A HETEROGENEITY IN SERUM OSTEOCALCIN N-TERMINAL FRAGMENTS IN PAGETS-DISEASE - A COMPARISON WITH OTHER BIOCHEMICAL INDEXES IN PREMENOPAUSE AND POSTMENOPAUSE

An osteocalcin (OC) nitrogen (N)-terminal sandwich enzyme immunoassay that employs anit-N-20 (amino acids 1-20) polyclonal and monoclonal an tibodies has been developed. This assay has demonstrated the existence of a heterogeneity in the OC N-terminal fragments observed in the ser um of a patient with Paget's disease and a normal child. The elevation of the serum OC N-terminal value that occurs in Paget's disease was c onsidered to be comparable to the serum alkaline phosphatase (ALP) ele vations that also occur. The size of the peaks corresponding to N-term inal OC fragments in Paget's serum decreased 3 months after bisphospho nate treatment. Serum levels of OC N-terminals, and other biochemical indices, were determined for 67 pre menopausal and 181 postmenopausal Japanese women. Serum OC N-terminal levels increased significantly (41 .2%) in postmenopausal women compared with age-matched premenopausal w omen. These results strongly suggest that serum OC N-terminal levels r eflect bone turnover rates when bone resorption is dominant.