Association between osteocalcin gamma-carboxylation and insulin resistance in overweight and obese postmenopausal women.
J Diabetes Complications
; 31(6): 1027-1034, 2017 Jun.
Article
em En
| MEDLINE
| ID: mdl-28242268
ABSTRACT
AIM:
In mice, osteocalcin (OCN) acts as a bone-derived hormone promoting insulin sensitivity and glucose tolerance. In that species, OCN endocrine action is inhibited when its first glutamic acid residue (Glu13) is γ-carboxylated (Gla). The importance of this posttranslational modification for OCN function in human is still unclear. Our objectives were to identify an assay to assess γ-carboxylation of human OCN on its first Glu residue (Glu17) and to test its association with insulin resistance and inflammation profile in overweight women.METHODS:
Several ELISAs were tested to determine their specificity toward various forms of human OCN. Associations between OCN γ-carboxylation and determinants of glucose tolerance, insulin sensitivity, liver function and subclinical inflammation were then investigated in 129 non-diabetic overweight and obese postmenopausal women.RESULTS:
We identified assays allowing the measurement of total OCN (tOCN) and the ratio of Gla17/tOCN. Circulating Gla17/tOCN levels correlated negatively with insulin sensitivity assessed by hyperinsulinemic-euglyceamic clamp (P=0.02) or insulin sensitivity index derived from oral glucose tolerance test (P=0.00003), and positively with insulin resistance assessed by HOMA-IR (P=0.0005) and with markers of subclinical inflammation and liver enzymes, including C-reactive protein (CRP; P=0.007) and aspartate aminotransferase (AST; P=0.009).CONCLUSIONS:
γ-carboxylation of OCN on Glu17 residue correlates with insulin resistance and subclinical inflammation, suggesting that γ-carboxylation of OCN negatively regulates its endocrine action in humans.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Resistência à Insulina
/
Dióxido de Carbono
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Osteocalcina
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Pós-Menopausa
/
Sobrepeso
/
Obesidade
Tipo de estudo:
Etiology_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article