Doctors have used metformin for decades to treat type 2 diabetes, but a fundamental question remains: how exactly does it lower blood sugar levels? An international study led by Baylor College of Medicine now suggests that the answer might be found inside the brain.
Published in Science Advances, the research challenges the traditional view that metformin primarily acts in the liver and digestive system. Instead, scientists examined a protein called Rap1 located in the ventromedial hypothalamus, a part of the brain that regulates energy use and helps maintain blood sugar within normal limits. They found that metformin decreases the activity of Rap1, which in turn helps to normalize blood sugar levels.
To verify this, researchers studied diabetic mice lacking Rap1 in that specific brain region. Unlike typical mice, these animals showed little response to low doses of metformin, while other diabetes medications like insulin and GLP-1 analogs still lowered blood sugar, indicating this new pathway is unique to metformin.
The team further tested whether metformin could act directly within the brain by injecting tiny doses into diabetic mice. Remarkably, even doses far lower than oral intake significantly reduced blood sugar levels. Additional experiments revealed that metformin activates SF1 neurons in the brain — but only when Rap1 is present. Without Rap1, these neurons did not respond, confirming that the protein is crucial for this recently discovered mechanism.
This breakthrough could have significant medical implications. Developing drugs that target this brain pathway more precisely might lead to improved blood sugar control with fewer side effects. Additionally, this research could shed light on other potential benefits of metformin, such as its possible effects on brain aging.
The researchers plan to explore whether this brain pathway also underlies some of the broader health benefits linked to metformin. Better understanding of this connection could lead to new treatments for not just diabetes but other conditions involving brain health and metabolism.
For those interested in diabetes management, exploring studies on Vitamin D and its relation to type 2 diabetes, as well as which fruits are best for people with diabetes, can be helpful. Recent research also suggests that low-calorie diets might reverse diabetes, and certain vitamins could prevent complications.
Source: Baylor College of Medicine.