Anorectic effect of metformin in lean and genetically obese hyperglycaemic (ob/ob) mice

To investigate the effect of metformin (dimethylbiguanide) on food intake, lean and genetically obese hyperglycaemic (ob/ob) mice habituated to a restricted feeding schedule of 3.5 hr daily, received intraperitoneal (i.p.) injections of the drug 15 min before feeding. Fifty mg/kg metformin i.p. did not significantly alter food intake. However, 250 mg/kg metformin i.p. produced a transient anorectic effect in lean mice at 30-60 min, and a more rapid and more protracted anorectic effect in obese mice. Administration of metformin (50 and 250 mg/kg/day) in the drinking water for 15 days did not significantly alter daily food intake in lean and obese mice. The results indicate a mild and transient anorectic effect of a large parenteral dose of metformin in lean and obese mice.