ABSTRACT
To determine the vasodilator activity of 17 beta-estradiol as being genomic or non-genomic. The experimental protocol was divided into three groups, In group I aorta of rat was subjected to serial dilutions of norepinephrine and a standard concentration was selected, which produced optimal vasoconstriction. In group II, tissue was challenged with serial dilutions of 17 beta-estradiol in the presence of vascconstriction induced by the standard concentration of norepinephrine. Meanwhile in group III tissue was challenged with serial dilutions of 17 beta-estradiol in presence of standard concentration of norepinephrine after pretreatment with dactinomycin, which was used to inhibit protein synthesis so that genomic mode of action could be blocked. In our study 17 beta-estradiol, after pretreatment with dactinomycin, produced vasodilator activity in the same pattern as obtained without administration of protein synthesis inhibitor in the tissue preconstricted with norepinephrine [P<0.001]. The observations demonstrate the vasodilator activity of the 17 beta-stradiol to be its non-genomic action