Aryl hydrocarbon hydrolase

CYP3A5 7q21.1 Cytochrome P450, Aryl hydrocarbon hydrolase Aflatoxin B1, anthracychne, cis- Blood coagulation CYPi3 ... 

Poland A, Glover E, Kende AS. 1976. Stereospecific, high affinity binding of 2,3,7,8-tetra-chlorodibenzo-p-dioxin by hepatic cytosol. Evidence that the binding species is receptor for induction of aryl hydrocarbon hydrolase. J Biol Chem 251 4936-4946. 

The azo compound, 3,3, 4,4 -tetrachloroazobenzene, bears a steric resemblance to TCDD. It induces aryl hydrocarbon hydrolase activity in mice and chick embryos. It may be acnegenic and it is a potential carcinogen (19). It has been detected as a contaminant in formulations of the herbicide, propanil (3,4-dichloropropionanilide). Azobenzenes have also been detected in commercial samples of the urea... 

Certain PCDDs and PCDFs act as very powerful inducers of the MFO system and give rise to de novo synthesis of CYP1A1, a cytochrome P450 isozyme associated with aryl hydrocarbon hydrolase (AHH or Ah), and ethoxyresorufin O-deethylase (EROD), a common biomarker for PCDD exposure. 

Dermal treatment of healthy volunteers with 10% coal tar for 4 days produced an 18-fold induction of CYP1A1 mRNA levels in coal-tar-treated skin (Li et al. 1995). In vitro incubation of DNA with coal tar fume concentrates in the presence of mouse and yeast microsomes expressing various cytochrome P450 isoforms or the aryl hydrocarbon hydroxylase receptor (AHR) demonstrated that coal tar fume condensates require metabolic activation to produce DNA adducts (Genevois et al. 1998). Both the AHR and CYP1A were involved in the metabolism of coal tar fume condensate. It was also shown that the reactive metabolites formed by CYP1A are substrates for microsomal epoxide hydrolase. 

LOEL 250 mg/kg/day (mice) 125 mg/kg/day [10, 11] (rats) hepatocellular hypertrophy NOEL 10 mg/kg/day increases in liver and [1] kidney weights, increases in the incidence of hepatocellular hypertrophy, increases in thyroidparathyroid weights, hypertrophy and hyperplasia of the thyroid high incidences of trace-to-mild chronic nephritis in kidneys of male rats and increased pigmentation of the renal tubules in female rats LOAEL = 312 mg/kg/day (rats) 125 mg/kg/day [10, 11] (mice) hepatocellular neoplasms and adenomas or adenocarcinomas of the liver mononuclear cell leukemia adenomas or hyperplasia of the renal tubular cells in exposed male rats follicular cell adenomas or carcinomas of the thyroid in exposed female rats and female mice alveolar/bronchiolar adenomas or carcinomas in male mice 52 mg/kg Paroil intestinal activities of aryl [13] hydrocarbon hydroxylase (increase), UDP-glucuronosyltransferase (decrease) and epoxide hydrolase (increased)... 

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