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Kaneki M: [Is ucOC a novel bone-derived anti-diabetogenic hormone in humans?] . Clin Calcium. 2009 Sep;19(9):1304-10.
Recent studies have indicated that osteocalcin, a peptide secreted by osteoblasts, functions as an anti-diabetogenic hormone in mice. Osteocalcin knock out mice exhibit obesity, hyperglycemia, and decreased insulin secretion relative to wild-type mice. Treatment with non-carboxylated osteocalcin upregulates energy expenditure, and ameliorates obesity and diabetes in mouse models of obesity-related diabetes. Of interest, the beneficial effects of osteocalcin were shown to be specific to non-carboxylated osteocalcin. This appears, however, inconsistent with recent clinical studies showing insulin-sensitizing effects of vitamin K, which promotes gamma-carboxylation of osteocalcin. These findings shed new light on the crosstalk between bone and energy expenditure, and lead to new questions. These questions include: (1) Does non-carboxylated osteocalcin exert the beneficial effects in humans?; (2) Does warfarin, a vitamin K antagonist, improve insulin, sensitivity and lower blood glucose levels?; (3) and Do estrogen and bisphosphonate, which reduce circulating osteocalcin, contribute to insulin resistance and obesity? These issues await further investigations. |
86(1,1,1,6) |