ObjectiveTo investigate the effect of rhPTH (1-34) and elcatonin on bone metabolism and serum secreted protein acidic and rich in cysteine ( SPARC ) in postmenopausal women with osteoporosis.Methods One hundred and twenty-four postmenopausal women with osteoporosis were randomly divided into 2 groups:One group was treated with recombinant human parathyroid hormone ( 1-34 ) [ rhPTH ( 1-34 ) ] 200 U/d by subcutaneous injection (PTH group,n =89 )and another group was treated with elcatonin 20 U/week by intramuscular injection (CT group,n =35 ) for 12 months.All patients received a basic therapy with oral calcium ( Ca 600 mg+ Vit D3125 U,q..d.).The bone mineral density ( BMD ) of lumbar spine( L2-4 ),the left femoral neck,greater trochanter,and Ward's triangle,serum calcium and phosphate were measured by baseline,6 months' and 12 months.Levels of serum bone-specific alkaline phosphatase( BSAP),serum secreted protein acidic and rich in cysteine (SPARC)were determined by an ELISA assay.ResultsBy 12 months,rhPTH ( 1-34 ) treatment significantly increased the lumbar spine L2-4 BMD 7.9％ (P＜0.05),serum calcium 8.3 ％ ( P＜ 0.05 ),serum BSAP 93.4％ ( P＜ 0.05 ),serum SPARC by 12.6％[ ( 195.68±59.57 vs 173.81 ±81.33 ) pμg/L,P＜0.05 ].Elcatonin therapy increased the lumbar spine L2-4 BMD by 3.2％ (P＜0.05) at the end of 12 months,but elcatonin did not influence serum calcium,BSAP and SPARC.The rhPTH( 1-34 ) increased lumbar spine L2-4 BMD more than elcatonin did at 12 months( P＜0.05 ).ConclusionrhPTH (1-34) could promote the bone anabolism more effectively than elcatonin did.Serum SPARC may play an important role in promoting osteogenesis by rhPTH.