DRD2 and Hyperglycemia: Hyperglycemia induced by quinpirole (10 μg, i.c.v.)and by l-sulpiride (10 μg, i.c.v.)was not observed in dopamine D2 receptor knockout mice (Fig. 2; quinpirole, treatment: F(3,115) = 24.64, P < 0.001, treatment × time: F(15,115) = 4.91, P < 0.001; l-sulpiride, treatment: F(3,125) = 6.29, P = 0.003, treatment × time: F(15,125) = 3.00, P < 0.001).