Lewicki J A, Fallon J H, Printz M P
Brain Res. 1978 Dec 15;158(2):359-71. doi: 10.1016/0006-8993(78)90681-9.
The regional distribution of angiotensinogen, the prohormone of angiotensin I, was examined in rat brain. Quantification of brain angiotensinogen concentration was difficult because of the presence of an endogenous angiotensin I degrading (i.e. angiotensinase) activity which was active at the pH of the renin-angiotensinogen incubation. This degrading activity was unequally distributed throughout the brain, and its presence in homogenates invalidated measured levels of angiotensinogen. Only following removal of the angiotensinase activity by ammonium sulfate precipitation of the prohormone could the distribution of the prohormone be determined. Angiotensinogen was widely distributed throughout 31 brain regions; however there was an approximate 12-fold variation in concentration. Highest levels of the prohormone were found in the dorsal and ventral periventricular hypothalamus, area postrema, organum vasculosum lamina terminalis, periventricular thalamus, dorsal raphe and lateral reticular formation. Significantly lower amounts were found in the parietal cortex, cerebellum, septum and pituitaries. While the majority of regions examined exhibited similar concentrations of angiotensinogen, the demonstration of regions containing either significnatly low or high amounts of prohormone is consistent with a topographical distribution of angiotensinogen in rat brain.
在大鼠脑中检测了血管紧张素原（血管紧张素I的前体激素）的区域分布。由于存在内源性血管紧张素I降解（即血管紧张素酶）活性，该活性在肾素 - 血管紧张素原孵育的pH值下具有活性，因此难以对脑内血管紧张素原浓度进行定量。这种降解活性在整个大脑中分布不均，并且其在匀浆中的存在使所测得的血管紧张素原水平无效。只有通过对前体激素进行硫酸铵沉淀去除血管紧张素酶活性后，才能确定前体激素的分布。血管紧张素原广泛分布于31个脑区；然而，其浓度存在约12倍的差异。在前脑室旁下丘脑背侧和腹侧、最后区、终板血管器、脑室旁丘脑、中缝背核和外侧网状结构中发现前体激素水平最高。在顶叶皮质、小脑、隔区和垂体中发现的量明显较低。虽然大多数检测区域的血管紧张素原浓度相似，但含有显著低量或高量前体激素区域的证明与大鼠脑中血管紧张素原的地形分布一致。
