Ethoxyresorufin <9-deethylase activity

One AHH fluorescence unit equals the fluorescence intensity of a 3 ug/ml quinine sulfate 2H20 in 0.1 N sulfuric acid solution (excitation A 425 nm, emission a 555 nm). 7-Ethoxyresorufin deethylase activity was assayed essentially as described by Burke and Mayer (13) at a 7-ethoxyresorufin concentration of 2 yM, a final pH of 7.8, and an incubation temperature of 30° (14). 

One of our more interesting observations is illustrated in Table III. The administration of DBA to winter flounder increased hepatic microsomal AHH and 7-ethoxyresorufin deethylase activities as expected, and AHH activity was strongly inhibited in the DBA-treated flounder by 10" M a-naphthoflavone as we have previously reported for both little skate (4) and sheepshead (9). However, the presence of high AHH and 7-ethoxyresorufin deethylase activities in one control flounder, and the inhibition of AHH activity by a-naphthoflavone in this animal suggested that the hepatic microsomal MFO system of this fish was already induced. 

Kannan, K., D.L. Villeneuve, A.L. Blankenship, and J.P. Giesy. 1998b. Interaction of tributyltin with 3,3, 4,4, 5-pentachlorobiphenyl-induced ethoxyresorufin O-deethylase activity in rat hepatoma cells. Jour. Toxicol. Environ. Health 55A 373-384. 

Single ip injection of 30 mg PCB 118/kg BW to immatures. Fish killed 4 days later and liver analyzed Liver EROD (7-ethoxyresorufin O-deethylase) activity was 5.6 times higher than controls AHH activity was 2.7 times higher than controls 5... 

M (cytoplasmic vacuolation, accentuation of zonation, increased ethoxyresorufin-O-deethylase activity) 402.9 F (cytoplasmic vacuolation, accentuation of zonation, increased ethoxyresorufin-O-deethylase activity)... 

An MRL of 0.4 mg/kg/day has been derived for intermediate-duration oral exposure to di-/ -octylphthalate. This MRL is based on a NOAEL of 40.8 mg/kg/day for liver effects that were observed in rats fed di-w-octylphthalate in the diet at a dose of 350.1 mg/kg/day (males) or 402.9 mg/kg/day (females) (Poon et al. 1995). These hepatic effects consisted of a statistically significant (p<0.05) increase in hepatic ethoxyresorufin-0-deethylase activity and histological changes in hepatic architecture, including accentuation of zonation and perivenous cytoplasmic vacuolation. Thyroid toxicity (decreased colloid density and reduced follicle size) was also noted at this concentration. The NOAEL was divided by an uncertainty factor of 100 (10 for extrapolation from animals to humans and 10 for human variability). Support for the use of hepatic toxicity as the basis of the intermediate MRL is provided by other studies that show necrosis and other fatty changes after acute- and intermediate-duration exposure of rats (DeAngelo et al. 1986 Lake et al. 1984, 1986 ... 

BENZO(a)PYRENE HYDROXYLASE (AHH) AND 7-ETHOXYRESORUFIN DEETHYLASE (7-ERF) ACTIVITIES IN.LIVER HOMOGENATE OF FEMALE WINTER FLOUNDER SEPARATED INTO ARBITRARY GROUPS BASED ON AHH ACTIVITY... 

Golor G, Neubert D. 1989. EROD (ethoxyresorufin-o-deethylase) activity in rat liver tissue after application of TCDD and OCDD alone and in combination [Abstract]. Naunyn Schmiedeberg s Arch Pharmacol 339 10. 

Schulz-Schlage T, Golor G, Stahlmann R. 1992. Biological effect of high doses of TCDD in the marmoset monkey, Callithrixjacchus, Plateau of ethoxyresorufin O-deethylase activity in liver microsomes. Chemosphere 25(7-10) 991-995. 

Weber LW, Lebofsky M, Stahl BU, et al. 1992b. Comparative toxicity of four chlorinated dibenzo-p-dioxins (CDDs) and their mixture. Part III Structure-activity relationship with increased plasma tryptophan levels, but no relationship to hepatic ethoxyresorufin o-deethylase activity. Arch Toxicol 66(7) 484-488. 

Bols, N.C., K. Schirmer, E.M. Joyce, D.G. Dixon, B.M. Greenberg and J.J. Whyte. Ability of polycyclic aromatic hydrocarbons to induce 7-ethoxyresorufin-o-deethylase activity in a trout liver cell line. 

