Protein found to turn up metabolism in mice

By Julie Steenhuysen

CHICAGO (Reuters) - Tricking muscle tissue to burn rather than store fat has succeeded in increasing the average life span of mice and staved off some age-related diseases, U.S. researchers said on Tuesday.

Mice bred to make too much of a protein known as uncoupling protein 1 released food energy as heat instead of storing it as fat.

"What we're uncoupling is the process of burning energy from storing energy," said Dr. Clay Semenkovich of Washington University School of Medicine in St. Louis, Missouri whose research appears in the journal Cell Metabolism.

"Normally when you metabolize food, you take the energy that comes from that food and you store it. In essence, you are coupling the energy in the food into a stored form," Semenkovich said in a telephone interview.

Mice that overproduced this uncoupling protein in their muscle tissue weighed less and had less fat tissue, even though they ate the same amount as normal mice in the study.

"They lived about three months longer on average, which translates into six or seven years in human life, which is pretty good," Semenkovich said.

The protein did not extend the maximum life span of the mice, but it did increase their average life span, perhaps because they were less prone to age-related diseases, Semenkovich said.

Mice in the study had a lower incidence of vascular disease, hypertension and lymphoma, a type of cancer.