For decades, physicians and scientists have thought that metformin, a biguanide drug that is prescribed for millions of people worldwide for type 2 diabetes (T2D), mainly targets the liver to suppress glucose production. A Northwestern University-led study in mice has now found that this “wonder drug” instead acts primarily on the gut, and prevents glucose levels from rising in the blood by driving glucose utilization inside cells lining the intestine. The research found that metformin slows mitochondrial energy production in gut cells by inhibiting mitochondrial complex I in the intestinal epithelium. This then “co-opts” the intestines to function as a glucose sink, forcing the intestine to metabolize extra sugar. The study also found that another biguanide drug, phenformin, and the structurally unrelated supplement berberine, which is known as “nature’s Ozempic,” appear to engage the same pathway in the gut as does metformin. The preclinical findings could help to explain several gut-related clinical effects in people who take metformin and suggest that modulating mitochondrial metabolism in the gut may represent an effective strategy for controlling blood sugar. “Metformin essentially helps the intestine suck the glucose out of the bloodstream, which further highlights that the gut plays a major role in regulating blood sugar levels,” said corresponding author Navdeep Chandel, PhD, professor of biochemistry and molecular genetics at Northwestern University Feinberg School of Medicine. Chandel is senior and co-corresponding author of the researchers’ published paper in Nature Metabolism, titled “Metformin inhibits mitochondrial complex I in intestinal epithelium to promote glycaemic control.” Chandel is also the David W.…
