Stereospecific, high affinity binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin by hepatic cytosol. Evidence that the binding species is receptor for induction of aryl hydrocarbon hydroxylase.
Stereospecific, high affinity binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin by hepatic cytosol. Evidence that the binding species is receptor for induction of aryl hydrocarbon hydroxylase.
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DOI：
10.1016/s0021-9258(17)33205-2
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发表时间：
1976-08
期刊：
影响因子：
--
通讯作者：
A. Poland;E. Glover;A. Kende
中科院分区：
文献类型：
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作者：
A. Poland;E. Glover;A. Kende
我们之前假设芳香烃无反应性的遗传特征（多环烃小鼠的某些近交品系未能诱导芳烃羟化酶活性，以及对更有效的诱导剂 2,3,7,8-四氯二苯并-对二恶英 (TCDD) 的敏感性降低）是由于突变导致诱导受体对诱导化合物的亲和力降低。腹膜内给予 [14C]TCDD 后(6 nmol/kg)，放射性标记的肝脏累积在 C57BL/6J 小鼠中最高，在杂交 B6D2F1/J 小鼠中居中，在 DBA/2J 小鼠中最少，这一模式反映了菌株对 TCDD 羟化酶诱导的敏感性（C57BL/6J 大于 B6D2F1/J 大于 DBA/2J）。这些数据与受体突变理论相一致，表明 TCDD 的肝脏摄取已确定。 [3H]TCDD 与 C57BL/6J 小鼠肝细胞质结合的体外实验显示，[3H]TCDD 与肝细胞质的特异性结合具有 0.27 nM 的平衡解离常数和 84 fmol/mg 细胞质蛋白的高亲和力特异性结合。在 DBA/2J 小鼠的肝细胞质中观察到了 [3H]TCDD，但由于配体的水溶性有限，因此未估计 KD。23 种卤代二苯并-对-二恶英和二苯并呋喃对这种肝细胞质结合物质的结合亲和力与这些化合物作为肝芳烃羟化酶活性诱导剂的效力密切相关。诱导肝羟化酶活性的多环烃与 [3H]TCDD 竞争。与肝细胞质结合，但苯巴比妥、孕烯醇酮-16α-甲腈和类固醇激素没有特异性结合。数据表明，结合 TCDD 的肝细胞质种类是诱导肝芳烃羟化酶活性的受体，并且无反应小鼠中的突变导致受体改变，对诱导化合物的亲和力降低。
We previously hypothesized that the genetic trait of aromatic hydrocarbon nonresponsiveness (the failure in certain inbred strains of mice of polycyclic hydrocarbons to induce aryl hydrocarbon hydroxylase activity, and the diminished sensitivity to the more potent inducer 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is due to mutation which results in an induction receptor with a diminished affinity for the inducing compound. Following the intraperitoneal administration of [14C]TCDD (6 nmol/kg), hepatic accumulation of the radiolabel was greatest in C57BL/6J mice, intermediate in the hybrid B6D2F1/J mice, and least in DBA/2J mice, a pattern which mirrors the strain sensitivity to hydroxylase induction by TCDD (C57BL/6J greater than B6D2F1/J greater than DBA/2J). These data are compatible with receptor mutation theory and suggested that the hepatic uptake of TCDD is determined by the affinity of the receptor. In vitro experiments on the binding of [3H]TCDD to hepatic cytosol from C57BL/6J mice revealed a small pool of high affinity sites which stereospecifically and reversibly bind TCDD. The specific binding of [3H]TCDD to hepatic cytosol had an equilibrium dissociation constant KD of 0.27 nM and a maximum binding capacity of 84 fmol/mg of cytosol protein. Much less high affinity specific binding of [3H]TCDD was observed in hepatic cytosol from DBA/2J mice, but the KD was not estimated because of the limited aqueous solubility of the ligand. The binding affinity of 23 halogenated dibenzo-p-dioxins and dibenzofurans for this hepatic cytosol-binding species closely correlated with the potencies of these compounds as inducers of hepatic aryl hydrocarbon hydroxylase activity. The polycyclic hydrocarbons that induce hepatic hydroxylase activity competed with [3H]TCDD for hepatic cytosol binding, but phenobarbital, pregnenolone-16alpha-carbonitrile, and the steroid hormones had no specific binding. The data suggest that the hepatic cytosol species which binds TCDD is the receptor for the induction of hepatic aryl hydrocarbon hydroxylase activity, and that the mutation in nonresponsive mice results in an altered receptor with a diminished affinity for inducing compounds.