Osteocalcin

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Bone gamma-carboxyglutamate (gla) protein
Osteocalcin 1Q8H.png
PDB rendering based on 1q8h.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols BGLAP ; BGP; OC; OCN
External IDs OMIM112260 MGI88156 HomoloGene104130 GeneCards: BGLAP Gene
Orthologs
Species Human Mouse
Entrez 632 12095
Ensembl ENSG00000242252 ENSMUSG00000074489
UniProt P02818 P54615
RefSeq (mRNA) NM_199173 NM_031368.4
RefSeq (protein) NP_954642 NP_112736.3
Location (UCSC) Chr 1:
156.21 – 156.21 Mb
Chr 3:
88.37 – 88.37 Mb
PubMed search [1] [2]
Not to be confused with Osteonectin or Osteopontin.

Osteocalcin, also known as bone gamma-carboxyglutamic acid-containing protein (BGLAP), is a noncollagenous protein found in bone and dentin. Because it has gla domains, its synthesis is vitamin K dependent. In humans, the osteocalcin is encoded by the BGLAP gene.[1][2] Its receptor is GPRC6A.[3]

Function[edit]

Osteocalcin is secreted solely by osteoblasts and thought to play a role in the body's metabolic regulation and is pro-osteoblastic, or bone-building, by nature.[4] It is also implicated in bone mineralization and calcium ion homeostasis. Osteocalcin acts as a hormone in the body, causing beta cells in the pancreas to release more insulin, and at the same time directing fat cells to release the hormone adiponectin, which increases sensitivity to insulin.[4]

Osteocalcin acts on Leydig cells of the testis to stimulate testosterone biosynthesis and therefore affect male fertility.[5]

Use as a biochemical marker for bone formation[edit]

As osteocalcin is produced by osteoblasts, it is often used as a marker for the bone formation process. It has been observed that higher serum-osteocalcin levels are relatively well correlated with increases in bone mineral density (BMD) during treatment with anabolic bone formation drugs for osteoporosis, such as Teriparatide. In many studies, osteocalcin is used as a preliminary biomarker on the effectiveness of a given drug on bone formation. For instance, one study which aimed to study the effectiveness of a glycoprotein called lactoferrin on bone formation used osteocalcin as a measure of osteoblast activity.[6]

References[edit]

  1. ^ Puchacz E, Lian JB, Stein GS, Wozney J, Huebner K, Croce C (May 1989). "Chromosomal localization of the human osteocalcin gene". Endocrinology 124 (5): 2648–50. doi:10.1210/endo-124-5-2648. PMID 2785029. 
  2. ^ Cancela L, Hsieh CL, Francke U, Price PA (Sep 1990). "Molecular structure, chromosome assignment, and promoter organization of the human matrix Gla protein gene". The Journal of Biological Chemistry 265 (25): 15040–8. PMID 2394711. 
  3. ^ Pi M, Wu Y, Quarles LD (Jul 2011). "GPRC6A mediates responses to osteocalcin in β-cells in vitro and pancreas in vivo". Journal of Bone and Mineral Research 26 (7): 1680–1683. doi:10.1002/jbmr.390. PMID 21425331. 
  4. ^ a b Lee NK, Sowa H, Hinoi E, Ferron M, Ahn JD, Confavreux C et al. (Aug 2007). "Endocrine regulation of energy metabolism by the skeleton". Cell 130 (3): 456–69. doi:10.1016/j.cell.2007.05.047. PMC 2013746. PMID 17693256. 
  5. ^ Karsenty G, Oury F (Jan 2014). "Regulation of male fertility by the bone-derived hormone osteocalcin". Molecular and Cellular Endocrinology 382 (1): 521–6. doi:10.1016/j.mce.2013.10.008. PMC 3850748. PMID 24145129. 
  6. ^ Bharadwaj S, Naidu AG, Betageri GV, Prasadarao NV, Naidu AS (Sep 2009). "Milk ribonuclease-enriched lactoferrin induces positive effects on bone turnover markers in postmenopausal women". Osteoporosis International 20 (9): 1603–11. doi:10.1007/s00198-009-0839-8. PMID 19172341. 

Further reading[edit]

External links[edit]