Doctors know that the diabetes drug metformin needs to interact with insulin in order to be effective, but until now, researchers haven’t been able to explain how and why this interaction happens.
Scientists at McMaster University recently discovered that metformin works by reducing fat in the liver, which ultimately helps to lower blood glucose levels. The new research is published in the journal Nature Medicine.
Reducing fat in the liver
Greg Steinberg, associate professor in the Department of Medicine of the Michael G. DeGroote School of Medicine, explained that most people taking metformin have a fatty liver, which is often caused by obesity.
“Fat is likely a key trigger for pre-diabetes, causing blood sugar to start going up because insulin can’t work as efficiently to stop sugar coming from the liver,” Steinberg said.
Analyzing the effects of metformin on mice, Steinberg and his team found that the drug failed to lower the rodents’ blood sugar levels, indicating that the drug doesn’t work to directly reduce sugar metabolism, but that it acts on the liver.
“[Metformin] works on reducing harmful fat molecules in the liver, which then allows insulin to work better and lower blood sugar levels,” said Steinberg.
In trying to discover what causes fatty liver, the team found that mice with mutations of specific proteins called acetyl-CoA carboxylase (ACC) developed signs of fatty liver and pre-diabetes.
The findings could have significant implications for people who haven’t had success with metformin.
“This discovery offers a huge head start in finding combination therapies (and more personalized approaches) for diabetics for whom metformin isn’t enough to restore their blood sugar to normal levels,” said Steinberg.
Source: McMaster University