Four
Aroclor reference materials, cleaned-up extracts of 2 yusho rice oil samples, and cleaned-up extracts of 3 fish samples containing
polychlorinated biphenyl (PCB) residues were tested for their ability to induce aryl
hydrocarbon hydroxylase (AHH) activity in a rat
hepatoma cell line. Before the AHH bioassay, the samples were fractionated by a
Florisil column chromatographic method. All samples contained about 1000 micrograms
PCBs before
Florisil column chromatography. The first
Florisil eluate contains about 95% of the
PCBs in a typical
Aroclor, and the second contains the more polar or adsorbent PCB congeners. In this study, the first eluate for all samples produced no quantifiable AHH activity. The second
Florisil eluates of both
Aroclors 1242 and 1248 induced AHH activity, whereas these eluates of both
Aroclors 1254 and 1260 did not. This difference may be due to the presence in
Aroclors 1242 and 1248 of
3,3',4,4'-tetrachlorobiphenyl, which has not been detected in
Aroclors 1254 and 1260. The second
Florisil eluates of the fish samples induced somewhat less AHH activity than did
Aroclor 1242 or 1248. The second
Florisil eluates of the PCB residues from yusho rice oil samples induced significantly greater AHH activity than these eluates of either
Aroclor 1242 or 1248, perhaps because yusho rice oil contains a greater amount of
polychlorinated dibenzofurans than PCB commercial mixtures on a PCB equivalent basis.