title: Some heterocyclic aromatic compounds are Ah receptor agonists in the DR-CALUX assay and the EROD assay with RTL-W1 cells.
abstract: OBJECTIVE
  Heterocyclic aromatic compounds containing nitrogen, sulfur, or oxygen heteroatoms (NSO-HET) have been detected in air, soil, marine, and freshwater systems. However, only few publications are available investigating NSO-HET using in vitro bioassays. To support better characterization of environmental samples, selected NSO-HET were screened for dioxin-like activity in two bioassays.
  
  
  METHODS
  The present study focuses on the identification and quantification of dioxin-like effects of 12 NSO-HET using the DR-CALUX assay, and the 7-ethoxyresorufin-O-deethylase (EROD) assay with the permanent fish liver cell line RTL-W1. Changes of the total medium compound concentrations during the test procedure due to, e.g., sorption or volatilization were quantified using GC/MS.
  
  
  RESULTS
  The NSO-HET benzofuran, 2,3-dimethylbenzofuran, dibenzofuran, dibenzothiophen, acridine, xanthene, and carbazole caused a response in the DR-CALUX assay. Only benzofuran and 2,3-dimethylbenzofuran were also positive in the EROD assay. All other compounds were inactive in the EROD assay. Relative potency (REP) values ranged from (2.80 ± 1.32) · 10(-8) to (3.26 ± 2.03) · 10(-6) in the DR-CALUX and from (3.26 ± 0.91) · 10(-7) to (4.87 ± 1.97) · 10(-7) in the EROD assay.
  
  
  CONCLUSIONS
  The REP values were comparable to those of larger polycyclic aromatic hydrocarbons, e.g., fluoranthene and pyrene. Thus, and because of the ubiquitous distribution of heterocyclic aromatic compounds in the environment, the provided data will further facilitate the bioanalytical and analytical characterization of environmental samples towards these toxicants.
authors: Aquatic Toxicology and Ecology Section, Department of Zoology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
authors: Gunnar
authors: G
authors: Hinger
authors: Markus
authors: M
authors: Brinkmann
authors: Kerstin
authors: K
authors: Bluhm
authors: Anne
authors: A
authors: Sagner
authors: Helena
authors: H
authors: Takner
authors: Adolf
authors: A
authors: Eisenträger
authors: Thomas
authors: T
authors: Braunbeck
authors: Magnus
authors: M
authors: Engwall
authors: Andreas
authors: A
authors: Tiehm
authors: Henner
authors: H
authors: Hollert
mesh_terms: D000818:Animals; D001681:Biological Assay; D002460:Cell Line; D019363:Cytochrome P-450 CYP1A1 / Q000737:chemistry; D004785:Environmental Pollutants / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D008401:Gas Chromatography-Mass Spectrometry; D006571:Heterocyclic Compounds / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D008099:Liver / Q000187:drug effects; D009584:Nitrogen / Q000737:chemistry; D017686:Oncorhynchus mykiss / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry; D051381:Rats; D018336:Receptors, Aryl Hydrocarbon / Q000819:agonists*; D013455:Sulfur / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D006571:Heterocyclic Compounds; D018336:Receptors, Aryl Hydrocarbon; D013455:Sulfur; D019363:Cytochrome P-450 CYP1A1; D009584:Nitrogen; D010100:Oxygen