Perhaps heralding a leaner future for an ever-fatter America, scientists have gotten genetically obese mice to lose a third of their weight in two weeks by injecting them with a newly discovered hormone that regulates body fat.
Besides studying the grotesquely obese mice, the scientists, led by Jeffrey M. Friedman, a molecular geneticist at the Howard Hughes Medical Institute and the Rockefeller University, have found a nearly identical hormone in human beings.
For the Record
Los Angeles Times Friday July 28, 1995 Home Edition Part A Page 3 Metro Desk 2 inches; 42 words Type of Material: Correction
Weight-loss hormone--In Thursday's Times, a photo accompanying a story on a hormone that regulates body fat depicted a genetically obese laboratory mouse and a normal one. Though such mice were used in experiments with the hormone leptin, those in the photo had not been treated with the substance.
Moreover, while the thrust of the work involved the mouse hormone, the researchers also found that obese mice injected with the human hormone similarly lost weight. This suggests that the hormone might someday be used as a high-tech reducing drug in people.
Claiming the pioneer's right to name the discovery, Friedman proposes calling the hormone "leptin," from the Greek for "thin."
"The fact that human leptin reduces weight in the mice raises the possibility that giving leptin to people might have similar effects," Friedman said.
"Extremely exciting," said Dr. Carl Grunfeld, an endocrinologist at UC San Francisco and the Veterans Affairs Medical Center. "This is perhaps the major finding in the field of obesity in the last two decades."
"A wonderful advance," said Dr. Susan Yanovski, executive secretary of the National Task Force on the Prevention and Treatment of Obesity. "But we're a long way from knowing what's going on in human beings with obesity, or the best way to treat it."
In the recent studies, Friedman and co-workers showed that 10 obese mice injected with leptin lost an average 30% of body weight after two weeks. After 33 days, the mice had lost an average of 40%. A group of control mice, injected with saline, exhibited no such weight loss.
Stephen K. Burley, a biochemist also at Howard Hughes Medical Institute and Rockefeller University, said, "It was sort of hard to believe it when the mice started to drop weight. It was amazing."
Burley added, "The effect on these mice was like the before and after shots in those improbable body-building advertisements."
The federal government estimates that 58 million adults, or a third of the adult population, are obese, which is defined as weighing 20% or more above the ideal weight. That's a substantial jump from a decade ago, when a quarter of American adults were obese, according to the National Institute of Diabetes, Digestive and Kidney Diseases.
