An enzyme found in the brain that may pave way for obesity treatment, has been identified by scientists from Brown University, Rhode Island Hospital, and the University of Texas Southwestern Medical Centre.
The Sirt1 enzyme in the body has generated enormous attention as a possible secret to living longer.
They found that inhibiting the activity of Sirt1 in the brain's hypothalamic region appears to help control food intake - something that provides ground for new treatments for obesity.
It suggests that Sirt1 behaves differently in the brain than in organs such as the liver and pancreas, where the enzyme has been more commonly studied.
Researchers have shown that fasting activates Sirt1 and thereby helps extend life.
Drug companies and scientists have also thrown their support behind resveratrol, a compound found in red wine, thought to be beneficial to the body because it may activate Sirt1.
The new Brown research challenges at least some of the preexisting findings, because scientists found that inhibiting the activity of Sirt1 in the brains of rats, rather than stimulating it, appeared to reduce appetite, leading to a smaller weight gain compared to untreated animals. They believe a similar mechanism exists in human brains.
"It's still controversial whether calorie restriction or resveratrol are Sirt1 stimulators," said Eduardo Nillni, the study's lead author. Nillni is professor of medicine (research) at the Warren Alpert Medical School of Brown University and a member of the Department of Molecular Biology, Cell Biology and Biochemistry.
The team did find that fasting helped increase Sirt1 production and activity in the brain, consistent with the view that reducing food intake stimulates Sirt1 elsewhere in the body.
But they generated clear data showing that pharmacologically or genetically inhibiting Sirt1 activity in the brain led to the animals eating less food and gaining fewer pounds compared to their untreated counterparts.
The study appears in PLoS ONE.