Fredlund P, Saltman S, Catt K J
J Clin Endocrinol Metab. 1975 Apr;40(4):746-9. doi: 10.1210/jcem-40-4-746.
The biological activity of angiotensin agonists has been determined in a highly sensitive in vitro assay system, based upon aldosterone production by isolated dog adrenal cells. The responses to angiotensin II and the heptapeptide [Des-Asp-1]-angiotensin II are identical, while the [Des-Asp-1, Des-Arg-2]-hexapeptide and the [Des-Phe-8]-heptapeptide are almost completely inactive. By contrast, [Sar-1]-angiotensin II, a potent agonist upon vascular smooth muscle, is also about 10 times more active than angiotensin II in stimulating the production of aldosterone by dog adrenal cells. The increased agonist activity of [Sar-1]-angiotensin II is attributable to increased binding affinity as well as increased efficacy at the adrenal receptor site. These results also suggest that conversion to the [Des-Asp-1] heptapeptide is not an important intermediate step in the action of angiotensin II upon the zona glomerulosa.
基于分离的犬肾上腺细胞产生醛固酮的情况，在一个高度敏感的体外检测系统中测定了血管紧张素激动剂的生物活性。对血管紧张素II和七肽[去天冬氨酸-1] -血管紧张素II的反应是相同的，而[去天冬氨酸-1，去精氨酸-2] -六肽和[去苯丙氨酸-8] -七肽几乎完全无活性。相比之下，[Sar-1] -血管紧张素II是血管平滑肌上的一种强效激动剂，在刺激犬肾上腺细胞产生醛固酮方面，其活性也比血管紧张素II高约10倍。[Sar-1] -血管紧张素II激动剂活性的增加归因于结合亲和力的增加以及在肾上腺受体部位效力的增加。这些结果还表明，转化为[去天冬氨酸-1]七肽不是血管紧张素II对球状带作用的重要中间步骤。
