Wouldn't you like to have a drug that reduces insulin resistance, increases insulin production, makes your beta cells grow, and keeps you from getting fat?
Me too. And guess what. We may already have such a "drug" in our bodies, osteocalcin.
Osteocalcin is produced by your bones. More specifically, it's produced by bone cells called osteoblasts. Those are the bone cells that build new bone and make your bones stronger.
Osteocalcin is thought to be involved with laying down the new bone, although the mechanism is not entirely clear. In this case, osteocalcin works within the bone itself.
But until recently, no one had any idea that the bones could also produce a hormone, meaning a substance that is produced in one part of the body and travels through the bloodstream to affect other parts of the body, in this case beta cells and fat cells. But apparently that's what the bones are doing.
Osteocalcin produced by the bone seems to be regulating blood sugar levels. One surprising thing about the effects of osteocalcin is that it seems to increase insulin production at the same time it decreases insulin resistance. Usually when something reduces insulin resistance, it also reduces insulin production.
Not only does the osteocalcin regulate blood sugar levels, but it also keeps fatty acid levels in the blood low, makes animals use more energy, and keeps them from getting fat.
So far, this all sounds miraculous. However, the research, done by Gerard Karsenty of Columbia University and coworkers, was done in mice. And we all know how many times mice have been cured of diabetes without anyone being able to translate this research into useful treatments for humans.
Nevertheless, this is exciting research. I won't detail the many elegant experiments done by the Karsenty group to give good evidence of what is going on in the mice. If you want the science behind the results, you can read the full text of the paper here.
Their discoveries came about because they applied the concept of reciprocity, or feedback loops. In general, if one substance stimulates the production of another substance, when the second substance increases sufficiently, it feeds back and inhibits further synthesis.
For example, low blood glucose levels stimulate the synthesis and secretion of insulin. When insulin levels rise sufficiently, they feed back to inhibit further synthesis and secretion.
The Karsenty group were familiar with leptin, a hormone produced by fat cells. Leptin tells the rest of the body how much fat you're carrying around. Obviously, if you're carrying a lot of fat, you're heavier, and you need stronger bones. Hence leptin acts on the osteoblasts to make them produce stronger bones.
The Karsenty group reasoned that if a product of the fat cells stimulated bone cells, most likely the bone cells would produce a substance that fed back to inform the fat cells of their situation. So they started to look for such a compound. And they identified osteocalcin as the key. People with type 2 diabetes tend to have low levels of osteocalcin, and those levels increase as they get their blood glucose levels controlled.
