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NEW YORK (Reuters Health) - You knew that spare tire around your midsection was hard to shed, but new research suggests that it may be thwarting your diet by churning out a powerful appetite-stimulating hormone.
In a study of rats, both lean and obese, scientists found that fat cells within the abdomen produced a hormone called neuropeptide Y (NPY), an appetite stimulant that was previously thought to originate only in the brain.
Compared with their normal-weight brethren, rats that had been bred to be heavy around the middle produced substantially more NPY in their belly-fat cells, the study found.
What's more, this excess NPY stimulated the production of fat-cell precursors, which mature into full-fledged fat. The findings, published in The FASEB Journal, point to a vicious cycle by which excess belly fat propagates more belly fat.
While the study looked at rats, it's likely that the same thing is happening in overweight humans, according to lead researcher Dr. Kalping Yang, of the University of Western Ontario in Canada.
Besides leading to more fat-cell production, Yang and his colleagues say, the NPY from belly fat could also theoretically travel to the brain, where it might then trigger hunger pangs -- further hampering weight loss.
They plan to next study whether this NPY is, in fact, transported to the brain.
The findings lay the groundwork for potential new therapies in the battle of the bulge, according to Yang. It is much easier, he told Reuters Health, to target belly fat as a source of NPY than it is to target the brain.
For example, Yang explained, it might be possible to inject an NPY-inhibiting drug directly into belly fat -- or even apply it as a cream that allows enough of the drug to be absorbed through the skin.
SOURCE: The FASEB Journal, online March 7, 2008.
