27th July 2011
Brain Research Medical

Sensor for glucose in the brain regulates body weight

By Joachim Czichos
If the brain cells no longer respond to sugar levels, increases the risk for obesity
New York (USA) – Certain hormones and nutrients in the blood in the brain producing feelings of hunger and satiety. Remains fairly constant body weight. Now U.S. researchers have discovered how cells react in the brain region of the hypothalamus on blood sugar levels. A high sugar content, activated a gene that reduces appetite, so that body weight does not increase. Mice in which this gene was defective sick, easier to obesity. The previously unknown signaling pathway therefore offers the opportunity to develop new treatments against morbid obesity, the researchers write in the online journal “PLoS Biology”.The role of the protein HIF (hypoxia-induced factor) in certain brain cells was the focus of the team to Dongsheng Cai of New York’s Albert Einstein College of Medicine. The researchers investigated its role in gene regulation in the hypothalamus of mice. From other cells and tissues has been known that HIF response to a declining oxygen concentration by activating genes that adapt the metabolism to the altered conditions.The new experiments showed that HIF, known as a transcription factor, in the cells under investigation now has a second, completely different function. It is produced increased when the blood sugar level rises. Then he turns on a gene, leading to the release of a neurotransmitter (POMC), which in turn is involved in controlling energy balance and body weight.

Genetically modified mice whose HIF-production was blocked in the hypothalamus unresponsive to elevated blood sugar levels: they reduced food intake and were not obese are more likely. The researchers treated these animals through gene therapy by infiltrates an intact HIF-gene into the brain cells. That boosted the production of HIF-back and caused the mice even at high calorie diet is no longer suffering from obesity.Too low HIF-levels in the brain in humans would also be a possible cause of increasing body weight. If confirmed, the researchers said, could be the use of HIF-activating agents is a promising new therapeutic approach.