UP-REGULATION OF NITRIC-OXIDE SYNTHASE BY ESTRADIOL IN HUMAN AORTIC ENDOTHELIAL-CELLS

We have examined the effects of sex hormones on calcium-dependent NO p roduction and protein levels of NO synthase in cultured human aortic e ndothelial cells, which were treated with various doses of 17 beta-est radiol and testosterone for 8-48 h. Treatment with 17 beta-estradiol e nhanced calcium-dependent NO production, but testosterone had exerted no effect. Western blot using monoclonal anti-human endothelial NO syn thase antibody clarified that increased NO production by 17 beta-estra diol treatment,vas accompanied by increased NO synthase protein. Our r esults provide evidence that human endothelial NO synthase can be regu lated by estrogens.