New Breakthrough for Obesity: Leptin Influences Brain Cells that Control Appetite

Scientists are learning a bit more about appetite, which could help stem the obesity epidemic. About 20 years after learning that the hormone, leptin, regulates metabolism, appetite and weight through brain cells called neurons, researchers have found that the hormone also acts on other types of cells to control appetite.

Leptin is a hormone that's created in fat cells and informs the brain of the metabolic state. If an animal is missing leptin, or the leptin receptor, they end up eating too much and become severely obese. Needless to say, studying leptin is a good way to learn more about obesity and hunger control.

"Up until now, the scientific community thought that leptin acts exclusively in neurons to modulate behavior and body weight," said Tamas Horvath, one of the researchers, in a news release. "This work is now changing that paradigm."

Leptin is a naturally occurring hormone and is known for its hunger-blocking effect on the hypothalamus, which is a region of the brain. Yet while leptin's effect has been found to control the brain's neuronal circuits, researchers wanted to see whether it could affect cells other than neurons.

In order to find out, the researchers selectively knocked out leptin receptors in the adult non-neuronal glial cells of mice. They then recorded the water and food intake, as well as physical activity of the mice every five days. In the end, the researchers found that the animals responded less to feeding reducing effects of leptin, but had heightened feeding responses to the hunger hormone ghrelin.

"Glial cells provide the main barrier between the periphery and the brain," said Horvath, one of the researchers, in a news release. "Thus glial cells could be targeted for drugs that treat metabolic disorders, including obesity and diabetes."

The findings are published in the journal Nature Neroscience.