[Separation and purefied of calf osteocalcin, set up radioimmunoassay for osteocalcin].

OBJECTIVE AND METHODS

We extracted and purified osteocalcin (BGP) from calf femur by gel filtration, FPLC and HPLC subsequently. The rabbits were immunized by this antigen and produced antibody. With this antibody (final 1: 35,000 dilution) we established RIA for BGP. This assay is stable and sensitive, the kd was 2.29 x 10(11). The intra assay variation was 2.1% and the inter assay variaton was 5.6%. It has no crossreaction with insulin, parathyroid hormone or calcitonin.

RESULTS

The serum BGP values were detected in normal subjects and six kinds of bone metabolic diseases. In 81 normal subjects, the average serum BGP level was (5.3 +/- 1.5) ng/ml and in postmenopausal osteoporosis the serum BGP level [(6.2 +/- 1.9) ng/ml, n = 42] was higher than the normal (P < 0.05). The serum BGP levels were increased much in primary hyperparathyroidism [(12.8 +/- 7.0) ng/ml, n = 21, P < 0.001]. Increased values of BGP were also found in patients with chronic renal failure [(8.5 +/- 2.4) ng/ml, n = 18, P < 0.01] and Paget's disease [(6.7 +/- 2.2) ng/ml, n = 12, P < 0.05]. Decreased serum BGP values were found in Cushing syndrome [(2.9 +/- 0.9) ng/ml, n = 16, P < 0.001] and hypoparathyroidism [(3.4 +/- 1.1) ng/ml, n = 42, P < 0.001]. This result showed that in diseases with high bone turnover, the serum BGP levels were increased and in diseases with low bone turnover, the serum BGP levels were decreased.

CONCLUSION

The data suggest that serum BGP is a sensitive marker for bone turnover. It is very improtant in studying bone metabolic diseases.