Hunger hormone gone awry?

From San Francisco, at a meeting of the Endocrine Society

People with Prader-Willi syndrome, a genetic disorder that causes constant hunger and severe obesity, have unusually high concentrations of a hormone called ghrelin, which has been linked to hunger pangs.

“These patients have higher ghrelin levels than recorded in any other humans,” says David E. Cummings of the University of Washington in Seattle. Among 18 people with Prader-Willi syndrome, blood concentrations of ghrelin were 4.5 times those in blood from people of similar weights but free of the syndrome, he says.

Ghrelin concentrations were only about 2.5 times as high in people with Prader-Willi syndrome as in healthy nonobese individuals. Cummings says that ghrelin concentrations are higher in nonobese people than in obese people. The reason, he speculates, is that the overweight body attempts to reduce appetite by producing less of the hormone.

Hunger regulation is completely awry in people with the syndrome, who tend to be slightly underweight just after birth but soon develop uncontrollable cravings for food. “They will eat anything–feces, fingers, dirt–and if untreated will die from complications of obesity before age 30,” Cummings says.

This research joins a growing body of evidence implicating ghrelin as the major biochemical cause of hunger (SN: 2/16/02, p. 107: The Hunger Hormone?; 6/8/02, p. 366: Most oil enters sea from nonaccidents). That makes the hormone a promising target for drugs designed to boost appetite among people with cancer, AIDS, and other wasting syndromes, as well as for a drug that might help people curb their appetites.