Can obesity be fought with drugs?

"There are two ways to approach the treatment of obesity, a condition that affects approximately one in three Americans," according to Robert Dow, principal research investigator with Pfizer Inc., Groton, Conn. "Either you inhibit food intake. or you improve energy expenditure to get the `exercise effect.'" Pfizer has developed compounds that, in animal trials, boosted metabolic rates to mimic the exercise effect of increased calorie burning -- without exercise. The tests showed a 10-30% jump in metabolic rate. "If you have a 10% increase in energy expenditure, you're potentially looking at about a half a pound a week drop in weight," Dow points out. There are currently no drugs on the market that work this way.

The compounds do not seem to bring about one other effect of an exercise-induced hike in metabolism. "If I go out and ski all day and I come in, I'm ravenous and I eat more," Dow says. "But that sort of compensation has not been seen in the animal tests with these compounds."

The compounds are hormone mimics that act on the beta-adrenergic system, which has three sub-types of receptors in cells in the body. These receptors are stimulated by the...