May 3 (UPI) — People who exercise or are exposed to cold experience a boost in hormones that increase metabolism and can avoid obesity, according to a new study.
Researchers at the Joslin Diabetes Center in Boston studied how energy is burned, finding that a hormone rises in the bloodstream during exercise, as well as during cold exposure. The research examining fat-controlling hormones — called lipokines in exercise — were published this week in the journal Cell Metabolism.
In humans and mice, levels of one lipokine — called12,13-diHOME — climbed significantly during exercise, as compared to other lipokines analyzed.
“Our recent study demonstrated that both acute and chronic cold exposure increase the circulating lipokine 12,13-diHOME and that an increase in this lipid is associated with improved metabolic health,” the researchers wrote.
The researchers said this is the first comprehensive study of lipokines in exercise.
“This is a whole new area in research on exercise metabolism, and we seem to have found another mechanism by which exercise can have beneficial effects,” Dr. Laurie Goodyear, a researcher at Joslin and associate professor in medicine at Harvard Medical School, said in a press release.
“We found it very striking that when we then analyzed lipokines in exercise, the same lipokine that increased with cold also increased with exercise.”
Following up research last year at Joslin, researchers in the new study explored the release of lipokines from brown fat, which can burn energy in people or other mammals when exposed to cold.
Among 27 healthy male volunteers, they measured levels of lipokines before exercise, immediately after exercise and three hours after exercise. Then they studied 12 healthy young people — six men and six women — who did not have regular exercise routines.
Like the other group, they found lipokines generally climbed substantially during exercise.
In general, the more fit people were, the greater their resting levels of 12,13-diHOME, researchers found.
“When mice do a single bout of exercise, we see an increase in 12,13-diHOME,” Goodyear said. “We also saw an increase after exercise training.”
Investigators, in examining molecular clues near source of the lipokine, found it was because of brown fat. When they removed most brown fat from mice, they found that 12,13-diHOME levels in exercise dropped sharply.
“It seems to be the first example of a hormone released from brown fat that might regulate some of the metabolic effects of exercise,” Goodyear said. “Most of our data suggests that exercise doesn’t ramp up the energy expenditure of brown fat, but here, exercise is clearly having an effect on brown fat.”
Then when mice and mice muscle cells were given 12,13-diHOME, the lipokine acted as a signal to boost the use of fatty acids as fuels, Goodyear said.
“The more knowledge we have about exercise and how it works, the better we can understand how to combat metabolic disease,” she said.