Effect of phenobarbital sodium and 3-methylcholanthrene on metabolism in vitro and toxicity of $^{14}C$-carbofuran in rat

쥐에서 phenobarbital sodium 및 3-methylcholanthrene이 $^{14}C$-carbofuran의 독성과 in vitro 대사에 미치는 영향

In order to elucidate the effect of phenobarbital sodium(PB) and 3-methylcholanthrene(3-MC) on metabolism in vitro and toxicity of $^{14}C$-carbofuran in rat, they were administered by the chemicals, alone or in combination, and their survival ratios and metabolites were investigated. The $LD_{50}$(96 hrs) value of carbofuran to rats was 6.9 mg/kg. The toxicities of the major metabolites were in the decreasing order of 3-hydroxycarbofuran, 3-ketocarbofuran, 3-hydroxycarbofuran phenol and were much lower than that of the parent compound. When the rats were orally administered by the dose of carbofuran alone, 8.4 mg/kg, the survival ratio was 0%, whereas that was raised up to $60{\sim}80%$ with 20 mg/kg of PB or 3-MC, and 100% with 60 mg/kg of PB or 3-MC. Their metabolism in vitro occurred in the microsomal fraction. In case of carbofuran alone, the major metabolite was 3-hydroxycarbofuran. When carbofuran with PB or 3-MC, on the other hand, was treated, it was 3-ketocarbofuran. In addition, when the co-factor(NADP+G-6-P+G-6-P-DG) was added to the microsomal fraction(phase I system), and a mixture of NADPH+GSH to the 105,000g supernatant(phase II system) taken by carbofuran alone, each metabolites were produced by the maximum levels, respectively. In case of the carbofuran treatment with PB or 3-MC, the microsomal fraction of phase I system produced the maximum levels of metabolites, as in the treatment of carbofuran alone, whereas the 105,000g supernatant supplemented with the co-factor NADPH+FAD(phase II system) was brought about the maximum production of metabolites. The ratio of the formation of metabolites was 2 to 3 times higher in the combined treatment of carbofuran with PB or 3-MC than in the treatment of carbofuran alone.

Phenobarbital sodium(PB) 또는 3-methylcholanthrene(3-MC)이 살충제 carbofuran의 쥐에 대한 독성과 이의 독성경감효과를 구명하기 위하여 이들을 단독 또는 조합으로 경구투여한 후 쥐의 생존율을 조사하였고, 쥐에서 carbofuran 의 in vitro 대사에 미치는 영향을 구명하기 위하여 쥐 간의 추출액에 이들을 단독 또는 조합으로 처리한 후 대사산물을 조사하였다. 쥐에 대한 carbofuran의 $LD_{50}$(96hrs)은 6.9 mg/kg이었고, 주 대사산물의 독성은 3-hydroxycarbofuran > 3-ketocarbofuran > 3-hydroxycarbofuran phenol 순으로 높게 나타났으며, 모화합물보다는 그 독성이 매우 낮았다. 쥐의 생존율은 carbofuran 8.4 mg/kg만을 투여했을 때 0%이었으나 carbofuran과 PB 또는 3-MC 20 mg/kg을 각각 조합투여시 $60{\sim}80%$로 높아졌고, 60 mg/kg 투여시에는 100% 생존하여 PB 및 3-MC의 carbofuran에 대한 독성경감 효과가 매우 컸다. 간 추출액에서 in vitro 대사의 대부분은 microsomal fraction에서 이루어지고 있었다. Carbofuran 단독처리시 주 대사산물은 3-hydroxycarbofuran이었으나 carbofuran과 PB 또는 3-MC 조합처리시 3-ketocarbofuran이었다. 또한, 기질 및 처리별 대사산물의 생성율을 조사한 결과 microsomal fraction에 carbofuran 단독 및 PB 또는 3-MC와의 조합처리 모두 co-factor로서 NADP+G-6-P+G-6-P-DG 첨가시(phase I system) 가장 높았고, $105,000{\times}g$ 상징액에서는 carbofuran 단독처리의 경우 co-factor로서 NADPH+ GSH 첨가시(phase II system)에 그리고 PB 또는 3-MC와 조합처리의 경우 co-factor 중 NADPH+FAD 첨가시(phase II system)에 가장 높았다. 대사산물 생성율은 carbofuran 단독처리보다 carbofuran과 PB 또는 3-MC 조합처리에서 $2{\sim}3$배 높았다.