Scientists at the European Molecular Biology Laboratory (EMBL), the German Institute for Nutrition and the University of Cincinnati in the US have identified the molecule that dictates why some of us gain weight more easily than others. The research was carried out as part of the DIABESITY project, funded under the EU's Sixth Framework Programme. Why does the same diet lead to some of us gaining more weight than others? The molecule 'Bsx' provides at least part of the answer, according to the team, led by Mathias Treier. The molecule provides the link between spontaneous physical activity, such as fidgeting whilst working at a computer, and food intake. Dr Treier explains the implications of the missing Bsx molecule: 'Mice that lack Bsx in their hypothalamus are a lot lazier than normal mice. They show less spontaneous activity and less food seeking behaviour, which is based on locomotor activity.' Bsx works by regulating the expression of NPY and AgRP, which are hormones of the hypothalamus (linking the nervous system to the endocrine system) that promote feeding. So when Bsx is missing, mice will only very rarely go looking for food, even if they have been starved for an extended period. This suggests that Bsx is needed for the brain to sense and respond to hunger signals from the body. 'Bsx is conserved across species and very likely plays a similar role in controlling body weight in humans,' says Maria Sakkou, one of the research team. 'Differences in Bsx activity between individuals could help explaining why some people are intrinsically more active than others and less susceptible to diet-induced obesity. Bsx might be the key to why the same diet makes one person fat, while leaving another unaffected.' The scientists believe that the Bsx molecule could be used to control diet-induced obesity in humans. The research was published in the June 2007 issue of Cell Metabolism.
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