Obesity gene identified in mice

A gene that encodes a protein called lipin seems to promote obesity in mice, even when food intake remains stable, according to researchers at the University of California, Los Angeles.

"Our findings suggest that differences in lipin levels may play a role in why some people are more prone to weight gain than others who consume the same calories," Dr. Karen Reue indicates in a UCLA press statement. The gene's effects on blood-sugar levels and insulin "may point to new therapies for diabetes," she suggests.

Dr. Jack Phan and Reue previously showed that lipin deficiency impairs fat cell development, making them more resistant to the effects of insulin.

For their current research, published in the journal Cell Metabolism, they created mice that had increased levels of lipin in muscle or fat tissue.

While on a normal diet, those with excess lipin in muscle exhibited accelerated body weight gain and elevated insulin levels, although food intake was not altered. On the same diet, sugar levels were significantly reduced while weight remained normal in mice with excess lipin in fat tissue.

When lipin was abundant in muscle, metabolism was repressed. The mice consumed less oxygen and energy expenditure was reduced.

When lipin was abundant in fat tissue, there was no difference in energy expenditure and only a trend toward slightly reduced oxygen consumption.

Lipin "may be a novel...target for the treatment of obesity," the authors write.

SOURCE: Cell Metabolism, January 2005.