TY - JOUR
T1 - PCB isomers and congeners
T2 - Induction of aryl hydrocarbon hydroxylase and ethoxyresorufin O-deethylase enzyme activities in rat hepatoma cells
AU - Sawyer, T.
AU - Safe, S.
PY - 1982/9
Y1 - 1982/9
N2 - The effects of structure on the activity of 15 polychlorinated biphenyl (PCB) isomers and congeners as inducers of cytochrome P-448-dependent monooxygenases in rat hepatoma cell cultures was investigated. All the PCBs which have previously been classified as aryl hydrocarbon hydroxylase (AHH) inducers in the immature male Wistar rat also induced benzo[a]pyrene hydroxylase and ethoxyresorufin (ER) O-deethylase activity in the rat hepatoma H-4-II-E cells. The relative activities of the compounds were evaluated by comparing the doses required to half-maximally induce the two enzyme activities. The most potent PCB inducer, 3,3',4,4',5-pentachlorobiphenyl, exhibited molar EC50 values of 2.48 · 10-10 and 2.40 · 10-10 for the induction of ER O-deethylase and benzo[a]pyrene hydroxylase enzyme activities, respectively. These values were only 3- to 4-fold lower than the data obtained for the highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The relative activities of the PCB congeners as inducers of cytochrome P-448-dependent monooxygenase in vitro were similar to their potencies as microsomal enzyme inducers in the immature male rat.
AB - The effects of structure on the activity of 15 polychlorinated biphenyl (PCB) isomers and congeners as inducers of cytochrome P-448-dependent monooxygenases in rat hepatoma cell cultures was investigated. All the PCBs which have previously been classified as aryl hydrocarbon hydroxylase (AHH) inducers in the immature male Wistar rat also induced benzo[a]pyrene hydroxylase and ethoxyresorufin (ER) O-deethylase activity in the rat hepatoma H-4-II-E cells. The relative activities of the compounds were evaluated by comparing the doses required to half-maximally induce the two enzyme activities. The most potent PCB inducer, 3,3',4,4',5-pentachlorobiphenyl, exhibited molar EC50 values of 2.48 · 10-10 and 2.40 · 10-10 for the induction of ER O-deethylase and benzo[a]pyrene hydroxylase enzyme activities, respectively. These values were only 3- to 4-fold lower than the data obtained for the highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The relative activities of the PCB congeners as inducers of cytochrome P-448-dependent monooxygenase in vitro were similar to their potencies as microsomal enzyme inducers in the immature male rat.
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U2 - 10.1016/0378-4274(82)90142-4
DO - 10.1016/0378-4274(82)90142-4
M3 - Article
C2 - 6817473
AN - SCOPUS:0020423472
SN - 0378-4274
VL - 13
SP - 87
EP - 93
JO - Toxicology Letters
JF - Toxicology Letters
IS - 1-2
ER -