Effects of 3-methylsulphonyl-4,5,3',4'-tetrachlorobiphenyl and 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity in Ah responsive and Ah nonresponsive strains of mice.
In general, C57BL/6NQdj (C57) and DBA/2JCrj (DBA) strains of mice are considered to be the aryl hydrocarbon (Ah) responsive and Ah nonresponsive strains of mice, respectively, which are determined by whether the hepatic aryl hydrocarbon hydroxylase (AHH) activity is enhanced (Ah responsive) or not (Ah nonresponsive) after the treatment of 3-methylcholanthrene (MC). In this study, first, we examined that the Ah responsiveness was systemically regulated in the lungs and kidneys as well as in the liver and observed its systemic control in these three organs in the two strains of mice. Then, we prepared the hepatic microsomes of the two strains of mice after the treatment of MC (42 mg/kg, once), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 20 micrograms/kg, 6 times) and 2,3,4,7,8-pentachlorodibenzofuran (PenCDF 60 micrograms/kg, 6 times) in order to investigate the effects of 3-methylsulphonyl-4,5,3',4'-tetrachlorobiphenyl (3-MSF-TCB, 1.5-45 micrograms/ml) and 7,8-benzoflavone (ANF, 1.4-42 micrograms/ml) on the respective hepatic microsomal AHH activities and the following results were obtained. 1. As compared with the control enzyme activity, TCDD-induced AHH activity was the highest, PenCDF-induced one the second and MC-induced the lowest in both strains of mice. The inductions of the enzyme activity by these chemicals were much more remarkable in the Ah responsive C57 strain than those in the Ah nonresponsive DBA strain. 2. 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 control mice and mice treated with MC, TCDD or PenCDF.(ABSTRACT TRUNCATED AT 250 WORDS)
Nagayama
J
J
Laboratory of Environmental Medicine, School of Health Sciences, Kyushu University, Fukuoka.
Wada
K
K
Haraguchi
K
K
Masuda
Y
Y
Handa
S
S
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001571:Benzoflavones / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*
D001571:Benzoflavones; C053780:3-methylsulfonyl-4,5,3',4'-tetrachlorobiphenyl; C011512:alpha-naphthoflavone; D011078:Polychlorinated Biphenyls; D001189:Aryl Hydrocarbon Hydroxylases