We may be one step closer to discovering the fountain of youth.
Scientists have discovered a gene that produces a hormone that raises the life expectancy in mice by 30 percent. Humans also have this gene, dubbed "Klotho," after the Greek goddess who spins the thread of life.
Scientists had observed that mice with a defective Klotho gene aged prematurely and wondered if an enhanced gene would have an opposite effect.
The scientists involved in a study led by Makoto Kuro-o of the University of Texas's Southwestern Medical Center at Dallas created mice with a revved up Klotho gene. Those mice lived 30 percent longer. Next, the scientists injected the hormone into normal mice, and evidence suggests those mice will live longer too.
"The hope is that the same thing that was true for those mice will also be true for people," said Dr. David Katz, ABC News medical contributor. "We know the Klotho gene and hormone exist in humans, so it's reasonable to assume that it could help humans live longer."
This study, published in Science journal, has identified a hormone that is naturally produced and found in the bloodstream -- which has people dreaming of a "fountain of youth" shot.
Yet, only between 1 percent and 10 percent of studies in animal research translate to humans, according to Katz. There are signs that the Klotho hormone could cause insulin resistance, which would mean it wouldn't work for humans, he added.
"Insulin resistance may not be a huge problem for mice, but it's a huge health issue for humans, and ultimately that could be too high a price to pay," he said.
But even if all goes well, it will be years before a life-lengthening injection will be available.
"Ordinarily, it would take between 15 and 20 years to develop a drug like this. But science is accelerating all the time," Katz said.