By People Staff
August 14, 1995 12:00 PM

SOMEDAY ROSEANNE WILL BORROW a little black dress from Sharon Stone to wear on Oscar night, folks won’t be able to tell Siskel from Ebert, and everyone will be able to eat cheesecake all day and still look like a Calvin Klein model. Fat chance? Maybe not.

Now that researchers at Howard Hughes Medical Institute and Rockefeller University in New York City have identified a gene that regulates body weight, Americans can begin to hope that love handles and cellulite may go the way of the whalebone corset. From the gene the scientists have developed a protein hormone named leptin, whose absence in genetically defective mice causes obesity. Injecting the lab animals with the protein made even the flabbiest mice shed up to 40 percent of their body weight within a month. “They were in a cage where they had all the food they wanted,” says Dr. Jeffrey Friedman, a molecular geneticist who led the team. “They just chose to eat less.”

The researchers gave daily doses of leptin to the obese mice—with spectacular results. “After the first day, the fat went down,” says Friedman. “After two days the weight loss was obvious—and it continued.” The rotund rodents shrank from as much as 2½ ounces to 1½, and even normal-weight mice posted a quick 12 percent weight loss. Leptin not only curbed appetites, it helped speed up metabolisms to better burn calories.

Testing on humans (who have been volunteering in large numbers) is expected to begin next year. FDA approval for general use could come in five years. But don’t toss your easy-fit jeans just yet. “Even if this works, people should not be eating high-fat diets to excess—period,” says Friedman, 41, a rangy six-footer who keeps trim by biking and playing tennis and, save for the odd cheeseburger, avoiding junk food. But he does stand to make a killing if his potential fat buster can eventually be made into a miracle cure. After a frenzied bidding war among drug manufacturers, Amgen Corp. paid $20 million to Rockefeller University and the Hughes Institute to develop a product based on Friedman’s research—which should put him in Fat City.