[Effects of 3-methylsulphonyl-4,5,3',4-tetrachlorobiphenyl and 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity].
First, we examined the effects of 3-methylsulphonyl-4,5,3',4',-tetrachlorobiphenyl (3-MSF-TCB, 1.5 ppm) and 7,8-benzoflavone (ANF, 1.4 ppm) on aryl hydrocarbon hydroxylase (AHH) activity in cultured human lymphoblastoid cells and we have obtained the following results: (1) 3-MSF-TCB preferentially inhibited the enzyme activity induced by 2,3,4,7,8-pentachlorodibenzofuran (PenCDF) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and slightly stimulated the enzyme activity induced by 3-methylcholanthrene (MC). (2) ANF reduced well the AHH activities induced by all the three enzyme inducers and more strongly inhibited the PenCDF- or TCDD-induced enzyme activity (about 89%). (3) About 64 and 76% of basal (uninduced) AHH activity was lowered by 3-MSF-TCB and ANF, respectively. Second, we investigated the effect of 3-MSF-TCB (1.5-45 ppm) and ANF (1.4-42 ppm) on AHH activity of hepatic microsomes from the Ah nonresponsive (DDD) and responsive (C3H) strains of mice and we have got the following results: (1) 3-MSF-TCB and ANF enhanced or reduced the enzyme activity depending on both their concentrations and kinds of microsomes, namely, those prepared from untreated mice (control-microsomes) and mice treated with MC (MC-microsomes) or TCDD (TCDD-microsomes). (2) ANF showed higher potency for both the enhancement and the inhibition of the enzyme activity than 3-MSF-TCB. (3) The AHH activity of TCDD-microsomes seemed to be more greatly reduced with either 3-MSF-TCB or ANF than that of MC-microsomes. (4) The effects of 3-MSF-TCB and ANF on the enzyme activity of MC-microsomes of DDD mice and of control-microsomes of C3H mice.
Nagayama
J
J
Mohri
N
N
Haraguchi
K
K
Masuda
Y
Y
Kiyohara
C
C
Hirohata
T
T
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001571:Benzoflavones / Q000494:pharmacology*; D002478:Cells, Cultured; D005419:Flavonoids / Q000494:pharmacology*; D008214:Lymphocytes / Q000201:enzymology*; D051379:Mice; D008862:Microsomes, Liver / Q000201:enzymology*; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*
D001571:Benzoflavones; D005419:Flavonoids; C053780:3-methylsulfonyl-4,5,3',4'-tetrachlorobiphenyl; C011512:alpha-naphthoflavone; D011078:Polychlorinated Biphenyls; D001189:Aryl Hydrocarbon Hydroxylases