Profile Analysis of Fetal Bile Acids and Congenital Liver Diseases

(1)以胆酸为原料合成了1-β-和6-α-羟化胆汁酸和DELT、A5-不饱和胆汁酸，并从胎粪、羊水和新生儿尿液中鉴定了这些胆汁酸。通过GC-MS选择离子监测，建立了一种高灵敏、特异的胆汁酸定量分析方法。(2)在胎儿胆汁酸谱分析中，足月羊水和新生儿尿液中以1β-羟基胆酸为主，胎粪中以6α-羟基鹅脱氧胆酸为主。这些胆汁酸的含量随着妊娠的进展而增加，出生后随着发育年龄的增加而减少。牛磺酸结合物是胎粪中的主要胆盐，在新生儿胆汁中逐渐被甘氨酸结合物交换。(3)用胆汁酸分子上C-15α和C-24位偶联的半抗原-牛血清白蛋白偶联物免疫兔，制备了抗胎儿胆汁酸抗血清，并用~(125)I标记示踪剂异源结合法研究了其性质。制备的抗血清具有良好的亲和常数和较好的特异性。(4)对先天性和胆汁淤积性肝病的胎儿胆汁酸代谢进行了研究。这些结果提示，在胎儿期和胆汁淤积期，可能通过C-1β或C-6α位的羟基化和与牛磺酸的偶联作用来消除胆汁酸。

(1) The 1 beta- and 6 alpha-hydroxylated and DELT^A5-unsaturated bile acids were synthesized from cholic acid as a starting material, and these unusual bile acids were identified from meconium, amniotic fluid and neonatal urine. A highly sensitive and specific quantitative assay of these bile acids was developed by selected ion monitoring in GC-MS. The conjugated fetal bile acids were determined by HPLC using 3alpha-hydroxysteroid dehydrogenase and chemical luminesscence.(2) In profile analysis of fetal bile acids, 1 beta-hydroxylated cholic acid was predominant in full term amniotic fluid, and neonatal urine, while 6alpha-hydroxylated chenodeoxycholic acid constituted a main component in meconium. Quantity of these bile acids increased according to the progress of gestation and decreased with developmental age after birth. Taurine conjugates are main bile salts in meconium and were exchanged progressively for the glycine conjugates in neonatal biles.(3) Anti-fetal bile acid antisera were prepared by immunizing rabbits with hapten-bovine serum albumin conjugates coupled at C-15alpha and C-24 positions on the bile acid molecule, and their properties were investigated by heterologous combination assay using ^<125>I-labeled tracer. The antisera raised against these conjugates showed satisfactory affinity constants and reasonable specificity.(4) The metabolism of fetal bile acids was studied on congenital and cholestatic liver diseases. These results suggested that hydroxylation at C-1beta or C-6alpha position and conjugation with taurine in liver might be carried out for the elimination of bile acids in fetal period and cholestasis.