Gut hormone could treat obesity

A hormone produced by the intestines, called peptide PYY (Y3-36), could help obese people lose weight, new research suggests. PYY has been shown to curb the appetites of normal weight individuals, but it was unclear if the hormone would also work for obese people. Leptin, a hormone that works in similar way as PYY, only seems to reduce food intake in normal weight individuals and not in obese people. Researchers from the Imperial College in London, based their studies on 12 obese and 12 lean subjects who were treated with injections of PYY or an inactive chemical. Even before giving the injections, they noted that obese subjects had lower body levels of PYY compared with lean subjects. In addition, they found that the lower the PYY level, the more obese the subject. They found that when both lean and obese subjects were offered a buffet lunch, they ate far fewer calories if they had first been given PYY rather than an inactive chemical. Moreover, PYY treatment was tied to a dramatic drop in the 24-hour calorie intake in both groups. Further testing revealed that the PYY infusion produced a fall in plasma levels of ghrelin, a well-known appetite-stimulating hormone. This is the first time that a hormone has been shown to cause a long-term reduction in calorie intake in obese volunteers. It is now need to do studies over a longer period to see whether the decrease in appetite and food intake translates into weight loss. Despite the encouraging results, it is unlikely that treatment with PYY or any single drug will induce and maintain weight loss. Successful pharmacologic treatment for obesity may be possible only by simultaneously targeting all of the body systems that are involved in obesity.