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Headlines Published on 20 June 2007

Title Researchers find link between molecule and obesity

How does the food one person consumes make them gain weight, while there is either little or no weight change for another? This question has driven researchers over the years to find the missing piece to the puzzle. According to researchers from the European Molecular Biology Laboratory (EMBL), the Potsdam, Germany-based Institute for Nutrition (DIFE) and the University of Cincinnati, US, the answer may lie with a molecule called Bsx. The researchers discovered that Bsx links spontaneous physical activity and food intake in mice. The findings are reported in the latest issue of Cell Metabolism.

The hypothalamus, a neural structure, regulates certain metabolic processes and controls hunger and thirst.

In their study, the researchers found that when compared to normal mice, the mice without the Bsx molecule show less spontaneous physical activity, perceive hunger signals differently and have a smaller concentration of feeding hormones in their brain. Spontaneous physical activity is activity that is subconscious, or non-volitional, and includes fidgeting and shifting in a chair while at work, and the time spent moving, like walking and standing.

For these researchers, spontaneous physical activity and food intake are two key elements that regulate body weight. The hypothalamus, a basal part of the diencephalon governing the autonomic nervous system, regulates certain metabolic processes, and controls hunger and thirst, among others. It is the hypothalamus that links spontaneous physical activity and food intake.

'The molecule is called Bsx and is required for spontaneous activity,' explained Dr Mathias Treier, a researcher at EMBL. Spontaneous activity increases and makes people to find food when hunger pangs strike. 'Mice that lack Bsx in their hypothalamus are a lot lazier than normal mice,' the research team leader said. 'They show less spontaneous activity and less food-seeking behaviour, which is based on locomotor activity.' It is Bsx that connects locomotor activity with food intake in mice.

The researchers explained that the effect of Bsx emerges when expression of the hypothalamus-feeding and/or -inducing hormones NPY and AgRP is regulated. When Bsx is missing, less hormones are made. The outcome is that only rarely do the mice search for food even though they may have not eaten for days. The research team proposed that Bsx is also required to enable brain cells to sense and respond to specific hunger signals from the body; mice do not feel hunger if they don't have it.

'Bsx is conserved across species and very likely plays a similar role in controlling body weight in humans,' commented Maria Sakkou, a member of the research team. 'Differences in Bsx activity between individuals could help explain why some people are intrinsically more active than others and less susceptible to diet-induced obesity,' she said. 'Bsx might be the key to why the same diet makes one person fat, while leaving another unaffected.'

This latest development offers the research world a better understanding of how molecular mechanisms affect body weight, especially in mice, and how this may impact the treatment for obesity and related diseases, including diabetes and cardiovascular conditions.

More information:

  • EMBL
  • 'European scientists show high-protein diet fights obesity'

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