Serum Osteocalcin in 1634 Healthy Children

Abstract

Osteocalcin or bone Gla protein (BGP) is a vitamin K-dependent, low-molecular-mass (5800 Da), 49 amino acid peptide synthesized by osteoblasts (1)(2). Osteocalcin contains three residues of γ-carboxyglutamate, which provide the point of interaction between the BGP and hydroxyapatite in the extracellular bone matrix. The 19–20 and 43–44 residues provide sites for the tryptic hydrolysis; the resulting peptides may be the products of liver, kidney, and plasmatic breakdown of the molecule. The physiological role of these fragments is unknown. Osteocalcin is an important marker of bone turnover in physiological and pathological conditions (3). Physiologically, serum osteocalcin was increased in children, particularly during the first year of life and during puberty, when the evolution of the concentration was related to the rapidity of physical growth. The significant correlation between BGP and testosterone and serum insulin-like growth factor 1 is consistent with …