数種淡水魚におけるp, p'-DDTの初期代謝経路の比較

Eleven freshwater fishes were kept in a flow-through aquarium system (FAS) and in a closed aquarium system (CAS) after intraperitoneal injection of p, p'-DDT (DDT). Concentrations of DDT, p, p'-DDE (DDE), p, p'-DDD and p, p'-DDT-OH in the whole body and in the CAS were determined.Japanese barbel, Japanese dace and char rapidly converted DDT into DDE only, and the ΣDDT in the whole CAS (consisted of fish, aquarium and rearing water) were nearly equal to the original DDT, suggesting only one initial metabolic pathway (IMP) changing rapidly the DDT into DDE. In crucian carp, loach, Japanese sculpin, floating goby and catfish, slight increase of only DDE were observed, and the ΣDDT in their whole CAS almost corresponded to the DDT injected, suggesting only one IMP converting slowly from DDT to DDE. The DDT in grass carp was immediately cleared and only DDE increased without delay, and the ΣDDT in the whole CAS was about 50% of the original DDT. In bluegill, only DDE gradually increased with clearance of DDT, and the ΣDDT in the whole CAS was about 85% of the original DDT. These results suggested that grass carp had IMP converting quickly from DDT to DDE and other metabolites undetermined and that bluegill had a similar pathway, but it was slower. Japanese eel might not have clear IMP, considering the fact that no metabolite was detected and the DDT injected remained completely in the whole CAS.