| Theme |
Progress in bone metabolic markers |
| Title |
Osteocalcin |
| Author |
Junya Shimizu |
Department of Pediatrics, Okayama University Graduate School of Medicine and Dentistry |
| Author |
Hiroyuki Tanaka |
Department of Pediatrics, Okayama University Graduate School of Medicine and Dentistry |
| [ Summary ] |
Osteocalcin (OC) is one of the non-collagenous proteins found in bone, which is synthesized by osteoblasts and odontoblasts. This bone specific protein contains three residues of vitamin K-dependent amino acid, gamma-carboxyglutamic acid (Gla), which facilitate the binding of osteocalcin to hydroxyapatite in bone. The blood levels of osteocalcin are used as one of sensitive markers of bone formation, and reflect the underlying bone histology in renal osteodystrophy. Because OC varies physiologically and the intact form of OC is unstable, we must be careful on treatment of samples and the interpretation of the measured values. Recent reports have shown that undercarboxylated OC (uc-OC) is predictive of hip fracture risk. The measurement of a bone marker like uc-OC may provide us with more useful information in the assessment of bone turnover. |