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三、胆汁酸的代谢与功能 Metabolism and function of bile acids （一）初级胆汁酸的生物合成 Biosynthesis of primarybile acids
概念（concept)
胆固醇在肝细胞内转化生成的胆汁酸。 Cholesterol in the liver cells generated into bile acids
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胆汁酸的肠肝循环 Enterohepatic circulation of bile acid 意义(signification)
有限的胆汁酸发挥最大的乳化作用; 并使胆汁中胆汁酸/胆固醇比例恒定,不易 形成胆固醇结石。
Limited Bile acids play maximize the role of the emulsion; Bile acid / cholesterol ratio constant, Is not easy to form cholesterol gallstone.
Bile acid synthesis by the liver cells, secreted into the bile into the intestine after most of the weight can be absorbed through the portal vein back to the cycle of the liver, liver cells from the intake, and the synthesis of new bile acid secretion with bile into the intestines -- Between the liver and intestine bile acid cycle known as the bile acid enterohepatic circulation.
结合型
牛磺胆酸 taurocholic acid
牛磺鹅脱氧胆酸 taurochenodeoxycholic acid
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（二）次级胆汁酸的生物合成 Biosynthesis second bile acid 概念（concept)：
初级胆汁酸分泌到肠道后受肠道细菌作用生成的 产物。 Primary bile acid secretion by the intestinal bacterial role in post-generated product
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游离型胆汁酸 结合型胆汁酸
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第四节 肝病的生物化学代谢紊乱
一、肝硬化的临床生物化学 Clinical biochemistry of hepatocirrhosis 概念（concept) 肝硬化是一种以肝组织弥漫性纤维化、假小叶和再生 结节形成为特征的慢性肝病。是许多肝脏疾病晚期的 共同病变。临床上有多系统受累，以肝功能减损、门 脉高压两大症侯群为主要表现，晚期常出现上消化道 出血，肝性脑病，继发感染等严重的并发症。 Cirrhosis is a pathological diagnosis.It is characterized by widespread fibrosis with nodular regeneration. Its presence implies previous or continuing hepatic cell damage. 18
胆汁酸本身的负反馈调节 Bile acid is a negative feedback regulation 甲状腺激素可促进胆汁酸合成 Thyroid hormone may promote bile acid synthesis
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四.胆汁酸的肠肝循环 Enterohepatic circulation of bile acid 概念（concept) 胆汁酸经肝细胞合成后，分泌入胆汁，进 入肠道后大部分可被重吸收，经门脉循环 回到肝脏，再由肝细胞摄取，与新合成的 胆汁酸一同分泌入胆汁，肠-肝之间的胆汁 酸循环称为胆汁酸的肠肝循环。
胆汁酸代谢及其异常 Bile acid metabolism and its abnormity
一、胆汁的组成(composition of bile) 胆汁是由肝细胞将胆汁酸、无机离子和水 分等分泌到胆小管所形成。 Bile from the liver cells to bile acids, inorganic ions such as water and released into the tube formed by bile canaliculi .
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立体构象:亲水面-疏水面
（较强的乳化剂） Reduce oil/water surface tension 降低油/水两相之间的 界面张力 Make the hydrophobic lipids in aqueous micro-emulsion into a small micelle 使疏水性的脂类在水相 中乳化成细小的微团
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bile pigment
cholesterol
inorganic salt
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二、胆汁(主要是胆汁酸)的功能
Functon of bile acid
To promote digestion and absorption of fat
促进脂肪的消化和吸收 To promote the absorption of fat-soluble vitamins 促进脂溶性维生素的吸收 Regulation of cholesterol metabolism, The maintenance of cholesterol in the bile of the state of dissolution 调节胆固醇代谢,维持胆汁中胆固醇的溶解状态
原料(precursor) ：胆固醇(cholesterol ) 部位(site) ： 肝细胞(liver) 种类(type) ： 游离型、结合型
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游离型
胆酸 cholic acid 甘氨胆酸 glycocholic acid
鹅脱氧胆酸 chenodeoxy cholic acid 甘氨鹅脱氧胆酸 glycochenodeoxycholic acid
部位(site):小肠(small intestine) 大肠(large intestine)
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12 3 7
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Байду номын сангаас
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12 3 7
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7
3
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（三）合成过程(synthesis process)
关键酶：7-α羟化酶(Hydroxylase) 调节(regulation)