Overview
- A Baylor-led team reported in Science Advances this week that metformin acts in the brain’s ventromedial hypothalamus to lower blood sugar by suppressing a protein called Rap1.
- Mice engineered to lack Rap1 in that brain region did not benefit from low-dose metformin, though insulin and GLP-1 agonists still reduced glucose.
- Very small amounts of metformin delivered into the brain cut blood sugar at doses thousands of times lower than standard oral amounts, showing the brain’s high sensitivity to the drug.
- Electrophysiology tests found the drug activates SF1 neurons only when Rap1 is present, linking the protein to neural control of glucose.
- Scientists say the work points to brain-targeted diabetes therapies and may relate to reported brain benefits of metformin, though human studies are still required before clinical use.