Diabetes is characterized by an increased concentration of blood sugar which damages the blood vessels and in turn, leads to various diseases. More than 400 million people worldwide suffer from diabetes, so avoiding diabetes and its related diseases is an important global medical concern. There is a range of drugs on the market which reduce the blood sugar levels on the body. Metformin is one of the oldest drug classes among them and has been used for over 60 years. Metformin, the most widely prescribed treatment for diabetes, is used as a first-line drug in many countries. Until now, Metformin’s Mode of Action and how it lowers the concentration of blood sugar had not been clear. 

Recently, A research team led by Kobe University Graduate School of Medicine’s Professor OGAWA Wataru (the Division of Diabetes and Endocrinology) and Project Associate Professor NOGAMI Munenobu (the Department of Radiology) found Metformin’s Mode of Action. They revealed that metformin, the most commonly used anti-diabetic drug, causes excretion of sugar in the stool. 

A device has recently been developed in which PET and MRI (Magnetic Resonance Imaging) are integrated (PET-MRI). A  high magnetic field MRI is used to analyze the inside of the body. It can examine body structures that CT can not analyze. The research team of Professor Ogawa used PET-MRI to investigate sugar movement in the bodies of patients with diabetes, both those who were taking metformin and those who were not. The team found that sugar (i.e. FDG) is highly concentrated in the intestines of patients taking metformin. More sugar was concentrated in patients taking metformin in the areas within the intestine that are distal to the ileum (the anal side of the small intestine) 

Taking advantage of the modern bio-imaging technology PET-MRI, the research team has confirmed that metformin facilitates blood sugar excretion from the large intestine into the stool. This is a totally new discovery never predicted before. The current discovery could clarify the Metformin’s Mode of Action, which is biological behavior for which the underlying mechanism is unknown, and lead to the production of new diabetes drugs.