The knee bone’s connected to the… pancreas bone?

PhysOrg blows our minds with the discovery that our skeletons are actually endocrine glands:

Karsenty and his colleagues had previously shown that leptin, a hormone released by fat cells, acts upon and ultimately controls bone mass. They reasoned that bones must in turn communicate with fat, so they searched bone-forming cells for molecules that could potentially send signals back to fat cells.

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.

Crazy. There’s a cure for type 2 diabetes hiding somewhere in the way bones talk to fat.