Hanioka N, Saeki H K, Ishida C, Koga N, Yoshimura H
Department of Hygienic and Forensic Chemistry, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka.
Fukuoka Igaku Zasshi. 1991 May;82(5):191-6.
We observed previously that polychlorinated biphenyl (PCB) could be classified to two groups, 3-methylcholanthrene (MC)-type and phenobarbital (PB)-type, in term of inducibility of the hepatic enzymes. MC-type PCBs such as 3,4,3',4'-tetrachlorobiphenyl (TCB), 3,4,5,3',4'-pentachlorobiphenyl (PenCB) and 3,4,5,3',4',5'-hexachlorobiphenyl (HexCB) exhibited high acute toxicity in parallel with their induction ability of microsomal benzo[a]pyrene 3-hydroxylase and cytosolic DT-diaphorase. On the contrary, PB-type PCBs such as 2,5,2',5'-TCB and 2,4,5,2',4',5'-HexCB which induce microsomal benzphetamine N-demethylase and NADPH-cytochrome P-450 reductase activities showed virtually no or very low toxicity. In the present study, we examined effects of 2,5,2',5'-TCB and its major metabolite 3-hydroxy-2,5,2',5'-TCB on body weight gain, organ weights and activities of hepatic enzymes in rats and assessed acute toxicity of these compounds. As the results, in both 2,5,2',5'-TCB and 3-hydroxy-2,5,2',5'-TCB groups, the body weights were increased during the experiment, but the rate of growth was significantly suppressed after 3 days. Significant hypertrophy of the liver and decrease of total liver lipid content were observed in 2,5,2',5'-TCB group, but the atrophy of spleen and thymus was not affected in both groups. On the other hand, in 2,5,2',5'-TCB group, benzo[a]pyrene 3-hydroxylase and benzphetamine N-demethylase activities were increased to 2. 4-fold and 1.5-fold, respectively, but were not increased in 3-hydroxy-2,5,2',5'-TCB group. After injection of 2,5,2',5'-TCB, 45% of the dose was excreted as 3-hydroxy-2,5,2',5'-TCB in feces for 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)
我们之前观察到，就肝酶的诱导性而言，多氯联苯（PCB）可分为两组，即3-甲基胆蒽（MC）型和苯巴比妥（PB）型。MC型多氯联苯，如3,4,3',4'-四氯联苯（TCB）、3,4,5,3',4'-五氯联苯（PenCB）和3,4,5,3',4',5'-六氯联苯（HexCB），表现出高急性毒性，同时具有微粒体苯并[a]芘3-羟化酶和胞质DT-黄递酶的诱导能力。相反，诱导微粒体苄非他明N-脱甲基酶和NADPH-细胞色素P-450还原酶活性的PB型多氯联苯，如2,5,2',5'-TCB和2,4,5,2',4',5'-HexCB，实际上没有毒性或毒性非常低。在本研究中，我们检测了2,5,2',5'-TCB及其主要代谢产物3-羟基-2,5,2',5'-TCB对大鼠体重增加、器官重量和肝酶活性的影响，并评估了这些化合物的急性毒性。结果显示，在2,5,2',5'-TCB组和3-羟基-2,5,2',5'-TCB组中，实验期间体重均增加，但3天后生长速率显著受到抑制。在2,5,2',5'-TCB组中观察到肝脏显著肥大和肝脏总脂质含量降低，但两组中脾脏和胸腺的萎缩均未受到影响。另一方面，在2,5,2',5'-TCB组中，苯并[a]芘3-羟化酶和苄非他明N-脱甲基酶活性分别增加至2.4倍和1.5倍，但在3-羟基-2,5,2',5'-TCB组中未增加。注射2,5,2',5'-TCB后，5天内45%的剂量以3-羟基-2,5,2',5'-TCB的形式随粪便排出。（摘要截选至250词）
