Reed R G, Davidson L K, Burrington C M, Peters T
Medical Research Institute, Mary Imogene Bassett Hospital, Cooperstown, NY 13326.
Clin Chem. 1988 Oct;34(10):1992-4.
In hepatobiliary disease and biliary obstruction, bilirubin often becomes covalently bound to albumin circulating in serum, producing a nondissociable complex. To determine how long this complexed bilirubin remains in the circulation, we compared the metabolic clearance of bilirubin-albumin complexes with the clearances of free bilirubin and unmodified albumin. Radiolabeled bilirubin, albumin, and covalent bilirubin-albumin were injected into the circulation of Sprague-Dawley rats and serial samples of plasma were analyzed for the injected compounds. The half-life of bilirubin was 6.2 min. The half-life of bilirubin covalently bound to rat serum albumin was 1.9 to 2.1 days, identical to that of unmodified rat albumin. We conclude that bilirubin covalently attached to albumin is maintained in the circulation with the long half-life of albumin rather than the short half-life of bilirubin. Because albumin in humans has a half-life of 19 days, covalent attachment of bilirubin to human albumin could result in persistence of hyperbilirubinemia long after the resolution of disease.
在肝胆疾病和胆道梗阻中，胆红素常与血清中循环的白蛋白共价结合，形成一种不可解离的复合物。为了确定这种结合胆红素在循环中存留多长时间，我们比较了胆红素 - 白蛋白复合物的代谢清除率与游离胆红素和未修饰白蛋白的清除率。将放射性标记的胆红素、白蛋白和共价胆红素 - 白蛋白注入斯普拉格 - 道利大鼠的循环系统，并对血浆系列样本中的注入化合物进行分析。胆红素的半衰期为6.2分钟。与大鼠血清白蛋白共价结合的胆红素的半衰期为1.9至2.1天，与未修饰的大鼠白蛋白相同。我们得出结论，与白蛋白共价结合的胆红素在循环中以白蛋白的长半衰期而非胆红素的短半衰期维持。由于人类白蛋白的半衰期为19天，胆红素与人类白蛋白的共价结合可能导致疾病消退后高胆红素血症仍持续存在。
