Extra hepatic formation of bilirubin glucuronides in the rat

Abstract

After total hepatectomy in the rat, the presence of conjugated bilirubin in the plasma has been demonstrated using an extraction technique. This is particularly striking after loading the animals with unconjugated bilirubin. The identification of bilirubin glucuronide has been achieved using thin-layer chromatography of the azopigments formed (1) with ethyl anthranilate and (2) with p-iodoaniline. Conjugated bilirubin was also formed (to a lesser extent) when either bilateral nephrectomy or abdominal evisceration were performed in addition to hepatectomy. If all three of these procedures are combined, only minute amounts of plasma-conjugated bilirubin appear. Thin-layer chromatography of the azopigments indicated that bilirubin monoglucuronide was the main pigment produced by extra hepatic conjugation of bilirubin. In none of the animals were there more than traces of bilirubin conjugates containing conjugating groups other than glucuronic acid.