Measurements of Gamma-Carboxyglutamate and Circulating Osteocalcin in Normal Children and Adults

Clin Chim Acta. 1983 Feb 28;128(1):1-8. doi: 10.1016/0009-8981(83)90049-9.

Abstract

We have measured serum osteocalcin by radioimmunoassay, and urinary gamma-carboxyglutamic acid (Gla) by Dowex-1 chromatography in healthy adults and children. Circulating osteocalcin is 6.8 +/- 0.5 and 5.8 +/- 0.5 ng/ml in adult males (n = 25) and females (n = 26), respectively. Values are higher in children (n = 26), ranging from 25-30 ng/ml in a 1-year-old and declining to the adult level at puberty. The ratio of urinary Gla/creatinine as a function of age parallels the pattern of serum osteocalcin. Free Gla ranges from a high of 150 +/- 20 mumol Gla/g creatinine in infants (n = 17), decreasing until puberty at which time the excretion stabilizes at 44 +/- 4 mumol Gla/g creatinine (n = 27). The greater amounts of circulating osteocalcin and urinary Gla most likely reflect synthesis of osteocalcin during growth. With epiphyseal closure, levels decline and, in the adult, probably represent normal bone remodelling.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 1-Carboxyglutamic Acid / immunology
  • 1-Carboxyglutamic Acid / urine*
  • Adult
  • Aging
  • Antibody Specificity
  • Calcium-Binding Proteins / blood*
  • Calcium-Binding Proteins / immunology
  • Child
  • Female
  • Glutamates / urine*
  • Humans
  • Male
  • Osteocalcin
  • Radioimmunoassay / methods
  • Reference Values

Substances

  • Calcium-Binding Proteins
  • Glutamates
  • Osteocalcin
  • 1-Carboxyglutamic Acid