EFFECT OF SALMON-CALCITONIN ON FEMORAL BONE QUALITY IN ADULT OVARIECTOMIZED EWES

The aim of this study was to evaluate the effect of intermittent calci tonin on femoral bone quality in adult ewes from the time of ovariecto my. Six months after the start of the experiment, bone density measure ments and mechanical testing (torsion and resonant frequency analysis of the diaphysis and compression of an excised trabecular bone cylinde r from the femoral neck) were performed in sham-control and ovariectom ized (OVX) ewes treated with placebo or salmon calcitonin (50 or 100 u nits, 3 times/week). Crystallinity of bone was evaluated by measuring X-ray diffraction line broadening. After OVX, a nonsignificant bone lo ss was found at all measured sites in the femur (-3 to -9%) together w ith a decreased biomechanical competence in the trabecular bone (compr essive strain -28%, P < 0.05). Treatment with salmon calcitonin, 50 or 100 IU subcutaneously three times a week from the time of ovariectomy , resulted in a significant dose-dependent preservation of bone streng th in the trabecular bone of the femoral neck compared with OVX. No ad verse effects of calcitonin were observed on bone crystal composition as assessed by diffractiometry. We conclude that in adult ewes intermi ttent calcitonin treatment from the time of OVX was associated with a significant preservation of cancellous bone strength and strain in tra becular bone of the femoral neck, without affecting crystalline proper ties of bone.