In vivo effect of 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity of mouse liver microsomes.
In vivo administration of 3-methylcholanthrene (MC) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produced much higher hepatic microsomal aryl hydrocarbon hydroxylase (AHH) induction than 7,8-benzoflavone (7,8-BF) in both aromatic hydrocarbon (Ah)-responsive and nonresponsive strains of mice. Simultaneous treatment or pre-treatment with 7,8-BF produced an inhibitory effect on AHH induction by MC or TCDD (i.e., the degrees of the inhibition, with TCDD, were 28% in the Ah-responsive strain C57BL/6N (C57) mice and 45% in the nonresponsive strain DDD;Qdj (DDD) mice). However, posttreatment with 7,8-BF was inclined to promote the induction of AHH by MC or TCDD (i.e., the degrees of the enhancement, with MC, were 15% in C57 mice and 45% in DDD mice). These results may suggest that the inhibitory effect of 7,8-BF in vivo is limited not to the combination of AHH inducer (MC or TCDD) but to its application of timing or Ah responsiveness.
Kiyohara
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C
Department of Public Health, Faculty of Medicine, Kyushu University, Fukuoka-shi, Japan.
Hirohata
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T
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001571:Benzoflavones / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects; D008748:Methylcholanthrene / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology
D001571:Benzoflavones; D000072317:Polychlorinated Dibenzodioxins; D008748:Methylcholanthrene; C011512:alpha-naphthoflavone; D001189:Aryl Hydrocarbon Hydroxylases