An interesting case with obese and ketosis-prone type 2 diabetes suggesting metformin action on the adipose tissue

We report a 63-year-old obese ketosis-prone diabetic woman who was being treated with metformin and a low dose of insulin. We performed two hyperinsulinemic-euglycemic clamp studies followed by an oral glucose load (clamp-OGL) with and without administration of metformin. These clamp studies revealed that her splanchnic glucose uptake (SGU) was increased from 27.6 to 64.4% by metformin administration, though the glucose infusion rate (GIR) was not altered. Further investigation indicated that the intrahepatic lipid (IHL) content was low in this patient. After she stopped metformin, the fasting plasma glucose, free fatty acid, and ketone body levels were elevated, while these were decreased by re-administration of the drug. Our results suggest that metformin might not only act on the liver, but also on adipose tissue, and it could be an adjunctive treatment for obese patients with ketosis-prone type 2 diabetes.