ObjectiveTo study the correlation between essential hypertension and plasma aminopeptidase A.MethodsThe people of the Han nationality in Huainan city received questionnaire investigation and their blood pressure,height and weight were measured.131 individuals suffered from hypertension and 134 healthy individuals belongs to hypertensive pedigree and 127 individuals suffered from hypertension and 132 healthy individuals belongs to non-hypertensive pedigree were reseached.The level of Ang Ⅱ in plasma was detected by RIA,and the level of APA was detected by ELISA.ResultsThe levels of Ang Ⅱ and APA in plasma in HP group was significantly higher than that in NHP group in two pedigrees ( t =10.3398,6.5613,11.7089,6.6683,all P ＜ 0.01 ).Furthermore,the levels of Ang Ⅱ and APA in plasma in HP group in hypertensive pedigree was significantly higher than that in HP group in nonhypertensive pedigree(t =3.6201,6.1091,all P ＜ 0.01 ).There was significantly positive correlation between MAP and the levels of Ang Ⅱ and APA in plasma in HP group in two pedigrees ( r =0.315,0.392,all P ＜ 0.05 in non-hypertensive pedigree,and r =0.412,0.505,all P ＜ 0.01 in hypertensive pedigree ).There was positive correlation between the levels of Ang Ⅱ and APA in plasma in HP group in hypertensive pedigree ( r =0.322,P ＜ 0.05 ).ConclusionThere was significant difference between hypertensive pedigree and non-hypertensive pedigree in the levels of APA;The levels of APA in plasma in HP group was significantly increased in the individuals suffered from hypertension,and was positively correlated with MAP.