Backgound Essential hypertension (EH) is a polygenic inheritable disease,generally known as a combined result of genetic and environmental elements.It is possible that IR、AngiotensinⅡ(AngⅡ) and NO play important roles in the pathogenesis of EH.Methods Sixty normal subjects with a family history of EH,aged 30 to 40 years old,were recruited and randomized into two groups:30 with one parent and 30 with both parents with EH,and 30 subjects without family history of EH as controls.The plasma level of NO was determined by electrophotometer while the plasma level of fast insulin (FINS) and AngⅡ were determined by radioimmuno-assay,and insulin resistance index (IRI) was calculated.Results ① The plasma levels of FINS,AngⅡ,NO increased significantly in study groups compared with those in the control group(P < 0.01),while there were no differences in the levels of AngII,NO between the two study groups (P > 0.05).② The plasma level of AngII were positively correlated with that of NO(r=0.378,P < 0.01).Conclusions The higher levels of IR and plasma AngII and NO exist before the development of EH in normal offspring with a family history of EH,and maybe they are initial agents in the pathogenesis of EH.It indicates that the people with IR and high levels of plasma AngⅡand NO with a family history of EH are at higher risk to develop EH. Backgound Essential hypertension (EH) is a polygenic inheritable disease, generally known as a combined result of genetic and environmental elements. It is possible that IR, Angiotensin II (Ang II) and NO play important roles in the pathogenesis of EH. Methods Sixty normal subjects with a family history of EH, aged 30 to 40 years old, were recruited and randomized into two groups: 30 with one parent and 30 with both parents with EH, and 30 subjects without family history of EH as controls. plasma level of NO was determined by electrophotometer while the plasma level of fast insulin (FINS) and AngⅡ were determined by radioimmuno-assay, and insulin resistance index (IRI) was calculated. Results ① The plasma levels of FINS, AngⅡ, NO increased significantly in study groups compared with Those in the control group (P <0.01), while there were no differences in the levels of AngII, NO between the two study groups (P> 0.05) .②The plasma level of AngII were positively correlated with that of NO r = 0.378, P <0.01) .Conclusions The higher levels of IR and plasma AngII and NO exist before the development of EH in normal offspring with a family history of EH, and maybe they are initial agents in the pathogenesis of EH. that the people with IR and high levels of plasma AngⅡand NO with a family history of EH are at higher risk to develop EH.