A Columbia University research team may have discovered a way to treat patients with type 2 diabetes. It has been known for some time that bone cells contain a protein called osteocalcin, produced by osteoblasts. However, its purpose was difficult to determine. This research in mice shows that osteocalcin appears to reduce the fat accumulation in fat cells and increase pancreas-produced insulin. This research also shows that the skeleton is actually an endocrine organ, emitting hormones that control the metabolism of sugar, energy, and fat. The study used mice genetically engineered without the osteocalcin gene. The mice became obese with low concentrations of insulin, causing poor control of blood glucose, similar to people with diabetes. Other mice, engineered with extra osteocalcin, remained thin even though fed a high-calorie diet. Their insulin concentrations were higher, and they were more sensitive to the insulin produced in the pancreas. Further testing showed that osteocalcin caused the pancreas to produce more insulin, store less fat in fat cells, and secrete a hormone called adiponectin. Adiponectin works to “improve cells’ sensitivity to insulin” in both mice and people. Dana T. Graves from Boston University indicated that the discovery that bone cells regulate metabolism through osteocalcin may have implications for cardiovascular disease and metabolic syndrome.
(Source: Science News Online, August 11, 2007, Volume 172, Number 6)
