MK-0557

A potent and selective antagonist of the neuropeptide Y (NPY) receptor Y5. It is >7,500-fold selective for Y5 over other receptors and lacks activity in a panel of 180 receptors, enzymes, and ion channels at concentrations up to 1 μM. In vivo, MK-0557 (30 mg/kg) reduces body weight gain in wild-type and diet-induced obese mice. It also reduces retroperitoneal fat pad weight, epididymal and mesenteric fat pad weights, leptin levels, and food intake in lean mice fed a high-fat diet.