''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."
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 rats eat less not because it directly suppressed their appetite but because it made them feel ill.
People should not read too much into the new hormone's name. It's not a statin like the 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. It is produced in the stomach and 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 today.
Obestatin is a sister hormone to ghrelin and is produced in the gut, too, Stanford endocrinologist Aaron Hsueh and colleagues discovered.
