Effects of the HF-diets on endothelial function. Concentration-response curves for phenylephrine (A) and (B), carbachol (C and D) or sodium nitroprusside (E and F) before and after metformin addition to the incubation media of thoracic aortic rings obtained from age-matched control, EVOO and M rats (n = 9 per group). The results show the contraction of the thoracic aortic rings as a percentage of the maximal contraction induced by phenylephrine (10 -8 to 10-4 M) and the relaxation as a percentage of the effect induced by carbachol (1 × 10-8 to 1 × 10-4 M) or sodium nitroprusside (1 × 10-8 to 1 × 10-4 M). * P < 0.05 significant difference compared with the control group; & P < 0.05 significant difference compared with the control and the EVOO groups by 2-way RM ANOVA. Values are the means ± SEM.