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胆红素是红细胞的代谢产物,经网状内皮系统排入血浆,与血浆蛋白,主要是白蛋白结合运转至肝脏。这胆红素是所谓“游离”胆红素,非水溶性,不能通过肾小球而排入尿中,呈现范登堡间接反应。胆红素在肝细胞内与一嗜水物质,主要的是葡萄糖醛酸,但还有硫酸等结合转变为水溶性,可以排泄入胆汁,也可通过肾小球排入尿中。胆汁中结合胆红素约80%是葡萄糖醛酸胆红素,还有20%是与硫酸或其他物质结合。这些胆红素都呈现范登堡直接反应。胆汁中葡萄糖醛酸胆红素75%是双葡萄糖醛酸型,25%是单葡萄糖醛酸型。前者主要在肝内形成,后者在肝外形成。因此,肝细胞广泛损害所致之黄疸,血中结合胆红素主要的是单葡萄糖醛酸型;在梗阻性黄疸血中结合胆红素主要的是双葡萄糖醛酸型。二者均呈范登堡直接反应。在新生儿,早产儿与某些非溶血性黄疸情况均证明有葡萄糖醛酸形成机制的障碍,主要的是葡萄糖醛酸转移酶的缺陷。因此,胆红素不能正常排泄而潴留于血中,结果与溶血性黄疸相似,血浆中未结合胆红素(游离胆红素)增多。这些关于胆红素代谢的知识有利于进一步了解与解决某些临床黄疸情况的具体问题。
Bilirubin is a metabolite of erythrocytes that is released into the plasma via the reticuloendothelial system and binds to the liver in conjunction with plasma proteins, primarily albumin. This bilirubin is the so-called “free” bilirubin, water-insoluble, can not be discharged through the glomerulus, showing Vandenberg indirect reaction. Bilirubin in hepatocytes with a water-attracting substance, the main is glucuronic acid, but also the combination of sulfuric acid into water-soluble, can be excreted into the bile, but also through the glomerular into the urine. About 80% of bilirubin bound to bilirubin is glucuronidation, and 20% is bound to sulfuric acid or other substances. These bilirubin Vanderbilt are directly reflected. Bile glucuronide 75% is glucuronidation type, 25% is glucuronic acid type. The former is mainly formed in the liver, which is formed outside the liver. Therefore, the extensive damage of liver cells caused by jaundice, blood bilirubin mainly glucuronic acid type; in obstructive jaundice blood bilirubin mainly glucuronidation. Both were Vandenberg direct response. In neonates, premature infants and some cases of non-hemolytic jaundice are evidence of glucuronic acid formation obstacles, mainly glucuronyl transferase defects. Therefore, bilirubin can not be properly excreted and retained in the blood, the results and hemolytic jaundice similar to the plasma unbound bilirubin (free bilirubin) increased. These knowledge of bilirubin metabolism is conducive to further understanding and solving specific problems of clinical jaundice.