BIOSYNTHESIS OF LIVER ALKALINE PHOSPHATASE

血清碱性磷酸酶(AP)是一项重要的血清标志物。 胆汁淤积症是一种胆汁从胆汁中正常流出的情况 肝脏受到干扰。胆汁淤积可能是由于身体原因 胆道树梗阻(肝外胆汁淤积症)，或来自 胆汁流动被阻断的机制鲜为人知 细胞或亚细胞水平(肝内胆汁淤积症)。 无论是什么类型的 胆汁淤积症，AP在肝脏和循环中的活性是一致的 增加了。因为肝脏中的AP大部分都是在 小管膜，目前还不清楚这种酶是如何进入 发行量。存在两种可能的解释：一种秘密形式的 这种酶可能是从头合成的，或者是膜锚定的AP。 可沿细胞间隙向正弦方向迁移 被磷脂酶C切割的膜，这两种 理论并不是相互排斥的。这项建议旨在 回答一些与AP合成有关的问题，并 肝脏的分泌物。具体地说，这些研究将集中于： 1.分泌型AP是否由肝脏合成。 2.AP合成增加是如何介导的。 3.AP附着于微粒体膜的过程。 将使用的技术包括组织化学染色 肝切片亲和层析、体外转录和 翻译、Northern杂交、组织培养和前体标记。 这项工作的意义在于了解了 AP合成过程与正常肝脏的关系 以及疾病缠身的州。

Serum alkaline phosphatase (AP) is an important marker of cholestasis, a condition in which the normal flow of bile from the liver is interrupted. Cholestasis may result from physical obstruction of the biliary tree (extrahepatic cholestasis), or from poorly understood mechanisms in which bile flow is interrupted at the cellular or sub-cellular level (intrahepatic cholestasis). Irrespective of the type of cholestasis, AP activity in the liver and circulation are uniformly increased. As most of the AP in the liver is found on the canalicular membrane, it is not clear how the enzyme gets into the circulation. Two possible explanations exist: a secreted form of the enzyme might be synthesized de novo, or membrane-anchored AP may migrate along the intercellular space towards the sinusoidal membrane where it is cleaved by phospholipase C. These two theories are not mutually exclusive. This proposal aims at answering some of the questions related to AP synthesis and secretion by the liver. Specifically, the studies will focus on: 1. Whether a secreted form of AP is synthesized by the liver. 2. How the increased synthesis of AP is mediated. 3. The process of AP attachment to the microsomal membrane. The techniques that will be used include histochemical staining of liver sections affinity chromatography, in vitro transcription and translation, Northern blots, tissue culture and precursor labeling. The significance of the work lies in gaining an understanding into the process of AP synthesis as it relates to the liver in normal and diseased states.