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最初在猫、大鼠及人脑中发现肾素。由于肾素不能通过血脑屏障,而且摘除肾脏后脑内仍有肾素存在,因此脑内的肾素不是来自外周,而是中枢神经系统固有的。脑肾素的活性较肾皮质的弱,但较血浆中的强。脑内除了松果体、小脑及垂体活性特别强外,其他部位的活性大致相同。脑肾素来自线粒体部分或突触小体部分。此外,在脑内还可能存在肾素样称为组蛋白酶D(Cathepsin D)的羧基蛋白酶。这种酶存在于核蛋白体中,具有类似于胃蛋白酶底物的特异性,最适pH 为3～5.5,能把血管紧张素原转变成血管紧张素Ⅰ。其生理意义不明,在脑脊液中含量非常低。脑内肾素虽与肾脏肾素有几点不同,但类似点很多。脑内肾素由于醛
Renin was first found in cats, rats, and the human brain. Since renin can not pass through the blood-brain barrier, and there is still renin in the brain after removal of the kidneys, renin in the brain is not derived from the periphery, but intrinsic to the central nervous system. The activity of brain rennin is weaker than that of the renal cortex but stronger in plasma. In addition to the pineal brain, cerebellum and pituitary particularly strong activity, other parts of the same activity. Brain renin comes from the mitochondrial or synaptosome portion. In addition, there may be a renin-like carboxy-protease called Cathepsin D in the brain. This enzyme is present in the nucleoprotein and has a specificity similar to the pepsin substrate. The optimum pH is 3 to 5.5, which converts angiotensinogen to angiotensin I. Its physiological significance is unknown, and its content in cerebrospinal fluid is very low. Although there are several differences between the renin and renal renin, but a lot of similarities. Brain renin due to aldehyde