When your stomach is full, how does your brain know to stop eating?

For years, scientists believed the answer centered almost entirely on neurons, the brain's primary signaling cells. But new research is challenging that idea, pointing to a more complex system involving other types of brain cells.

A study published in the >Proceedings of the National Academy of Sciences> on April 6, 2026, shows that astrocytes, which have long been considered support cells, may play a much more active role in regulating appetite than previously recognized.

Researchers from the University of Concepción in Chile, working with colleagues at the University of Maryland, uncovered a previously unknown signaling pathway in the hypothalamus, the brain region that controls hunger and fullness. The findings could eventually help scientists develop new treatments for conditions such as obesity and eating disorders.

"People tend to immediately think of neurons when they think about how the brain works," said Ricardo Araneda, a professor in UMD's Department of Biology and a corresponding author of the study. "But we're finding that astrocytes, what we used to think of as just secondary support cells, are also participating in how our brains regulate how much we eat. This research changes how we think about these communication circuits."

>How the Brain Detects Glucose After Eating>

The process begins with specialized brain cells known as tanycytes. These cells line a fluid-filled cavity deep within the brain and monitor glucose (the sugar that fuels the body) as it moves through cerebrospinal fluid.