Shupeck M, Wolkoff A W, Scharschmidt B F, Waggoner J G, Berk P D
Am J Gastroenterol. 1978 Sep;70(3):259-64.
Radio-labeled conjugated bilirubin was purified from rat bile by affinity chromatography. Following the intravenous injection of tracer doses of this material, the initial fractional plasma disappearance rate of conjugated bilirubin-3H in the normal Sprague-Dawley rat was found to be approximately 50% faster than that for unconjugated bilirubin-3H (0.51 +/- 0.94 [SE] vs. 0.35 +/- 0.02 min.-1; P less than .001). Hepatic recovery studies in the rat indicated that, over the first four minutes after injection, disappearance of cholephilic anions from plasma is accounted for almost entirely by hepatic uptake. Hence, these studies demonstrate that hepatic uptake of conjugated bilirubin is substantially faster than that of unconjugated bilirubin. Net hepatic clearance of conjugated bilirubin in normal rats was three-fold greater than that of unconjugated bilirubin (0.94 +/- 0.16 vs. 0.30 +/- 0.03 ml./min./100 gm. body weight; P less than .001), presumably reflecting both the more rapid hepatic uptake and the ability of the former pigment to by-pass the conjugation step. Hepatic uptake of conjugated bilirubin was shown to be inhibited by unconjugated bilirubin, sulfobromophthalein and indocyanine green but not by glycocholate. These observations cannot be explained by simple diffusion and suggest that the hepatic uptake mechanism for conjugated bilirubin is the same as that for the unconjugated pigment.
通过亲和层析从大鼠胆汁中纯化放射性标记的结合胆红素。静脉注射示踪剂量的这种物质后，发现正常斯普拉格 - 道利大鼠中结合胆红素 - 3H的初始血浆分数消失率比未结合胆红素 - 3H快约50%（0.51±0.94[标准误]对0.35±0.02分钟-1；P小于0.001）。大鼠的肝脏回收研究表明，在注射后的前四分钟内，血浆中亲胆阴离子的消失几乎完全是由肝脏摄取所致。因此，这些研究表明肝脏对结合胆红素的摄取明显快于未结合胆红素。正常大鼠中结合胆红素的肝脏净清除率比未结合胆红素高三倍（0.94±0.16对0.30±0.03毫升/分钟/100克体重；P小于0.001），这可能反映了前者更快的肝脏摄取以及该色素绕过结合步骤的能力。结果表明，未结合胆红素、磺溴酞钠和吲哚菁绿可抑制肝脏对结合胆红素的摄取，但胆酸不会。这些观察结果无法用简单扩散来解释，提示肝脏对结合胆红素的摄取机制与未结合色素相同。
