Serum prolidase activity in postmenopausal osteoporosis

Prolidase is a specific imidodipeptidase involved in collagen degradation. The increase in the enzyme activity is believed to be correlated with increased intensity of collagen degradation and may be a useful tool in diagnosis and/or monitoring osteoporosis. The study aimed to evaluate serum prolidase activity in postmenopausal osteoporosis and its relation with several metabolic bone markers.

Sixty-one postmenopausal women with menopause times = or >1 year without any hormone replacement treatment were recruited in this study. Bone mineral density (BMD) was obtained from antero-posterior spine L2-L4 and femoral neck scanning with dual energy X-ray absorptiometry (DXA). Thirty-one subjects with T scores lower than -2.5 were accepted as osteoporotic and control group consisted of 30 subjects. Urinary deoxypyridinoline (Dpd), calcium, creatinine, serum total calcium, phosphorus (Pi), alkaline phosphatase, parathyroid hormone levels and prolidase activity were analysed with colorimetric or immunochemical

Serum prolidase activity was neither significantly different in osteoporosis nor correlate with other bone turnover markers. Urinary Dpd/creatinine and serum Pi levels of postmenopausal osteoporotic group were significantly higher than in the control group.

Serum prolidase activity does not correlate with BMD in postmenopausal osteoporosis with menopause time over 1 year. However, its role during premenopausal accelerated decrease in BMD is not established yet.