Studies: Hormone halts hunger

The hormone, obestatin, is produced in the gut.
WASHINGTON (AP) -- Scientists have discovered a biological brake for a hunger hormone: a competing hormone that seems to counter the urge to eat.
The substance, named obestatin, has been tested just in laboratory rats so far. But if it pans out, the discovery of the dueling hormones could lead not only to a new appetite suppressant, but also help unravel the complex ways that the body regulates weight.
It turns out that the same gene sparks production of the two opposing hormones, Stanford University researchers say in today's edition of the journal Science.
"It is an unexpected but very, very intriguing finding," said Matthias Tschop of the University of Cincinnati, who reviewed the work. "It seems counterintuitive that Mother Nature would press on the brake and gas pedal at the same time."
More studies
Years of additional research lie ahead to see whether obestatin might work as an appetite suppressor. Other weight-related hormones announced to great fanfare, such as leptin, have yet to lead to obesity treatments, and scientists now know that dozens of hormones probably are involved in the balancing act of weight gain and loss.
But with one-third of American adults obese and only a few prescription drugs providing modest weight-loss help, every new clue generates intense interest.
"Obese patients shouldn't get their hopes up yet," Tschop said.
Among the crucial questions to be answered is whether obestatin made the rats eat less not because it directly suppressed their appetite but because it made them feel ill.
Misleading name
People should not read too much into the new hormone's name. It's not a "statin" like that well-known class of cholesterol-lowering drugs. Instead, the name combines the Latin words for devour and suppression.
The latest discovery stems from the hunger hormone called ghrelin. Produced in the stomach, it boosts appetite. The theory is that ghrelin helped early humans survive famine by fattening them up during times when food was plentiful, a mechanism that can backfire in today's culture of plenty.
Obestatin is a sister hormone to ghrelin and is produced in the gut, too, Stanford endocrinologist Aaron Hsueh and colleagues discovered.
It might be better dubbed the anti-ghrelin.
Hsueh's team was scouring databases of genes from humans and other organisms in a quest to discover types of hormones that could be turned into drugs fairly easily. They narrowed their hunt to stretches of genes conserved through millions of years of evolution in far-ranging species, a sign that those sequences may be of particular biological importance.
Extra protein
The genetic sequence that leads to ghrelin had an extra protein hanging on the end -- obestatin. It was present in humans and at least 10 other mammal species.
The research was funded by Johnson & amp; Johnson Pharmaceutical Research & amp; Development LLC.
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