The brain doesn’t just react to emergencies like low blood sugar. It also helps manage glucose levels during ordinary daily activities, new research shows.
A study published in Molecular Metabolism found that specific neurons in the hypothalamus, a brain region involved in hunger and metabolism, play a key role in regulating blood sugar during routine fasting periods, such as the first few hours of sleep.
“Most studies have shown that this region is involved in raising blood sugar during emergencies,” said lead author Alison Affinati, M.D., Ph.D., of the University of Michigan and the Caswell Diabetes Institute. “We wanted to understand whether it is also important in controlling blood sugar during day-to-day activities because that’s when diabetes develops.”
The researchers focused on neurons called VMHCckbr cells, which influence fat metabolism. In mouse studies, turning off these neurons disrupted normal glucose regulation. When active, the neurons directed the body to break down fat into glycerol, which can be converted into sugar, preventing blood sugar from dropping too low overnight.
“In the first four hours after you go to bed, these neurons ensure that you have enough glucose so that you don't become hypoglycemic overnight,” Affinati said.
The findings could help explain why people with prediabetes often show increased fat breakdown at night, possibly due to overactive neurons. Importantly, the study also suggests that blood sugar regulation is more nuanced than an on–off switch. Multiple populations of neurons appear to coordinate different mechanisms depending on whether the body is resting, fasting, eating or under stress.
The research team is now exploring how these neurons interact with other brain circuits and organs like the liver and pancreas to fine-tune blood sugar levels. A deeper understanding could inform better approaches to prevent or treat diabetes.
This research was supported by the Michigan Diabetes Research Center through the National Institutes of Health, the Department of Veterans Affairs and several foundations, including the Warren Alpert Foundation, the Endocrine Fellows Foundation and the Marilyn H. Vincent Foundation, with additional support from Novo Nordisk and other partners.