New Study Reveals Brain Pathway Behind Metformin’s Blood Sugar Control

A new study has identified a previously unrecognised brain pathway through which Metformin regulates blood sugar, reshaping understanding of how the widely used diabetes drug works.

The findings open the door to more precise and targeted therapies for managing diabetes.

Researchers, including Makoto Fukuda from Baylor College of Medicine, explored the brain’s role in glucose regulation, given its importance in controlling whole-body metabolism.

Traditionally, scientists believed that metformin primarily reduced glucose production in the liver or acted through the gut. The latest research highlights the brain as a critical site of action.

The study, published in Science Advances, focused on Rap1, a protein in the ventromedial hypothalamus, a brain region involved in regulating appetite and glucose sensing.

Researchers found that suppressing Rap1 activity enabled metformin to significantly lower blood sugar levels.

Experiments involving genetically modified mice lacking Rap1 showed that metformin lost its effectiveness, while other treatments, such as insulin and GLP-1 agonists, continued to work. This confirmed the essential role of Rap1 in mediating the drug’s effects.

Further tests revealed that delivering metformin directly to the brain, even in extremely low doses, led to a marked reduction in blood sugar.

The researchers also identified SF1 neurons as key players, observing increased activity in these cells only when Rap1 was present.

The findings suggest that metformin operates not only in the liver and gut but also in the brain, where it functions at much lower concentrations.

This breakthrough could lead to the development of new therapies that directly target brain pathways to treat diabetes more effectively.

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