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Induction of hepatic CYP1A in channel catfish increases binding of 2-aminoanthracene to DNA in vitro and in vivo.

Publication ,  Journal Article
Watson, DE; Reichert, W; Di Giulio, RT
Published in: Carcinogenesis
August 1998

Data are presented from in vitro and in vivo studies that indicate cytochrome P4501A (CYP1A) in channel catfish (Ictalurus punctatus) hepatic tissue activates 2-amino-anthracene (AA) to a reactive metabolite that binds to DNA. Channel catfish were injected i.p. with vehicle or 10 mg/kg beta-naphthoflavone (betaNF) on two consecutive days. Two days after the final injection of vehicle or betaNF, vehicle or [3H]AA was injected i.p. at 10 mg/kg, creating four different treatments: vehicle only, betaNF only, [3H]AA only, and betaNF/[3H]AA. Hepatic tissue was examined for CYP1A-associated ethoxyresorufin-O-de-ethylase (EROD) activity, and for DNA adducts at 1, 2, 4 and 7 days following administration of vehicle or [3H]AA. Hepatic EROD activity in betaNF-treated fish was 17-fold higher at day 0 and remained significantly greater than untreated animals for the 7-day experiment. Hepatic DNA adducts, as measured by tritium-associated DNA, ranged from 4.8 to 8.6 pmol/mg DNA in vehicle-pretreated fish injected with [3H]AA, but ranged from 12.6 to 22.7 pmol/mg DNA in betaNF-pretreated fish injected with [3H]AA. Thus, pretreatment with betaNF significantly increased binding of [3H]AA to hepatic DNA in vivo at all four times. Analysis by 32P-post-labeling and thin layer chromatography of hepatic DNA from channel catfish treated with AA revealed two major and several minor spots, which are indicative of DNA adduct formation. Hepatic microsomes from betaNF-pretreated fish were more effective at catalysing the binding of [3H]AA to DNA in vitro than were microsomes from non-treated fish. In addition, binding was decreased by the CYP1A inhibitor 3,3',4,4'-tetrachlorobiphenyl. Collectively, these data demonstrate that CYP1A is involved in the activation of AA in channel catfish.

Duke Scholars

Published In

Carcinogenesis

DOI

EISSN

1460-2180

ISSN

0143-3334

Publication Date

August 1998

Volume

19

Issue

8

Start / End Page

1495 / 1501

Related Subject Headings

  • beta-Naphthoflavone
  • Time Factors
  • Oncology & Carcinogenesis
  • Microsomes, Liver
  • Ictaluridae
  • Enzyme Inhibitors
  • Enzyme Induction
  • DNA Adducts
  • DNA
  • Cytochrome P-450 CYP1A1
 

Citation

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MLA
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Watson, D. E., Reichert, W., & Di Giulio, R. T. (1998). Induction of hepatic CYP1A in channel catfish increases binding of 2-aminoanthracene to DNA in vitro and in vivo. Carcinogenesis, 19(8), 1495–1501. https://doi.org/10.1093/carcin/19.8.1495
Watson, D. E., W. Reichert, and R. T. Di Giulio. “Induction of hepatic CYP1A in channel catfish increases binding of 2-aminoanthracene to DNA in vitro and in vivo.Carcinogenesis 19, no. 8 (August 1998): 1495–1501. https://doi.org/10.1093/carcin/19.8.1495.
Watson DE, Reichert W, Di Giulio RT. Induction of hepatic CYP1A in channel catfish increases binding of 2-aminoanthracene to DNA in vitro and in vivo. Carcinogenesis. 1998 Aug;19(8):1495–501.
Watson, D. E., et al. “Induction of hepatic CYP1A in channel catfish increases binding of 2-aminoanthracene to DNA in vitro and in vivo.Carcinogenesis, vol. 19, no. 8, Aug. 1998, pp. 1495–501. Epmc, doi:10.1093/carcin/19.8.1495.
Watson DE, Reichert W, Di Giulio RT. Induction of hepatic CYP1A in channel catfish increases binding of 2-aminoanthracene to DNA in vitro and in vivo. Carcinogenesis. 1998 Aug;19(8):1495–1501.
Journal cover image

Published In

Carcinogenesis

DOI

EISSN

1460-2180

ISSN

0143-3334

Publication Date

August 1998

Volume

19

Issue

8

Start / End Page

1495 / 1501

Related Subject Headings

  • beta-Naphthoflavone
  • Time Factors
  • Oncology & Carcinogenesis
  • Microsomes, Liver
  • Ictaluridae
  • Enzyme Inhibitors
  • Enzyme Induction
  • DNA Adducts
  • DNA
  • Cytochrome P-450 CYP1A1