Changes In The Plasma Levels Of Some Vasoactive Substances And The Pathogenetic Significances In Descendants Of Parents With Essential Hypertension

Objective The levels of many vasoactive substances are altered in patients with essential hypertension, while the criterion of hypertension is defined arbitrarily. We tried to prove the hypothesis that there were some changes in the plasma levels of vasoactive substances in descendants of parents with essential hypertension (EH) and search its significance both for the pathogenesis of EH and for the theory of the primary prevention of EH.Methods 60 descendants, aged 26 to 40 years, of parents with essential hypertension were recruited randomly as study group which were divided into two subgroups: study group 1 with 30 descendants of one parent with hypertension and study group 2 with 30 ones of both parents with hypertension. Matched control group included 20 descendants of parents without history of hypertension. Plasma adrenomedullin (ADM) and angiotensin â…¡ (AT â…¡) were measured by radioimmunoassay. Unstable thromboxin A2 (TXA2) was judged by its intermediate thromboxin B2(TXB2). Plasma NO was determined by electrophotometer.Results 1. Plasma ADM and TXB2 were significantly higher in the study group 2 than in the study group 1 and in the control group (t=2. 22-7. 35, P<0. 01). 2. There were differences in plasma NO between the study groups and the control group(t=2. 78, P<0. 05), but there was no difference between the two study groups (t=0.18, P>0.05) . 3. The levels of AT II were elevated in both study groups in comparison with that in the control group (t=2. 22;2.27, P<0. 01:0.05) , whereas no difference was found between the plasma level of AT â…¡ in the study group 1 and the study group 2 (t=1.07, P>0. 05) . 4. There were positively correlations among concentrations of ADM, NO, AT â…¡ and TXB2 (r=0.34-0.72, P<0.05;0.01).Conclusions 1. Because of the heredity of essential hypertension, plasma levels of ADM, NO, AT â…¡or TXB2 in descendants of parents with EHhave already enhanced even though their blood pressure remains normal, which validates that there is "a prophase of essential hypertension" with abnormal levels of plasma vasoactive substances. 2. As Increased vasodilatory substances such as ADM and NO counteract vasoconstrictive substances such as Aâ…¢ and TXA2, the enhanced vasoactive substances reaches a new balance so that blood pressure can keeps in the normal range. Once the balance is.broken up, hypertension may happen. 3. The abnormal vasoactive substances such as ADM, NO, AT â…¡ or TXBa of descendants of parents with EH can serve as predictors for the development of hypertention in the future. 4. Early interference of abnormal levels of the plasma vasoactive substances might prevent the development of hypertension and atherosclerosis.