A nuclear transfer promoter for Cdc42 protein comprising an isoprenoid synthesis inhibitor and/or a geranylgeranyl transferase inhibitor such as an HMG-CoA synthase inhibitor, an HMG-CoA reductase inhibitor, an AMPK activator or a farnesyl pyrophosphoric acid synthase preparation; utilization thereof; a method therefor; a blood vessel remedy comprising the nuclear transfer promoter for Cdc42 protein as the active ingredient; and a method of screening a blood vessel remedy which comprises assaying the ability of Cdc42 protein to transfer into nucleus.