MECHANISMS OF BILE PIGMENT EXCRETION

胆色素排泄机制

• 批准号: 3483692
• 负责人: IRWIN Monroe ARIAS
• 金额: $ 55.23万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-12-01 至 1994-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3483692
• 关键词: anions; beta glucuronidase; bile pigments; binding proteins; biopsy; biotransformation; cell membrane; cholangiography; cholestasis; circular dichroism; congenital hemolytic anemia; contrast media; esterification; excretion; fatty acid binding protein; fatty acid transport; female; genetic disorder diagnosis; glucuronides; glucuronosyltransferase; glutathione; heme; hepatocellular carcinoma; hereditary hyperbilirubinemia; human pregnant subject; human subject; hyperbilirubinemia; immunofluorescence technique; inborn biological transport disorder; intestines; ionophores; jaundice; kidney disorder diagnosis; kidney pharmacology; laboratory rat; lipogenesis inhibitor; liver cells; liver disorder diagnosis; liver function; liver metabolism; liver pharmacology; mathematical model; molecular pathology; molecular site; peptide structure; porphyrin metabolism; pregnancy disorder; protein isoforms; protein structure; radioimmunoassay; renal tubular transport; secretion; transferase; transport proteins

Using cell biological, biochemical, biophysical and immunomorphological methods, we seek to continue studies of the mechanisms involved in the transfer of bilirubin and other organic anions from blood to bile. (1) The role of hepatic endothelial cell fenestrae in controlling the uptake of bilirubin and other substances will be studied based upon characterization of fenestral dynamics in culture and effects on uptake mechanisms in isolated perfused rat liver. (2) Unique peptides from different isoforms of UDP glucuronyl transferase from normal and mutant (Gunn) rats will be sequenced and used for synthesis of oligonucleotide probes to identify isoform-specific cDNAs; the long range goal is to correct defective bilirubin UDPGI activity in Gunn rats and patients with the Crigler-Najjar syndrome, Type I. (3) Study of cellular mechanisms involved in cholestasis will be performed using isolated hepatocytes and vesicles derived from the sinusoidal and canalicular domains of the plasma membrane of hepatocytes; specifically, the role of membrane lipids, fluidity, polarity and the relation between transport events in the sinusoidal domain and observed defects in canalicular structure and function. A novel hypothesis that a group of canalicular plasma membrane ecto-"ATPases" protect hepatocytes from extracellular ATP concentrations will also be tested. (4) Functional and structural studies will be performed using sinusoidal and canalicular plasma membrane vesicles from animals with autosomal recessively inherited defects in membrane transport affecting bilirubin and other organic anions. The group includes heterozygotes and homozygotes for an "uptake defect" in Southdown sheep, the Dubin-Johnson syndrome in Corriedale sheep, and newly described conjugated hyperbilirubinemia in Wistar rats and cholestasis in homozygous athymic:heterozygous Gunn rat hybrids after administration of ethinyl estradiol. The goal is to define basic transport defects in these mutants.

利用细胞生物学、生化、生物物理和免疫形态学 方法，我们试图继续研究涉及到的机制 胆红素和其他有机阴离子从血液到胆汁的转移。(1) 肝内皮细胞窗孔在控制肝摄取中的作用 胆红素和其他物质将根据特性进行研究 培养中的窗孔动态及其对吸收机制的影响 分离灌流的大鼠肝脏。(2)不同亚型的独特多肽 正常和突变(Gunn)大鼠的UDP葡萄糖醛酸基转移酶 测序并用于合成寡核苷酸探针以鉴定 异构体特异的cDNA；长期目标是纠正有缺陷的 Gunn大鼠和Crigler-Najjar患者胆红素UDPGI活性的研究 I型综合征(3)胆汁淤积的细胞机制研究 将使用分离的肝细胞和来自 肝细胞质膜的窦状区和小管状区； 具体地说，膜脂的作用、流动性、极性和 正弦波域输运事件与观测数据的关系 小管结构和功能缺陷。一个新的假设是一个 小管质膜胞外“ATPase”组对肝细胞的保护 来自细胞外的ATP浓度也将进行测试。(4)功能 结构研究将使用正弦和管状结构 常染色体隐性遗传动物的质膜囊泡 影响胆红素和其他有机物的膜转运缺陷 阴离子。这一组包括杂合子和纯合子，以进行“吸收” 南绒绵羊的“缺陷”，科里代尔绵羊的杜宾-约翰逊综合征， 和新描述的Wistar大鼠的高结合胆红素血症和 纯合子无胸腺大鼠胆汁淤积：杂合子Gunn大鼠 乙炔雌二醇的给药。目标是定义基本交通工具 这些突变体的缺陷。