Objective: To investigate the relationship of nitric oxide (NO), endothelin-1 (ET-1) levels and pregnancy induced hypertension (PIH).
Methods: 60 patients with PIH, 45 normal pregnant women and 15 normal non-pregnant women were studied. Plasma NO levels were determined. The stable metabolic product NO2-/NO3- of NO was letermined by Griess reaction. Plasms ET-1 levels were measured with radioimmunoassay.
Results: The NO2-/NO3- levels of the normal pregnancy group were significantly higher than those of the control group (P < 0.01), particularly in the second trimester of pregnancy. The NO2-/NO3- level of PIH was significantly lower in maternal plasma than that of the last trimester of normal pregnancy (P < 0.01) and nonpregnancy (P < 0.05), and it decreased with the disease development. In severe PIH the umbilical venous blood NO2-/NO3- level was significantly lower than that in the normal term pregnancy group (P < 0.01). The maternal plasma ET-1 level in PIH was significantly higher than that in the normal term pregnancy and control groups (P < 0.01).
Conclusion: PIH might be related to decreasing synthesis and release of NO, and increasing ET-1 production.