Lamé M W, Jones A D, Morin D, Segall H J, Wilson D W
Department of Veterinary Molecular Biosciences, University of California, Davis 95616, USA.
Drug Metab Dispos. 1995 Mar;23(3):422-9.
The biliary excretion of amphoteric pyrroles was studied using in situ isolated rat liver preparations perfused in a recirculatory manner for 60 to 90 min with 14C-monocrotaline (40 mumol/120 ml of Krebs-Henseleit buffer). After 90 min, 20% of the administered 14C and an amount of pyrrole equivalent to 9 mumol of dehydroretronecine was recovered in the bile. Bile collected between 15 and 30 min contained the highest levels of 14C and pyrrolic metabolites. Isoelectric focusing (IEF) and electrophoretic separations on matrices of polyacrylamide and silica were used to isolate and estimate levels of pyrrolic conjugates. IEF and electrophoretic separations on silica revealed the presence of six pyrrole-positive metabolites. Reactions of monocrotaline pyrrole with glutathione produced three conjugates that had the same pI values as components found in bile. Electrophoretic separations on silica and polyacrylamide followed by reversed phase chromatography removed sufficient biliary matrix contaminants to permit identification of glutathione and cysteinyl-glycine conjugates of 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine and 1-formyl-7-hydroxy-6,7-dihydro-5H-pyrrolizine with fast atom bombardment MS/MS. This study revealed a complexity in the biliary pyrrolic excretion profile that had not previously been realized.
使用原位分离的大鼠肝脏制剂进行两性吡咯的胆汁排泄研究，该制剂以循环方式用14C-野百合碱（40 μmol/120 ml Krebs-Henseleit缓冲液）灌注60至90分钟。90分钟后，在胆汁中回收了20%的给药14C以及相当于9 μmol脱氢倒千里光裂碱的吡咯量。在15至30分钟之间收集的胆汁中14C和吡咯代谢物的含量最高。使用等电聚焦（IEF）以及在聚丙烯酰胺和硅胶基质上进行电泳分离来分离和估计吡咯结合物的水平。在硅胶上进行IEF和电泳分离显示存在六种吡咯阳性代谢物。野百合碱吡咯与谷胱甘肽的反应产生了三种结合物，其等电点值与胆汁中发现的成分相同。在硅胶和聚丙烯酰胺上进行电泳分离，然后进行反相色谱，去除了足够的胆汁基质污染物，以便通过快原子轰击串联质谱法鉴定6,7-二氢-7-羟基-1-羟甲基-5H-吡咯嗪和1-甲酰基-7-羟基-6,7-二氢-5H-吡咯嗪的谷胱甘肽和半胱氨酰甘氨酸结合物。这项研究揭示了胆汁中吡咯排泄谱的复杂性，而这一点以前并未被认识到。
