By Tim Bonfield
Enquirer staff writer

People hoping for an all-natural, breakthrough pill to control obesity may have to wait a few more years.

Scientists at the University of Cincinnati and 14 other medical centers worldwide have been unable to replicate what appeared to be promising obesity research coming out of London in 2002.

British researchers, led by Dr. Rachel Batterham, had reported that a naturally produced hormone, called PYY3-36, showed strong appetite control and weight loss in mice, with minimal complications. But according to an article published in today's edition of Nature, other scientists cannot reproduce the findings.

"Two years ago, this really seemed like a magic pill. Now we're back to the hard way," said Dr. Randy Seeley, a researcher at Obesity Research Center at the UC Genome Research Institute in Reading.

Dr. Matthias Tschoep, a German scientist who joined UC's genome institute in September, led the researchers who prepared the Nature article.

"This paper underscores the importance of negative data. At times, negative findings can be very important for scientists," Tschoep said.

While this particular hormone may be less promising than originally hoped, obesity research still zooms along. Worldwide, at least 45 other hormones, proteins and other "targets" for controlling appetite, absorbing food or fighting fat remain under study, Seeley said.

At UC - where the obesity research center has grown to more than 10 scientists and 85 support staff since it was launched in 1997 - more than a dozen targets are being evaluated, primarily in mice.

In Cincinnati, the most developed studies have focused on the melanocortin system, which scientists believe plays an important role in balancing food intake and body weight.

For example, when mice lack melanocortin, they become less able to control binge eating and can become obese. Meanwhile, too much melanocortin appears to play a role in anorexia and the body wasting that commonly occurs in end-stage cancer.

It will take at least a few more years to determine whether compounds that can affect melanocortin levels in mice will prove effective or safe enough for human testing, Seeley said.

E-mail tbonfield@enquirer.com