Insulin sensitivity in OP, OR, and CON rats treated with vehicle, 3 mg/kg rosiglitazone (3-ROSI), and 6 mg/kg rosiglitazone (6-ROSI). Two- way ANOVA revealed significant group (P < 0.001) and rosiglitazone treatment (P < 0.005) effects, as well as a significant group by treatment interaction (P < 0.05). *, P < 0.01 compared with OP, within treatment. †, P < 0.01 compared with vehicle, within group. Numbers in bars indicate numbers of rats.