By Carolyn Y. Johnson, Globe Staff
Boston scientists have discovered a hormone that is secreted by muscles during exercise and boosts the amount of energy the body burns, a finding that could lay the basis for new drugs for obesity, diabetes, and other diseases. A Boston startup company, Ember Therapeutics, has already licensed the technology and is working to develop a form of the hormone that could be used as a drug that would mimic some of the benefits of exercise. The new work, published online in the journal Nature, was led by Bruce Spiegelman, a cell biologist at Dana-Farber Cancer Institute and Harvard Medical School. For years, he has been unraveling questions about the formation and nature of “brown fat,” a type of fat that burns energy rather than storing it. Spiegelman and colleagues discovered that the hormone, which they named irisin, triggers changes to ordinary “white” fat that makes them resemble brown fat and increase energy expenditure. When they induced greater levels of the hormone in obese, pre-diabetic mice over a short period, they saw slight weight loss, increased energy expenediture, and improvements in insulin resistance, a risk factor for diabetes. “It’s a hormone made by muscle, put into the blood, and with exercise it increases,” Spiegelman said. “It seems to embody some of what exercise is known to do, which is have an antidiabetes, antiobesity effect.”