Schirmer, K., D.J. Tom, N.C. Bols and J.P. Sherry. Ability of fractionated petroleum refinery effluent to elicit cyto- and photocytotoxic responses and to induce 7-ethoxyresorufin-o-deethylase activity in fish cell lines. Sci. Total Environ. 271 61-78, 2001. 

Tom, D.J., L.E.J. Lee, J. Lew and N.C. Bols. Induction of 7-ethoxyresorufin-o-deethylase activity by planar chlorinated hydrocarbons and polycyclic aromatic hydrocarbons in cell lines from the rainbow trout pituitary. Comp. Biochem. Physiol. 128A 185-198, 2001. 

Nacci, D., L. Coiro, A. Kuhn, D. Champlin, W. Munns, J. Specker and K. Cooper. Nondestructive indicator of ethoxyresorufin-O-deethylase activity in embryonic fish. Environ. Toxicol. Chem. 17 2481—2486,1998. 

Huang Y-W, Karasov WH, Patnode KA, et al. 1999. Exposure of northern leopard frogs in the Green Bay ecosystem to polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans is measured by direct chemistry but not hepatic ethoxyresorufin-O-deethylase activity. Environ Toxicol Chem 18(10) 2123-2130. 

Achazi. R. K., Chroscz, G.. Heimig. E.. Neunaber. R., and Steudel, 1. (1994). A high molecular regulator of 7-ethoxyresorufin-o-deethylase activity in fish. Comp. Biodiem. Physiol. C 108, 243-256. 

Table 5 Chlorinated polycyclic aromatic hydrocarbons (CIPAH) activity expressed as (a) EROD (ethoxyresorufin-O-deethylase) activity as the relative intensity of ClPAH-mduced cytochrome P450 (CYP) activity in human breast cancer MCF-7 cells [228] (b) environmental fate [Bioaccumulation aquatic] in Pimephales promelas over 96 h [10 L/kg wet] (c) ecotoxicological information [Aquatic Toxicity] LC50 for Pimephales promelas after 96 h [10 mg/L] and (d) carcinogenity in rats, TD50 [10 mol/kg]...

P-450 or P-450 reductase, induction responses, spectral and binding studies, and microsomal (endoplasmic reticulum) location and requirement for NADPH, O2 etc. (Burke 1981). The induction of a specific isoenzyme of cytochrome P-450 can be detected in crude microsomal preparations by antibodies or MFO reactions specific to that isoenzyme, e.g. the 3-methylcholanthrene (3MC)-inducible type (P4501A subfamily) is detected by the ethoxyresorufin 0-deethylase (EROD) assay (Phillipson et al. 1984,1985 Stegeman et al. 1986). The presence of more than one isoenzyme of cytochrome P-450 in crude microsomes can result in multiphasic kinetics towards a particular substrate, e.g. 7-ethoxycoumarin O-deethylase activity (ECOD) (Lu and West 1980). 

The most sensitive effect of in ovo exposures was induction of hepatic ethoxyresorufin O-deethylase (EROD) activity in 1-day-old chicks, with an ED50 dose of 0.312 pg/kg FW egg. 

Scup, Stenotomus chrysops injected intraperitoneally with 1,5, or 10 mg/kg BW of PCBs 77, 105, 118, 128, or 138 and examined tor increases in ethoxyresorufin O-deethylase (EROD) activity, immunodetectable cytochrome P-450E (the EROD catalyst in scup) and in vitro translatable mRNA for P-450E... 

Fed diets for 4 weeks containing daily doses equivalent to 3 mg PCB 105/kg BW, 0.05 mg PCB 126/kg BW, or 4.0 mg PCB 153/kg BW. Birds were killed 3 days after final treatment and livers analyzed for porphyrins, PCB residues, and activities of ethoxyresorufin O-deethylase-(EROD), aminopyrine-/V-demethylase (APND), and aldrin epoxidase (AE)... 

The measurement of the ethoxyresorufin-O-deethylase (EROD) activity is another sensitive parameter to detect the effects of paper mill industrial effluents on living organisms in the receiving waters. The EROD activity is a measure of the activity of the cytochrome P-450 enzyme system, which plays a central role in the transformation and elimination of xenobiotics. Increased EROD activity has been shown as far as 40 km from pulp mills, and EROD induction in fish caused by pulp mill effluents remains after biological treatment [60]. It is specified that EROD activity and erythrocytic nuclear abnormalities are induced by abietic and dehydroabietic acid [60]. 

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