For over six decades, metformin has been the most common medication prescribed for type 2 diabetes.
Millions of individuals take it daily because it efficiently lowers blood sugar, is affordable, and has a proven safety record.
However, researchers have never fully grasped how this medication functions within the body.
A recent study from Baylor College of Medicine indicates that one of metformin’s key targets may actually be in the brain rather than solely in the liver or digestive system. The research was published in Science Advances.
Traditionally, scientists believed metformin primarily worked by decreasing sugar production in the liver.
Other studies indicated that it also acts through the intestines. Given the brain’s crucial role in managing hunger, energy expenditure, and blood sugar levels, the research team wondered whether the brain might also be involved in metformin’s effects.
The scientists focused on a brain area called the ventromedial hypothalamus, which plays a vital role in metabolic regulation. Within this region, they examined a protein called Rap1. Their experiments revealed that metformin lowers blood sugar by reducing Rap1 activity in this part of the brain.
To test their hypothesis, the researchers used mice genetically modified to lack Rap1 in this brain area. These mice were fed a high-fat diet to mimic type 2 diabetes. When given small doses of metformin, these mice no longer experienced blood sugar reductions, although insulin and GLP-1 treatments still worked. This suggests Rap1 plays a specific role in metformin’s mechanism of action.
Furthermore, the team injected tiny amounts of metformin directly into the brains of diabetic mice. Even at doses thousands of times lower than oral administration, blood sugar levels dropped significantly. This demonstrated that the brain is highly responsive to the medication.
Additionally, the researchers identified a group of nerve cells known as SF1 neurons. Metformin increased activity in these neurons only when Rap1 was present. Without Rap1, these neurons did not respond, further confirming the importance of this protein in the process.
These findings imply that the brain reacts to much smaller amounts of metformin compared to the liver or intestines.
This may explain why the drug has remained effective for so many years despite incomplete knowledge about its precise action. It also opens the possibility for developing new medications that target this brain pathway more directly in the future.
If you’re interested in diabetes research, consider reading studies suggesting that not all whole grain foods benefit those with type 2 diabetes, and that green tea could help lower the risk of death associated with the condition.
For additional health information, explore recent research linking unhealthy plant-based diets to metabolic syndrome, or findings showing that a Mediterranean diet could cut diabetes risk by around one-third.
