Scientists have known that obesity is strongly linked to diabetes, but did not understand how the extra pounds interfere with sugar metabolism. Now, University of Pennsylvania researchers have discovered a hormone, called resistin, that is released by fat cells and that interferes with the activity of insulin, producing type 2 diabetes.

"This is an extraordinarily important paper with potentially major clinical implications for people with obesity and type 2 diabetes," said Dr. Allen Spiegel, director of the National Institute of Diabetes and Digestive and Kidney Diseases. In one study, he added, the team has discovered a novel hormone secreted by fat cells, explained how the newest family of anti-diabetes drugs works and provided a key link between obesity and diabetes.

If the observations in mice are replicated in humans, [Mitchell A. Lazar] said, "measuring resistin levels could help diagnose people at risk for type 2 diabetes. If resistin is really causing insulin resistance, then lowering levels of the hormone or blocking its action could constitute a new treatment."