Agents for preventing or ameliorating insulin resistance and /or obesity

The present invention provides a low-molecular inhibitor of GIP functions and, further, an agent for preventing/ameliorating obesity based on inhibition of GIP functions, which comprises, as an active ingredient, a compound represented by the following general formula (I): (wherein R1 represents hydrogen, halogen, a nitro group or a cyano group, R2 and R3 each represent hydrogen or halogen, hydrogen or a methoxy group, or both R2 and R3 may form an optionally substituted benzene or pyrrole ring, and A represents nitrogen or C-R4 whereupon R4 represents hydrogen, an optionally substituted C1 to C6 alkyl group, -OR7, -NR8R9, -NHCO-R1 or -SO2-R or may, together with R3, form an optionally substituted benzene or pyrrole ring, R7, R8 and R9 each represent hydrogen or an optionally substituted C1 to C6 alkyl group, R10 represents a C1 to C6 alkyl group or the like, and R1 represents an optionally substituted morpholyl group or the like) or a pharmaceutically acceptable salt thereof.