Hormone found to cut hunger

Washington Post

Scientists have discovered a new hormone made in the digestive tract that acts on the brain to reduce appetite, a potential lead in efforts to develop new weight-loss drugs.

"I think it's an excellent drug target," said Michael Cowley, a scientist at the Oregon National Primate Research Center in Beaverton and a co-author of a study on the finding, published in tomorrow's issue of the journal Nature.

The chemical messenger, known as peripheral hormone peptide YY or PYY, is produced by cells in the stomach, small intestine and large intestine in response to a meal. It carries a signal to appetite-regulating nerve cells in an area called the arcuate nucleus, in the hypothalamus at the base of the brain.

Some previously known gut hormones, also made by the stomach and intestines in response to food, help produce a feeling of satiety and signal the brain to end a meal. Ghrelin, another recently discovered stomach hormone, stimulates hunger and may help determine meal timing. PYY appears to have a different function: inhibiting appetite and helping to reduce calorie intake.

When 12 healthy, hungry volunteers at a London hospital were given PYY intravenously in doses that briefly raised their blood levels of the hormone to the height normally seen after meals, they reported significantly decreased hunger. Compared with a similar group who were given saline solution, they ate more than one-third less when provided with a buffet meal, and their total calorie consumption during the 24 hours following the treatment was about 33 percent lower.

Cowley said the volunteers were monitored for possible side effects of PYY, such as nausea, diarrhea or increased heart rate. "They were fine," he said. "They showed none of those effects."

Scientific teams at London's Imperial College Faculty of Medicine, Oregon Health and Sciences University in Portland and Australia's Garvan Institute of Medical Research collaborated on research.