wildcat2030:‘Vicious cycle’ in brain keeps obesity going
In rat brain cells, obesity blocks the production of a hormone that curbs appetite and inspires calorie burning, according to new research.
The root cause appears to be a breakdown in the protein-processing mechanism of the cells, according to the researchers, who also found that they could intervene to break that cycle by fixing the core protein-processing problem.
Before the study, scientists knew that one mechanism in which obesity perpetuates itself was by causing resistance to leptin, a hormone that signals the brain about the status of fat in the body.
But years ago, senior author Eduardo A. Nillni, professor of medicine at Brown University and a researcher at Rhode Island Hospital, observed that after meals obese rats had a dearth of another key hormone—alpha-MSH—compared to rats of normal weight.
Alpha-MSH has two jobs in parts of the hypothalamus region of the brain. One is to suppress the activity of food-seeking brain cells. The second is to signal other brain cells to produce the hormone TRH, which prompts the thyroid gland to spur calorie-burning activity in the body.