A predisposition for obesity might be wired into the brain from the start, suggests a new study of rats in the February issue of Cell Metabolism, a publication of Cell Press.
Rats selectively bred to be prone to obesity show abnormalities in a part of the brain critical for appetite control, the researchers found. Specifically, the researchers show that the obese rats harbor defects in neurons of the arcuate nucleus (ARH) of the hypothalamus, which leaves their brains less responsive to the hunger-suppressing hormone leptin.
“The neurodevelopmental differences in these animals can be seen as early as the first week,” said Sebastien Bouret of the University of Southern California. “The results show that obesity can be wired into the brain from early life. The three-million-dollar question now is how to get around this problem.”
It is increasingly accepted that obesity results from a combination of genetic and environmental factors, the researchers said. Rodent models of obesity can provide valuable insights into the biological processes underlying the development of obesity in humans. The “diet-induced obese” (DIO) rats used in the current study are particularly suited to the task, according to Bouret, because their tendency to become overweight shares several features with human obesity, including the contribution of many genes.