title: [Metabolism of 2,2',3,4,4',5,5'-Heptachlorobiphenyl (CB180) by Animal Liver Microsomes].
abstract: The in vitro metabolism of 2,2',3,4,4', 5,5'-heptachlorobiphenyl (CB180) was examined using liver microsomes of rats, guinea pigs and hamsters. Of liver microsomes from untreated animals, rats and guinea pigs produced one metabolite (M-1) with the activity of 1.2 and 18.1 pmol/hr/mg protein, respectively, but hamsters did not at all. Pretreatment of phenobarbital (PB) resulted in about 32-fold increase in rats, 4-fold increase in guinea pigs and an appearance of M-1 in hamsters (15 pmol/hr/mg protein). In addition, another metabolite (M-2) was formed only by liver microsomes of PB-treated guinea pigs. In contrast, pretreatment of 3-methylcholanthrene showed no metabolite in three animals. By comparison of the GC-MS data of the metabolites with synthesized authentic samples, M-1 and M-2 was determined to be 3'-hydroxy (OH)-CB180 and 4'-OH-2,2',3,4,5,5'-hexachlorobiphenyl (CB141), respectively. These results suggest that 3'-OH-CB180 is a major metabolite and is formed by PB-inducible cytochrome P450 (CYP2B enzymes) in animals and also guinea pigs possess much higher activity to metabolize CB180 than rats and hamsters.
authors.forename: Chiho
authors.initials: C
authors.lastname: Ohta
authors.forename: Koichi
authors.initials: K
authors.lastname: Haraguchi
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kato
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Endo
authors.forename: Osamu
authors.initials: O
authors.lastname: Kimura
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Koga
mesh_terms: D000818:Animals; D006224:Cricetinae; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D051381:Rats
chemical_list: C034559:2,3,4,5,3',4',5'-heptachlorobiphenyl; D011078:Polychlorinated Biphenyls