Study Finds Genetic Tool to Limit Obesity

Blocking a certain brain chemical can curb appetites, researchers find, giving a new clue on how to slim from grossly obese to merely chubby.

New research with mice that are genetically altered to be extremely obese shows that the weight gain is controlled, in part, by the action of a brain chemical called neuropeptide Y, or NPY, said Jay C. Erickson, a Howard Hughes Institute researcher at the University of Washington.

Erickson said that mice, and perhaps humans, with a flawed gene called OB fail to produce leptin, an appetite-control protein. Without leptin, the appetite is voracious and unending. Mice with a flawed OB gene eat without restraint and become grossly fat, sterile, diabetic and lethargic.

When NPY is genetically removed, the mice slim down, become more energetic and can even reproduce. The absence of NPY suppressed appetite, Erickson said.

“NPY is the reason for about half of the obesity caused by a lack of leptin,” said Erickson. “It is only part of the puzzle.”

Erickson and two co-authors are publishing the results of the study today in the journal Science.