Researchers have made a breakthrough in understanding how metformin, a widely-used medication taken by millions, actually functions. The finding could open the door to new treatments after it overturned long-held assumptions.
Metformin is a frequently prescribed drug primarily used to treat type 2 diabetes, as it assists the body in regulating insulin and reducing blood sugar levels. Until now, specialists believed the medication worked solely by targeting the liver and gut.
How Metformin Is Used
It can be used for:
- type 2 diabetes (either on its own or combined with other diabetes medicines)
- diabetes that can develop during pregnancy (gestational diabetes)
- symptoms of polyendocrine metabolic ovarian syndrome (PMOS), previously called polycystic ovary syndrome (PCOS)
- type 1 diabetes (when combined with insulin)
The NHS website says: "Type 2 diabetes is a condition where the body does not make enough insulin, or the insulin it makes does not work properly. This can cause high blood sugar (glucose) levels. Metformin works by lowering your blood sugar level."
New Discovery in the Brain
A new finding has revealed that the drug actually employs a previously undiscovered pathway in the brain to drive its anti-diabetic effects. The researchers behind the study hope this breakthrough will lead to more targeted therapies in the future by using this brain pathway, while also shedding light on some of metformin's remaining mysteries.
Science Daily reports that Dr. Makoto Fukuda, associate professor of pediatrics-nutrition at Baylor College of Medicine said: "We found that SF1 neurons are activated when metformin is introduced into the brain, suggesting they're directly involved in the drug's action."
"This discovery changes how we think about metformin. It's not just working in the liver or the gut, it's also acting in the brain. We found that while the liver and intestines need high concentrations of the drug to respond, the brain reacts to much lower levels."
Side Effects and Further Findings
The drug can have side-effects. The NHS website says: "Most side effects should ease after a couple of weeks as your body gets used to the medicine, but some can last longer. You may be more at risk of side effects if you take more than one medicine for lowering blood sugar levels, such as metformin and insulin."
The NHS says the most common side-effects are:
- tummy pain
- a change to the way things taste
- vitamin B12 deficiency, which can make you feel very tired
- feeling sick (nausea) or being sick (vomiting)
- loss of appetite
- diarrhoea
Using genetically modified diabetic mice, the scientists discovered that administering metformin directly into the brain produced a substantial impact on blood sugar levels, even when the dosage was thousands of times smaller than what would typically be consumed orally.
Scientists from the Baylor College of Medicine in America found that metformin stimulates the SF1 neuron while simultaneously 'switching off' a protein located in the ventromedial hypothalamus area of the brain. This protein, called Rap1, influences the body's glucose processing. The research revealed that metformin's blood sugar-lowering capability depended on inhibiting Rap1 activity.
