Fact One: Insulin receptor substrate-2 (Irs2) is a protein that sits on cell surfaces; its job is to allow those cells to respond to insulin. Fact Two: Starved mice, which have low blood levels of insulin and heightened insulin sensitivity, live longer than well-fed mice.

Given those two facts, Dr. Morris White of Harvard Medical School wanted to see if he could make mice live longer by stopping the action of Irs2 in the brain alone, thereby making the brain less able to perceive signals from insulin.

So, in that handy way that scientists have, he engineered some mice so that their nerve and brain cells lacked one of the pair of genes that makes Irs2. The resulting mice weighed about fifteen percent more than normal and were insulin resistant. In spite of those metabolic disadvantages, however, they lived about eighteen percent longer than normal lean mice, simply because their brains' exposure to insulin was limited by their lack of Irs2.

How can you engineer yourself to achieve lower Irs2 activity in your brain? Insulin exposure is what turns on Irs2, so, according to Dr. White, it might be a good idea to treat type 2 diabetes by increasing insulin sensitivity rather than by increasing insulin secretion. There are medicines to do that, of course, but the time-honored way is via our old friends: exercise and diet.

Sources: Medline Plus; ScienceNOW

Editor's Note: Studies show that skinny folks live the longest! Maybe Byetta can help type 2s achieve that healthy state of slenderosity.