The dose-response relation of circumferential tension for the various groups. A: Effect of age (11 weeks and 19 weeks) on vasoconstriction. B: Effects of Rosi treatment on vasoconstriction. Lean: Zucker lean rats. ZDF: ZDF rats. Rosi: rosiglitazone treatment. 11w: 11 weeks of age. 19w: 19 weeks of age. #: ANOVA indicates significant difference (p < 0.05) of the dose-response curve between the ZDF rats at different age and lean rats. *: Statistical difference (p < 0.05) at single dose between ZDF rats at different age and lean rats.