Measurement of Osteocalcin

Endocrine Actions of Osteocalcin

Osteocalcin is the most abundant noncollagenous protein of bone matrix. Once transcribed, this protein undergoes posttranslational modifications within osteoblastic cells before its secretion, including the carboxylation of three glutamic residues in glutamic acid, which is essential for hydroxyapatite binding and deposition in the extracellular matrix of bone. Recent provocative data from expe...

Measurement of a more stable region of osteocalcin in serum by ELISA with two monoclonal antibodies.

Intact human osteocalcin purified from femoral bones as well as tryptic fragments of the intact molecule [amino acids (aa) 1-19, 20-43, and 45-49] were used to raise and screen monoclonal antibodies (MAbs). A two-site ELISA for measurement of human osteocalcin in serum was developed with use of these MAbs. A MAb recognizing midregion human osteocalcin (aa20-43) was used as capture antibody, and...

Six osteocalcin assays compared.

We evaluated comparatively six commercially available osteocalcin kits: ELSA-OST-NAT IRMA (CIS), ELSA-Osteo IRMA (CIS), Osteocalcin IRMA (Nichols), OSTK-PR RIA (CIS), OSCA Test Osteocalcin RIA (Henning), and Osteocalcin RIA (Nichols). All of them presented acceptable values of variance, sensitivity, and serial dilutions. However, only the ELSA-OST-NAT, ELSA-Osteo, and OSCA Test kits had analyti...

Homologous radioimmunoassay of human osteocalcin.

Osteocalcin or bone gamma-glutamic acid-containing protein (GLA protein) was isolated from human bone and used to develop a homologous radioimmunoassay of human osteocalcin. The effect of age on serum osteocalcin was studied in 380 normal children and adolescents and 330 normal adults. The mean (+/- SD) values in adults were higher in men [25 +/- 5 micrograms/L (4.3 +/- 0.8 nmol/L)] than in pre...

Imaging using osteocalcin-luciferase.