A new study has found that overeating reduces levels of a hormone that signals the feeling of fullness in the brain, potentially promoting more eating. The study was conducted by researchers at The Thomas Jefferson University. They found that a hormone called uroguanylin also appeared to play a role in obesity. The study published in the journal Nutrition & Diabetes.
During their research, they found that in non-obese mice, uroguanylin would travel to the brain, where it produced a feeling of fullness. But it was unclear what happened to this signalling in the obese state. Now, the researchers looked at mice who were overfed, and saw that the small intestines of these mice had stopped producing uroguanylin.
The study also showed that the receptors for uroguanylin that reside in the brain were intact, and had even increased in number, but hormone itself was no longer being made, suggesting that overeating had caused its production to shut down. But, when the animals were put on a diet, the guanylin production resumed.
Say the researchers, What`s interesting is that it didn`t matter whether the mice were lean and overfed, or obese and overfed - urogaunylin production stopped in both groups of animals when they got too many calories. Taken together, these experiments show that excess calories - either from fat or carbohydrates - stress small intestinal cells so that they stop producing uroguanylin, which helps people feel full after eating. What we don`t know is how much is too much and what molecular sensor makes that decision.