A newly discovered signaling pathway in the brain may change how we treat obesity and eating disorders by targeting cells long dismissed as mere “support” for neurons. Research published April 6, 2026, in the Proceedings of the National Academy of Sciences reveals that astrocytes—the most abundant glial cells in the brain—play an active, direct role in regulating appetite.
For decades, the scientific consensus was that neurons handled the heavy lifting of brain signaling, while astrocytes acted as secondary support structures. However, a collaborative effort between the University of Maryland and the University of Concepción in Chile has uncovered a complex communication chain in the hypothalamus, the region of the brain responsible for hunger, and satiety.
The “Middleman” in Appetite Control
The process of detecting fullness begins with specialized cells called tanycytes, which line a fluid-filled cavity in the brain. These cells monitor glucose levels in the cerebrospinal fluid after a meal. When glucose rises, tanycytes process the sugar and release lactate, a metabolic byproduct, into the surrounding tissue.

Previously, researchers believed this lactate spoke directly to the neurons that control appetite. The new findings reveal an unexpected middleman: the astrocyte. These cells possess a specific receptor called HCAR1 that detects lactate. Once activated, the astrocytes release glutamate, a chemical messenger that then signals the neurons to suppress appetite and create the sensation of fullness.
“To put it simply, we found that tanycytes ‘talk’ to astrocytes, and then astrocytes ‘talk’ to neurons,” explained Ricardo Araneda, a professor in UMD’s Department of Biology and a corresponding author of the study.
The discovery suggests that the brain’s appetite network is more interconnected than once thought. In experiments, introducing glucose into a single tanycyte triggered activity across multiple surrounding astrocytes, demonstrating how a localized signal can spread through the brain’s network.
A Dual-Action Network for Hunger and Fullness
The hypothalamus contains two opposing populations of neurons: one group that promotes hunger and another that suppresses it. The research suggests that lactate may influence both simultaneously. While it activates “fullness” neurons via astrocytes, it may also quiet “hunger” neurons through a more direct route.
This dual-action mechanism provides a more nuanced understanding of how the body signals the brain to stop eating, moving beyond a simple “on/off” switch to a coordinated cellular conversation.
Research Context: The Evolving Role of Astrocytes
This study is part of a broader scientific shift. Recent research has increasingly shown that astrocytes are active participants in cognitive functions; for example, they have been linked to the coordination of fear memories and the formation of associative memory, challenging the traditional view that they are exclusively support cells.
From Animal Models to Potential Therapy
Because tanycytes and astrocytes exist in all mammals, including humans, the researchers believe this mechanism is likely present in people. While the current study used animal models, the identification of the HCAR1 receptor provides a concrete target for future drug development.
Currently, there are no medications that specifically target this HCAR1-astrocyte pathway. However, the team believes that targeting this receptor could lead to new therapies for obesity and eating disorders. Such a treatment could potentially complement existing medications, such as Ozempic, by attacking appetite regulation from a different biological angle.
The next phase of research will focus on whether altering the HCAR1 receptor can directly influence eating behavior, a necessary step before any human clinical applications can be explored.
This discovery is the culmination of a ten-year collaboration between the laboratories of Ricardo Araneda and María de los Ángeles García-Robles, with lead experiments conducted by doctoral student Sergio López.
Understanding the Discovery
How does this differ from current obesity drugs?
Many current treatments target hormones like GLP-1 to signal fullness. This research identifies a specific cellular pathway involving astrocytes and the HCAR1 receptor in the brain, which could offer a complementary way to manage appetite.
Are these treatments available now?
No. The research is currently in the animal model stage. Further testing is required to determine if manipulating the HCAR1 receptor is safe and effective in humans.
As we uncover more about the “non-neuronal” parts of the brain, how might our approach to treating metabolic diseases shift in the coming decade?




