From Science Daily:
Research is finally beginning to shed light on some of the reason that extra weight is difficult to shed permanently. Now, a new study has uncovered another method by which the gut senses how much food a person eats and relays that to the brain. When the gut senses too many calories, a pathway that promotes the feeling of fullness becomes blocked. The new research was published in the journal Nutrition & Diabetes, published by Nature.
Through earlier studies on colon cancer, Thomas Jefferson University researchers led by Scott Waldman, M.D., Ph.D., Chair of the Department of Pharmacology and Experimental Therapeutics at the Sidney Kimmel Medical College and researcher at the Sidney Kimmel Cancer Center at Jefferson, noticed that a hormone called uroguanylin also appeared to play a role in obesity. Their studies had shown 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 signaling in the obese state.
In the current study, the researchers looked at mice who were overfed, and saw that the small intestines of these mice had stopped producing uroguanylin. 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. However, when the animals were put on a diet, the guanylin production resumed.
“What’s interesting,” said Dr. Waldman, “is that it didn’t matter whether the…