A new study published in the August 10 issue of Cell indicates that the skeleton is not just for structural support, but also helps control sugar metabolism and weight and is thus a major determinant of the development of type 2 diabetes. Apparently, bone cells release a hormone called osteocalcin, which controls the regulation of blood sugar (glucose) and fat deposition through synergistic mechanisms previously not recognized.

The researchers found that osteocalcin, a protein made only by bone-forming cells (osteoblasts), was not a mere structural protein, but rather a hormone with totally unanticipated and crucial functions. Osteocalcin directs the pancreas' beta cells, which produce the body's supply of insulin, to produce more insulin. At the same time, osteocalcin directs fat cells to release a hormone called adiponectin, which improves insulin sensitivity. This discovery showed for the first time that one hormone has a synergistic function in regulating insulin secretion and insulin sensitivity, and that this coordinating signal comes from the skeleton. Additionally, osteocalcin enhances the production of insulin-producing beta cells, which is considered one of the best, but currently unattainable, strategies to treat diabetes.

These findings suggest that altering the activity osteocalcin could be an effective therapy against type 2 diabetes. Researchers are now examining the role of osteocalcin in the regulation of blood sugar in humans and are continuing investigations into the relationship between osteocalcin and the appearance of type 2 diabetes and obesity.

Image Credit: CUMC