Here's a new paper out in Nature Neuroscience that explores the ability of the hypothalamus to sense the nutritional status of the body and modulate hunger in response.Malonyl-coenzyme A is a very interesting protein that has recently been proposed to play a central role in this pathway. Malonyl-CoA in the brian is induced by feeding and is suppressed by fasting. Here the authors treated rats with a virus encoding a protein that breaks down malonyl Co A, which resulted in rats that chronically had too little malonyl-CoA in their hypothalamus. This caused a major disruption in nutrient sensing in the hypothalamus, and led to hyperphagia and obesity in the rats. This raises the question of whether defective nutrient sensing might play a role in hyperphagia in PWS.
Molecular disruption of hypothalamic nutrient sensing induces obesity
He W, Lam TKT, Obici S & Rossetti L. Nature Neuroscience 9, 227 - 233 (2006)