Okey A B, Dubé A W, Vella L M
Cancer Res. 1984 Apr;44(4):1426-32.
Binding of the polycyclic aromatic hydrocarbon (PAH) carcinogens [3H]benzo(a)pyrene (BP) and [3H]dibenz(a,h)anthracene [DB(a,h)A] to components in rodent hepatic cytosols was characterized by sucrose density gradient centrifugation and by gel permeation chromatography on Sephacryl S-300. In hepatic cytosols from Sprague-Dawley rats, [3H]BP and [3H]DB(a,h)A bound to a component which sedimented at 8 to 9S under low-ionic-strength conditions, and had a Stokes' radius of 4.7 nm. The 8 to 9S component also bound [3H]-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and [3H]-3-methylcholanthrene (MC), two compounds previously established as Ah receptor ligands. In hepatic cytosols from C57BL/6J mice [a strain genetically "responsive" for induction of aryl hydrocarbon hydroxylase (AHH, cytochrome P1-450) by PAHs], [3H]DB(a,h)A bound to a component sedimenting at 8 to 9S which had a Stokes' radius of approximately 6 nm. The 8 to 9S component also bound [3H]TCDD and [3H]MC, but no direct binding of [3H]BP could be detected at 8 to 9S in hepatic cytosol from C57BL/6J mice, nor could specific [3H]BP binding to the 6 nm component be detected in C57BL/6J cytosol by Sephacryl S-300 chromatography. The 8 to 9S component was not detectable in hepatic cytosol from DBA/2J mice (genetically "nonresponsive" to AHH induction by PAHs) with [3H]BP or [3H]DB(a,h)A, nor with the previously established Ah receptor ligands [3H]TCDD or [3H]MC. In addition to binding to the 8 to 9S-6 nm component in C57BL/6J cytosols, [3H]BP, [3H]DB(a,h)A, and [3H]MC also bound extensively to a cytosolic component sedimenting at 4 to 5S with a Stokes' radius of approximately 3 nm. The 4 to 5S-3 nm component was present in hepatic cytosols from genetically nonresponsive DBA/2J mice, as well as in genetically responsive C57BL/6J mice. Binding of [3H]BP, [3H]DB(a,h)A, and [3H]MC to the 8 to 9S component in rodent hepatic cytosols was eliminated by incubation in the presence of a 100-fold molar excess of nonradioactive TCDD, whereas TCDD had no effect on binding of [3H]BP, [3H]DB(a,h)A, or [3H]MC to the 4 to 5S-3 nm component. The 8 to 9S component segregates with the Ahb allele in genetic crosses with mice, but the 4 to 5S component is not associated with the Ahb allele which governs AHH responsiveness. Specificity of chemicals that bind to the 8 to 9S component and segregation of the 8 to 9S component with the Ahb allele identify it as the Ah receptor which functions to regulate AHH induction in animals treated with PAHs.(ABSTRACT TRUNCATED AT 400 WORDS)
通过蔗糖密度梯度离心和Sephacryl S - 300凝胶渗透色谱法，对多环芳烃（PAH）致癌物[³H]苯并(a)芘（BP）和[³H]二苯并(a,h)蒽[DB(a,h)A]与啮齿动物肝细胞溶质中的成分结合情况进行了表征。在Sprague - Dawley大鼠的肝细胞溶质中，[³H]BP和[³H]DB(a,h)A与一种在低离子强度条件下以8至9S沉降、斯托克斯半径为4.7 nm的成分结合。该8至9S成分还结合[³H]-2,3,7,8 - 四氯二苯并 - p - 二恶英（TCDD）和[³H]-3 - 甲基胆蒽（MC），这两种化合物先前已被确定为芳烃受体配体。在C57BL/6J小鼠（一种对PAHs诱导芳烃羟化酶（AHH，细胞色素P1 - 450）具有遗传“反应性”的品系）的肝细胞溶质中，[³H]DB(a,h)A与一种以8至9S沉降、斯托克斯半径约为6 nm的成分结合。该8至9S成分也结合[³H]TCDD和[³H]MC，但在C57BL/6J小鼠的肝细胞溶质中，在8至9S处未检测到[³H]BP的直接结合，通过Sephacryl S - 300色谱法在C57BL/6J细胞溶质中也未检测到[³H]BP与6 nm成分的特异性结合。在DBA/2J小鼠（对PAHs诱导AHH具有遗传“无反应性”）的肝细胞溶质中，用[³H]BP或[³H]DB(a,h)A以及先前确定的芳烃受体配体[³H]TCDD或[³H]MC均未检测到8至9S成分。除了在C57BL/6J细胞溶质中与8至9S - 6 nm成分结合外，[³H]BP、[³H]DB(a,h)A和[³H]MC还广泛结合到一种以4至5S沉降、斯托克斯半径约为3 nm的细胞溶质成分上。4至5S - 3 nm成分存在于遗传无反应性的DBA/2J小鼠以及遗传有反应性的C57BL/6J小鼠的肝细胞溶质中。在存在100倍摩尔过量的非放射性TCDD的情况下孵育后，啮齿动物肝细胞溶质中[³H]BP、[³H]DB(a,h)A和[³H]MC与8至9S成分的结合被消除，而TCDD对[³H]BP、[³H]DB(a,h)A或[³H]MC与4至5S - 3 nm成分的结合没有影响。在与小鼠的遗传杂交中，8至9S成分与Ahb等位基因分离，但4至5S成分与控制AHH反应性的Ahb等位基因无关。与8至9S成分结合的化学物质的特异性以及8至9S成分与Ahb等位基因的分离表明它是芳烃受体，其功能是调节用PAHs处理的动物中的AHH诱导。（摘要截短至400字）
