The effect of acute exercise on undercarboxylated osteocalcin and insulin sensitivity in obese men

Itamar Levinger, George J Jerums, Nigel Keith Stepto, Lewan Parker, Fabio R Serpiello, Glenn K McConell, Mitchell Anderson, David L Hare, Elizabeth Byrnes, Peter Robert Ebeling, Ego Seeman

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Abstract

Acute exercise improves insulin sensitivity for hours after the exercise is ceased. The skeleton contributes to glucose metabolism and insulin sensitivity via osteocalcin (OC) in its undercarboxylated (ucOC) form in mice. We tested the hypothesis that insulin sensitivity over the hours after exercise is associated with circulating levels of ucOC. Eleven middle-aged (58.1?2.2 years mean?SEM), obese (body mass index [BMI]=33.1?1.4 kg/m2) nondiabetic men completed a euglycemic-hyperinsulinemic clamp at rest (rest-control) and at 60 minutes after exercise (4?4 minutes of cycling at 95 of HRpeak). Insulin sensitivity was determined by glucose infusion rate relative to body mass (GIR, mL/kg/min) as well as GIR per unit of insulin (M-value). Blood samples and five muscle biopsies were obtained; two at the resting-control session, one before and one after clamping, and three in the exercise session, at rest, 60 minutes after exercise, and after the clamp. Exercise increased serum ucOC (6.4?2.1 , p=0.013) but not total OC (p>0.05). Blood glucose was lower and insulin sensitivity was 35 higher after exercise compared with control (both p
Original languageEnglish
Pages (from-to)2571 - 2576
Number of pages6
JournalJournal of Bone and Mineral Research
Volume29
Issue number12
DOIs
Publication statusPublished - 2014

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