Carboxylation of Osteocalcin Affects Its Association With Metabolic Parameters in Healthy Children

  1. Abel López-Bermejo, MD1
  1. 1Pediatrics, Dr. Josep Trueta Hospital and Girona Institute for Biomedical Research, Girona, Spain;
  2. 2Primary Care Pediatrics, Catalonian Institute of Health, Figueres, Spain;
  3. 3Pediatrics, Salut Empordà Foundation, Figueres, Spain;
  4. 4Pediatric Endocrinology, Sant Joan de Déu Children's Hospital, Esplugues, Barcelona, and CIBERDEM (Center for Network Biomedical Research in Diabetes and Related Metabolic Diseases), ISCIII, Madrid, Spain;
  5. 5Department of Woman and Child, University of Leuven, Leuven, Belgium.
  1. Corresponding author: Abel López-Bermejo, alopezbermejo.girona.ics{at}gencat.cat.

Abstract

OBJECTIVE Osteocalcin (OC), a bone-derived protein, was recently shown to regulate metabolic pathways in mice. Undercarboxylated OC (ucOC), but not carboxylated OC (cOC), increases adiponectin and insulin secretion. It is unclear if carboxylation of OC affects its association with metabolic parameters in humans.

RESEARCH DESIGN AND METHODS The associations between ucOC, cOC, total and high-molecular-weight (HMW) adiponectin, and insulin secretion (homeostasis model assessment [HOMA]-β) were investigated in a population-based sample of healthy prepubertal children (n = 103; 49 boys and 54 girls).

RESULTS Weight-dependent associations were observed between the different forms of OC and metabolic parameters. Higher cOC was related to lower HMW adiponectin (with a stronger association in leaner children; P < 0.001). Higher ucOC-to-cOC ratio was associated with higher HOMA-β (P < 0.01) in leaner children and associated with higher HMW adiponectin (P < 0.001) in heavier children.

CONCLUSIONS In a weight-dependent manner, cOC and the proportion of ucOC are differentially related to HMW adiponectin and insulin secretion in healthy children.

Footnotes

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Received October 4, 2009.
    • Accepted December 9, 2009.
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This Article

  1. Diabetes Care vol. 33 no. 3 661-663
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