Scientists may have found an antiaging hormone in mice.

The hormone is a protein naturally made by the mice. In lab tests, researchers found that mice that make a lot of that protein lived about 20 percent longer than normal mice.

But don't go looking for that hormone in a bottle yet. The study only included mice, so scientists don't know if the same is true for people.

The researchers included Makoto Kuro-O, MD, PhD, an assistant professor of pathology at the University of Texas Southwestern Medical Center in Dallas. The study appears in Science Express, the early online edition of Science.

The Fight for the Fountain of Youth

Gene Link

Why did the long-living mice make more of the protein? It comes down to a single gene called the Klotho gene, write the researchers.

There are still lots of things scientists don't know about genes, which hold DNA. But in a really simple sense, genes are like recipes. They have the instructions to make proteins the body needs to carry out its many tasks.

A typo in a gene's recipe can cause trouble. Imagine, for instance, a cookie recipe that mistakenly called for a cup of salt instead of sugar, or a meatloaf recipe that required baking for 45 hours, not 45 minutes. You'd end up with a very different result than your goal.

Aging Gracefully and Naturally

Antiaging Findings

Previously, the researchers found that a defect in the Klotho gene made mice age faster than normal. Now, they report that when the Klotho gene's recipe yielded a heaping portion of its protein, mice lived longer than normal. That's called "overexpression" of the gene.

"Klotho protein may function as an anti-aging hormone in mammals," the scientists write.

How does the hormone work? That's not yet known, but it may have something to do with insulin and insulin-like growth factor (IGF), write the researchers. Insulin is another hormone made by the body. It's used to control blood sugar. IGF signals many pathways within cells.

Meanwhile, your best bet for living longer (and better) may be taking good care of yourself.

There are many ways to do that, including buckling your seatbelt, quitting smoking, nurturing your mental health and relationships, getting screened for diseases, switching your activity and eating habits, and so on. Talk to your doctor for pointers.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Kurosu, H. Science Express, Aug. 25, 2005, online edition. News release, Science.