Figure 1: Effects of vitamin D on the endothelial-dependent relaxation of thoracic aorta isolated from diabetic mice. After 1 hour of incubation, the aortic rings were precontracted with norepinephrine (10−5 M), and then the rings were exposed to a cumulative concentration of ACH (10−9~10−5 M) to test the endothelial-dependent vasodilation. Results are mean ± SEM; each group; versus DM.