STP737: Enhancement of Aflatoxin B1 Hepatocarcinogenesis in Rainbow Trout (Salmo gairdneri) Embryos by Prior Exposure of Gravid Females to Dietary Aroclor 1254

    Hendricks, JD
    Associate professor, research assistant, and professor, Oregon State University, Corvallis, Ore.

    Stott, WT
    Research toxicologist, Dow Chemical Corp., Midland, Mich.

    Putnam, TP
    Associate professor, research assistant, and professor, Oregon State University, Corvallis, Ore.

    Sinnhuber, RO
    Associate professor, research assistant, and professor, Oregon State University, Corvallis, Ore.

    Pages: 12    Published: Jan 1981


    Abstract

    Gravid female rainbow trout were exposed to dietary Aroclor 1254 [polychlorinated biphenyl (PCB)] for 2 months before spawning in order to deposit PCB in the lipid of the eggs. Levels of PCB in the eggs were measured, effects of PCB on liver tumor incidence initiated by embryo exposure to aflatoxin B1 (AFB1) were noted, and hepatic mixed-function oxidase (MFO) enzyme activities were determined.

    Gas chromatography showed that PCB was present in the lipids of the eggs at significantly higher levels than the background levels present in control eggs. Liver carcinoma incidence was significantly higher in the offspring from the PCB-exposed female at both 9 months (24 out of 40 versus 15 out of 40) (P < 0.025) and 12 months (53 out of 57 versus 39 out of 59) (P < 0.001), which indicates that preinduction of the liver by PCB enhances aflatoxin-initiated carcinogenesis. Mixed-function oxidase determinations also revealed trends that suggest induction of the MFO system by PCB. The cytochrome P-450 content in the PCB fry livers was 174 percent of the control values, whereas the in vitro conversion of AFB1 to aflatoxicol (AFL) was 264 percent of that of the control. These results call attention to the possible role of PCB in enhancing carcinogenesis.

    Keywords:

    rainbow trout, aflatoxin B, 1, carcinogenesis, hepatocellular carcinomas, polychlorinated biphenyls (PCBs), mixed-function oxidase enzymes, induction, aquatic toxicology, hazard assessment


    Paper ID: STP34157S

    Committee/Subcommittee: D19.05

    DOI: 10.1520/STP34157S


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