HDL-associated estradiol stimulates endothelial NO synthase and vasodilation in an SR-BI–dependent manner
J. Clin. Invest. Ming Gong, et al. 111:1579 doi:10.1172/JCI16777 [Go to this article.]

Figure 2
The ability of female HDL to stimulate eNOS requires binding to SR-BI. (a) Human microvascular endothelial cells were pretreated with buffer only, 50 μg/ml of blocking SR-BI IgG, or 50 μg/ml isotype-matched nonspecific IgG for 15 minutes at 37°C. The cells were then incubated with 0.75 μCi/ml of [³H]arginine and 10 μg/ml of female HDL or 1 μg/ml of ionomycin for 15 minutes at 37°C. The cells were processed to quantify the amount of citrulline generated. Each experiment included controls, using 1 mM L-NNA to demonstrate that over 99% of the generated citrulline was due to eNOS activity (data not shown). The data are from six independent experiments, with triplicate measurements in each experiment (mean ± SE). (b) Human microvascular endothelial cells were pretreated with 0.75 μCi/ml of [³H]arginine and then incubated with 10 μg/ml of female HDL or increasing concentrations of male HDL for 15 minutes. The amount of citrulline generated was then quantified. Each experiment included controls, using 1 mM L-NNA to demonstrate that over 99% of the generated citrulline was due to eNOS activity (data not shown). The data are from six independent experiments, with triplicate measurements in each experiment (mean ± SE).