DISPOSITION OF HALOGENATED DIBENZOFURANS

多氯二苯并对二恶英(PCDDs)和二苯并呋喃(PCDf)是 有毒的环境和工业污染物。皮肤吸收 构成接触这些化学品的主要途径，最大 低剂量吸收范围从40%(TCDD)到65%(TCDF)。吸收量 穿透皮肤的过程非常缓慢，但在 在接触后24至48小时内。我们对TCDD和TCDF的结果表明 物理化学性质可以控制这些物质的吸收速度 化学制品。低剂量TCDD在幼年儿童皮肤中的吸收 与成人的皮肤吸收相比，动物的吸收增加了 动物。我们的结果表明，系统性暴露的可能性 与儿童相比，成人可能会更少。 多溴二苯并对二恶英(PBDDs)和二苯并呋喃(PCDf)是 因其形成而可能造成的环境污染 某些溴化阻燃剂的热解或热解。这个 TbDD在雄性F-344大鼠灌胃给药后的处置研究 静脉注射。TBDD表现为非线性吸收动力学 口服吸收最大(约80%)的剂量为0.01umol/kg。 分布到肝脏和脂肪这两个主要组织储存库的是剂量- 依赖的，优先在肝脏而不是脂肪中蓄积 在更高的剂量。粪便是排出和排出的主要途径 是剂量依赖的。TBDD的表观终末全身半衰期为 预计为18天。在6小时内，大约6%的剂量被排出。 以代谢的形式进入胆汁；预处理似乎没有增强 胆汁排泄物。TBDD的总体处置情况似乎类似于 观察是否有TCDD。剂量依赖性的组织分布和排泄 动力学建议对高剂量到低剂量的重要考虑 推论。

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are toxic environmental and industrial contaminants. Dermal absorption constitutes a major route of exposure to these chemicals with maximal absorption of a low dose ranging from 40% (TCDD) to 65% (TCDF). Absorption through the skin occurs very slowly yet appears to be more rapid during the first 24 to 48 hours after contact. Our results with TCDD and TCDF suggest that physicochemical properties may govern the rate of absorption of these chemicals. Absorption of a low dose of TCDD through the skin of very young animals is increased compared to absorption through the skin of adult animals. Our results suggest that the potential for systemic exposure might be less in adults compared to children. Polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PCDFs) are potential environmental contaminants due to their formation from thermolysis or pyrolysis of certain brominated flame retardants. The disposition of TBDD was studied in male F-344 rats following oral or intravenous administration. TBDD exhibited non-linear absorption kinetics with maximal oral absorption (about 80%) occurring at doses <0.01 umol/kg. Distribution to the liver and adipose, the major tissue depots, was dose- dependent, with preferential accumulation in the liver versus the adipose at higher doses. Feces was the major route of elimination and excretion was dose-dependent. The apparent terminal whole body half-life of TBDD was estimated to be 18 days. Within 6 hours, about 6% of the dose was excreted into the bile in metabolized form; pretreatment did not appear to enhance biliary excretion. The overall disposition of TBDD appears similar to that observed for TCDD. The dose-dependent tissue distribution and excretion kinetics suggest important considerations for high to low dose extrapolations.