For nearly a decade, scientists have known that leptin plays an important fat-burning role in humans without understanding completely how this hormone works.

New research reported in the July 26 online early edition of the Proceedings of the National Academy of Sciences provides some new clues.

Researchers from Rhode Island and Massachusetts found that leptin triggers production of the active form of a small protein known as áMSH in the hypothalamus, the small area in the base of the brain that controls hunger and metabolism.

Researchers say áMSH is one of the body's most powerful metabolism booster signals, sending a fast, strong message to the brain to burn calories.

This message is then sent to another part of the hypothalamus, where another peptide is produced and released. This stimulates the pituitary gland, which secretes a hormone that relays the message to the thyroid, the master of metabolism. Once activated, the thyroid gland then spreads word to the body's cells to increase energy production.

Eduardo Nillni, an associate professor in the Department of Medicine at Brown Medical School said the findings of how áMSH is produced and its power as a metabolic messenger could help in the search for an obesity treatment.

"If somehow, through a drug, you can increase activity of áMSH, you'd force the body to burn more calories and lose weight," Nillni said. "That would help so many people."

Other sources: Brown University