Osteocalcin, known as bone gamma-carboxyglutamic acid-containing protein (BGP), is a noncollagenous protein found in bone and dentin. It has a molecular weight of 5800 Da and contains 49 amino acids. 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. 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. A role of osteocalcin in male fertility may enhance the synthesis of testosterone