A group of researchers has reported discovering a mechanism through which appetite for food becomes difficult to suppress in the brain, which could lead to the development of therapies for treating obesity in the future.

The scientists with the National Institute for Basic Biology in Okazaki, Aichi Prefecture, and other institutions demonstrated that PTPRJ, an enzyme in brain cells, suppresses the workings of leptin, a hormone released by fat cells.

Appetite for food is controlled by the workings of leptin on the brain’s feeding center. It has been known that obese people have weak leptin action, which makes their appetites difficult to suppress, but how and why that occurs was previously unknown.

The team of researchers, led by Takafumi Shintani, an NIBB associate professor of neurobiology, said it has discovered that increased fat increases the amount of PTPRJ in cells, which inhibits leptin action and makes it difficult to suppress appetite.

When mice were fed for 12 weeks under identical conditions, individuals that lack PTPRJ exhibited smaller food intake and about 15 percent less body weight than normal mice. The former also had about 40 percent less total body fat, the scientists added.

Their research results were published Sept. 14 in Scientific Reports, a British science journal.