2,2',4,4',5,5'- and 3,3',4,4',5,5'-Hexachlorobiphenyl Pretreatments Alter the Biliary Excretion of a Challenge Dose of 7,12-[3H]Dimethylbenz[a]Anthracene in Rainbow Trout (Oncorhyncus mykiss)

Document Type

Article

Publication Date

1-1-1999

Description

This study compared disposition of a polycyclic aromatic hydrocarbon (PAH) in rainbow trout after di-ortho and non-ortho polychlorinated biphenyl (PCH) pretreatments. Four weeks after intraperitoneal (i.p.) injection with 50 or 250 μg of the di-ortho 2,2',4,4',5,5'-hexachlorobiphenyl (2HxCB)·g-1 or 5 or 25 μg of the non-ortho 3,3',4,4',5,5'-hexachlorobiphenyl (3HxCB)·g-1, rainbow trout were i.p. injected with 10 nmol [3H]7,12-dimethylbenz[a]anthracene (DMBA)·g-1. Livers and gallbladders were removed 16 h later. Biliary excretion of [3H]DMBA decreased after i.p. injection of 2HxCB or 3HxCB. In a second experiment, rainbow trout were fed 60 or 220 ng 2HxCB·g fish-1·day-1 or 1.9 or 7.8 ng 3HxCB·g fish-1·day-1 for 4, 8, or 12 weeks. Fish were then i.p. injected with 10 nmol [3H]DMBA·g fish-1. Liver, bile, mesenteric fat, stomach, muscle, kidney, and plasma were sampled 16 h later. Fish fed 220 ng 2HxCB·g fish-1·day-1 for 4 weeks and 60 or 220 ng 2HxCB·g fish-1·day-1 for 8 weeks had greater biliary concentrations of [3H]DMBA than controls. Biliary [3H]DMBA increased for fish fed 7.8 ng 3HxCB·g fish-1·day-1 for 4 weeks. Thus, feeding both di-ortho and non-ortho PCBs transiently stimulated [3H]DMBA biliary excretion. Growth and survival data indicated no overt toxicity of the PCB doses used here via either exposure route. High i.p. doses that inhibited biliary excretion of [3H]DMBA were probably less environmentally relevant than the dietary doses fed here.

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