New science to cut obesity levels
world could cut mounting obesity levels, charting a map of how the
'fat' hormone leptin travels through the body.
Ten years after influential obesity researcher Jeffrey Friedman and colleagues discovered leptin, researchers at Brown Medical School, Rhode Island Hospital, Harvard Medical School and Beth Israel Deaconess Medical Center have found that leptin triggers production of the active form of a peptide - alpha-MSH - in the hypothalamus, the small area in the base of the brain that controls hunger and metabolism.
They say this peptide, or small protein, is one of the body's most powerful metabolism booster signals, sending a fast, strong message to the brain to burn calories.
These latest findings could lead to new tools in the fight against the growing global tide of obesity. According to the World Health Organisation, approximately 300 million people worldwide are believed to be obese and 750 million overweight. Evidence suggests that obesity significantly increases the risk of heart disease, diabetes and other life-threatening conditions.
According to the scientists, the first 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.
Research results are published in the online early 26 July edition of the Proceedings of the National Academy of Sciences. The team's contribution to the understanding of leptin function - how alpha-MSH is produced and its power as a metabolic messenger - could help in the search for an obesity treatment, said Eduardo Nillni, an associate professor in the Department of Medicine at Brown Medical School and in Brown's Department of Molecular Biology, Cell Biology and Biochemistry.
The Brown/Rhode Island Hospital research team included Nillni and Ronald Stuart. Christian Bjorbaek, Li Guo and Heike Munzberg worked on the project through Harvard and the Beth Israel Deaconess Medical Center.
These latest findings build on the breakthrough obesity research reported in 1994 when Jeffrey Friedman and his colleagues discovered the fat hormone leptin that exerts its effects on the brain to cause decreased food intake and increased energy expenditure. They also showed that leptin is produced by fat tissue and secreted into the bloodstream, where it travels to the brain and other tissues, causing fat loss and decreased appetite.
According to the US Centers for Disease Control and Prevention, 61 per cent of adults are overweight or obese and 13 per cent of children and adolescents are seriously overweight. Each year about 300,000 Americans die of obesity-related causes. The CDC pitched the economic cost of obesity to the US at a staggering $117 billion (€96bn) in 2000.
