivation. This condition is gaining i ncreasing attention, partially due to the considerable osteoporosis related side effects of hormone withdrawal symptoms in patients with prostate canc er. We characterized androgen deprivation and its prophylaxis. Materials and Methods: A total of 36 male Sprague-Dawley rats underwent lap arotomy, orchiectomy or orchiectomy with subsequently treatment with calciu m acetate and sodium citrate via the water supply. Postoperative observatio n was 19 weeks. Test parameters were weight development, testosterone, para thyroid hormone, vitamin D, osteocalcin, cross links, hydroxyproline and cy clic adenosine monophosphate as well as bone density, tensile strength, min eral content and histomorphometry. Results: Animals subjected to orchiectomy had a reduction in bone mineral c ontent and fracture energy with mild metabolic acidosis. The markers of bon e metabolism were statistically unchanged, while the ratio of trabeculae-to -tissue area decreased. Animals treated with orchiectomy, calcium acetate a nd sodium citrate had moderately compensated metabolic alkalosis and increa sed bone minerals. Fracture energy was likewise normal and there was a tend ency toward higher bone metabolism. Conclusions: Castration led to a reduced increase in body mass, considerabl e standard deviation from biochemical and histological criteria for tubular bone and, thus, an increased fracture risk. A possible cause may be reduce d formation and unchanged bone loss combined with mild metabolic acidosis. Calcium and alkalization seem to be effective prophylaxis for androgen depr ivation. Considering the large number of osteoporotic complications after a ndrogen deprivation, further clinical studies are justified to show the ben efits of prophylactic therapy.