A method of screening a compound having a hypoglycemic effect (hereinafter referred to as “hypoglycemic compound”), a remedy for diabetes which contains a compound having a novel function mechanism, etc. More specifically speaking, a method of screening a hypoglycemic compound capable of binding to the β subunit of a trimeric GTP-binding protein, a remedy for diabetes comprising a hypoglycemic compound, which is characterized by being capable of binding to the β subunit of a trimeric GTP-binding protein, as the active ingredient, etc.