Endothelial dysfunction is associated with a reduction in nitric oxide (NO) bioavailability. Positive effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) on the improvement of endothelial dysfunction have been shown. We investigated the effects of rosuvastatin and isoprenoid metabolites on endothelial NO synthase (eNOS) mRNA and protein expression in human umbilical venous endothelial cells after exposure to 10(-8)-10(-5) mol/l rosuvastatin for 8 and 12 h. Cell viability was not significantly altered after exposure to the statin for 12 h. In a concentration-dependent manner, rosuvastatin upregulated eNOS mRNA and protein expression. The effects on eNOS expression mediated through rosuvastatin could be reversed by treatment with mevalonate indicating inhibition of HMG-CoA reductase as the underlying mechanism. Treatment with geranylgeranylpyrophosphate, but not farnesylpyrophosphate, reversed the increase of eNOS expression induced by rosuvastatin. Rosuvastatin may have beneficial effects on endothelial dysfunction associated with cardiovascular diseases beyond its effects on lowering cholesterol. (c) 2005 Elsevier Inc. All rights reserved.