In a study on mice engineered to produce a protein showed that a specific brain region, called the hypothalamus governs aging and longevity.
The researchers found that mice engineered to have their brains produce more SIRT1, a protein known to play a role in aging and longevity, tend to be more active after a two-day fast than those who don't produce the protein.
They explained that the mice with increased brain SIRT1 have internal mechanisms that make them use energy more efficiently, which helps them move around in search of food even after a long fast.
"This result surprised us. It demonstrates that SIRT1 in the brain is tied into a mechanism that allows animals to survive when food is scarce. And this might be involved with the lifespan-increasing effect of low-calorie diets," said the study's senior author Dr. Shin-ichiro Imai, an expert in aging research at Washington University School of Medicine in St. Louis.
Imai's past research demonstrated that SIRT1 is at the center of a network that connects metabolism and aging. A form of the gene is found in every organism on earth.
The gene coordinates metabolic reactions throughout the body and manages the body's response to nutrition. SIRT1 is activated under low-calorie conditions, which have been shown to extend the life spans of laboratory animals.
The researchers found that the key to the mice's extra activity lies in a small region of the brain called the hypothalamus, which controls basic life functions such as hunger, body temperature, stress response and sleep-wake cycles.
"This is the first time that it has been demonstrated that SIRT1 is a central mediator for behaviour adaptation to low-calorie conditions," said a co-author of the study.
The study suggests that the brain, and particularly the hypothalamus, might play a dominant role in governing the pace of aging.
They believe their studies could eventually provide clues for increasing productive aging in people.
"If we can enhance the function of the human hypothalamus by manipulating SIRT1, we could potentially overcome some health problems associated with aging. One example is anorexia of aging in which elderly people lose the drive to eat. It is possible that enhancing SIRT1 could alleviate behavioral problems like this," said Imai.
The research findings are published in the latest issue of the Journal of Neuroscience.