Overeating may cause more eating by cutting off fullness signal
In the journal Nutrition & Diabetes, researchers at Thomas Jefferson University, Philadelphia, PA, describe how they came to this conclusion after observing mice on high-calorie diets.
In previous research on colon cancer using non-obese mice, the team had come across a hormone called uroguanylin that is produced in the small intestine and then travels to the brain where it signals fullness.
Building on their earlier work, senior author and professor Scott A. Waldman, chair of pharmacology and experimental therapeutics, and colleagues decided to explore how uroguanylin might be involved in promotingobesity.
They put mice on high-calorie, obesity-inducing diets for 14 weeks and monitored what happened to uroguanylin in their guts and brains.
The researchers found that the small intestines of the overfed mice stopped producing uroguanylin. Prof. Waldman notes:
"What's interesting is that it didn't matter whether the mice were lean and overfed, or obese and overfed - uroguanylin production stopped in both groups of animals when they got too many calories."
When they examined the animals' brains, the team found the receptors for the hormone were intact - and had even increased in number - showing it was lack of production rather than poor reception that had stopped the fullness signal reaching the brain.
Stressed endoplasmic reticulum might play a role
When the overfed mice were then put on a low-calorie diet, their small intestines began producing the hormone again.
Autor / Fonte:MNT