7-Ethoxyresorufin

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. 

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. 

Sanderson, J.T., S.W. Kennedy, and J.P. Giesy. 1998. In vitro induction of ethoxyresorufin-O-deethylase and porphyrin by halogenated aromatic hydrocarbons in avian primary hepatocytes. Environ. Toxicol. Chem. 17 2006-2018. 

Benzo[a]pyrene Hydroxylase Ethoxyresorufin- O-deethy lase... 

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... 

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)... 

Kennedy, S.W., A. Lorenzen, C.A. James, and R.J. Norstrom. 1992. Ethoxyresorufin-O-deethylase (EROD) and porphyria induction in chicken embryo hepatocyte cultures — a new bioassay of PCB, PCDD, and related chemical contamination in wildlife. Chemosphere 25 193-196. 

Bennett, B. M., MacDonald, B. J., Nigam, R., Long, P. G., Simon, W. C., Inhibition of nitrovasodilator- and acetylcholine-induced relaxation and cyclic GMP accumulation by the cytochrome P450 substrate 7-ethoxyresorufin. Can. J. Physiol. Pharmacol. 70 (1992), p. 1297-1303... 

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]. 

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 ... 

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. 

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... 

Burke, M. D. and Mayer, R. T. Ethoxyresorufin direct fluorimetric assay of a microsomal 0-dealkylation which is preferentially inducible by 3-methylcholanthrene. Drug Metab. Dispos. (1974) 2 583-588. 

Arylhydrocarbon (benzo[a]pyrene) hydroxylase, benzphetamine-N-demethylation, ethylmorphine-N-demethylation, ethoxycoumarin-0-deethylation and ethoxyresorufin-0-deethylation were performed by published procedures (31,32,33,34), but optimized for use with trout microsomes as described previously (30, 35). Hemoprotein P-450 was determined by the procedure of Estabrook et al. (36) to avoid spectral interference by hemoglobin. Microsomal protein content was estimated either by the method of Ross and Shatz (37) or Lowry et al. (38), using bovine serum albumin standards. 

On the other hand, the metabolism of benzo[a]pyrene, ethoxy-coumarin and ethoxyresorufin, which are preferentially oxidized by rodent cytochrome P -450, was greatly induced by the polyhalogenated biphenyls and 3-naphthoflavone. Despite large changes in... 

In this study, we have utilized 2,2, 4,4 -tetrachlorobiphenyl and 3,3, 4,4 -tetrachlorobiphenyl as representative non-coplanar and coplanar isomers respectively. The 3,3, 4,4 -tetrachlordbi-phenyl isomer (0.3mmole/kg) induced ethoxycoumarin-and ethoxy-resorufin-O-deethylations in the rainbow trout to a similar extent as did Aroclor 1242 (Table III). However, the non-coplanar 2,2 -4,4 -tetrachlorobiphenyl was without effect upon any of the monooxygenase activities examined. Cytochrome P -450-like activity as determined by ethoxyresorufin-O-deethylation was increased by the planar 3,3, 4,4 -tetrachlorobiphenyl while cytochrome P-450-like activity (benzphetamine-N-demethylation) was unaffected. 

Figure 6.2 Ethoxyresorufin-O-deethylase(EROD) induction in H4IIE rat hepatoma cells exposed to an SPMD dialysate. Four Standard SPMDs were deployed for a 28 day period in Bayou Meto, Arkansas. Doses of dialysate were normalized to gram-equivalents of triolein per mg of cellular protein. This figure was generated by Don Tillitt, USGS-CERC, Columbia, MO, USA and is reprinted with permission from the American Petroleum Institute (Huckins et al., 2002).

Whyte, J.J. Jung, R.E. Schmitt, C.J. Tillitt, D.E. 2000, Ethoxyresorufin-O-deethylase (EROD) activity in fish as a biomaiker of chemical exposure. Crit. Rev. Toxicol. 30 347-570. 

Figure 8.6 Induction of significant activity in the ethoxyresorufin-O-deethylase (EROD) screen by an extract of an SPMD sample from Lake Shkodra/Skadar. Reprinted from Rastalletal. (2004a), copyright (2004) reproduced with permission from Environmental Science and Pollution Research.

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