低氧对肺血管内皮细胞血管紧张素Ⅰ转化功能的影响

EFFECT OF HYPOXIA ON THE CONVERSION OF ANGIOTENSIN Ⅰ TO A Ⅱ IN PULMONARY VASCULAR ENDOTHELIAL CELLS

急、慢性低氧大鼠肺血管床内皮细胞血管紧张素Ⅰ(AⅠ)转化率显著低于对照组,同时,去内皮细胞组又显著低于急性低氧组;小牛肺内皮细胞在低氧30min后AⅠ转化为血管紧张素Ⅱ(AⅡ)的水平,显著低于常氧组,说明低氧可显著地抑制肺血管内皮细胞的 AⅠ转化功能,提示低氧可使肺血管内皮细胞AⅠ转化功能降低,其程度与缺氧的时间与程度有关。

The effect of hypoxia on intrapulmonary conversion of angiotensin Ⅰ (A Ⅰ) toangiotensin Ⅱ (A Ⅱ) was examined by using an isolated rat lung perparation perfusedat constant flow and cultured calf pulmonary artery endothelial cells. The conversionrate of A Ⅰ in endothelial cells of pulmonary vascular bed was found to be decreased inboth acute hypoxic and chronic hypoxic (CH--5000, CH--8000) rats. The conversionrate of A Ⅰ to A Ⅱ was significantly higher in acute hypoxic rat lungs than that in de-nuded endothelial cells rat lungs. There was no significant difference between chronichypoxic and denuded endothelial cells rat lungs. In cultured calf pulmonary artery en-dothelial cells (PAEC) exposed to hypoxia (3% O_2) for 30 minutes the conversion ofA Ⅰ to A Ⅱ was significantly reduced. In the time course of hypoxic exposure the con-version of A Ⅰ to A Ⅱ in cultured calf PAEC showed significant difference between hy-poxia and normoxia. The results indicated that (1) Acute and chronic hypoxia im-paired pulmonary conversion of A Ⅰ to A Ⅱ. (2) Effect of hypoxia on the pulmonaryconversion of A Ⅰ to A Ⅱ is associated with the degree and the time of hypoxia.