Pituitary as a target organ for toxic effects of P4501A1 inducing chemicals

Andersson, Tommy; Förlin, Lars; Olsen, Sue; Fostier, Alexis; Breton, Bernard

doi:10.1016/0303-7207(93)90260-q

Cited by 27 publications

(9 citation statements)

References 32 publications

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“…22, 2003 2781 they found no significant relationships between reduced steroid hormone concentrations and gonadal development [11,12]. Increased androgen production in fish has also been documented in male rainbow trout (Salmo garidneri) exposed to the PAH beta-naphthoflavone (␤NF) [36,37]. The sites of action of specific PAHs on steroid production are unknown, and it will be more difficult to assess the effects of oil sands-related PAHs because of the complexity and diversity of these mixtures throughout the oil sands area.…”

Section: Discussionmentioning

confidence: 99%

Using reproductive endpoints in small forage fish species to evaluate the effects of athabasca oil sands activities

Tetreault

McMaster

Dixon

et al. 2003

Enviro Toxic and Chemistry

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The main objective of this study was to evaluate the influence of naturally occurring oil sands-related compounds (OSRC) on reproductive function in fish in order to assess the impacts of anthropogenic point-source inputs. The health of slimy sculpin (Cottus cognatus) and pearl dace (Semotilus margarita) collected from the Alberta Athabasca Oil Sands (Canada) watershed were examined. Two rivers were selected for study: the Steepbank and the Ells. These rivers originate outside the oil sands formation, where fish are unexposed (Ref), exposed to naturally occurring oil sands-related compounds (Nat), or exposed to naturally occurring compounds as well as adjacent to surface mining activity (Dev). Assessment endpoints included gonadosomatic indices (GSI), fecundity, and in vitro gonadal steroid production. In vitro gonadal incubations demonstrated lower levels of steroid production at sites along the Steepbank River within the oil sands deposit. Hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity, an indicator of exposure to OSRC, was elevated twofold at the site with natural compounds and up to 10-fold at the site adjacent to development compared to EROD activity in fish from the reference site. Fish collected in the Ells River had a threefold induction in EROD activity but no significant reduction in steroid production when compared to reference fish. No consistent alterations in gonadal development were seen in fish collected from sites within the oil sands deposit. This research in the Athabasca River basin provides baseline information of the health of fish populations within the oil sands deposit prior to further development in the area.

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Section: Discussionmentioning

confidence: 99%

Using reproductive endpoints in small forage fish species to evaluate the effects of athabasca oil sands activities

Tetreault

McMaster

Dixon

et al. 2003

Enviro Toxic and Chemistry

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“…In support of this, AhR ligand increases the levels of gonadotropine II and adrenocorticotropic hormone produced in pituitary. [24][25][26] From reports above mentioned, one possibility with respect to the reducing mechanism of GGA is raised that GGA exerts its protective effects by affecting a target(s) located downstream of the AhR pathways.…”

Section: Discussionmentioning

confidence: 99%

Reduction of the Toxicity of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Mice Using an Antiulcer Drug, Geranylgeranylacetone

Ishida

Oshimo

Nishimura

et al. 2004

Biological & Pharmaceutical Bulletin

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The protective effect of geranylgeranylacetone (GGA), an antiulcer drug, against the acute toxicity and teratogenicity produced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was examined in C57BL/6J mice. When mice were co-treated, GGA reduced the loss of body weight gain and lethality produced by TCDD but hepatomegaly and thymic atrophy were not improved. Additionally, no protective effect of GGA was observed in the formation of cleft palate and hydronephrosis in mouse fetuses caused by maternal exposure to TCDD. To clarify the reducing mechanism by GGA, the Hsp70.1 mRNA levels in liver and intestine were analyzed. However, it was difficult to explain the effect of GGA from the induction of Hsp70.1. GGA had also no effect on the induction of hepatic ethoxyresorufin O-deethylase activity by TCDD. These data suggest that GGA exhibits a protective effect against some forms of dioxin toxicity by a mechanism without involving inhibition of arylhydrocarbon receptor activation.

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“…The presence of CYP Al in brain endothelial cells was also demonstrated in scup from PAH-polluted areas . Furthermore, male rainbow trout pituitary CYP 1AI was found to be elevated by a PAH-type inducer (13-naphthoflavone, BNF) (Andersson et al 1993). Pituitary cells containing inducible CYP lAl were identified as gonadotrophs containing gonadotropin II, indicating one possible link between reproductive disturbances and PAH exposure.…”

Section: Introductionmentioning

confidence: 99%

Distribution and induction of cytochrome P450 1A1 in the rainbow trout brain

Andersson

Goksøyr

1994

Fish Physiol Biochem

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Cytochrome P450 (CYP) 1A1 participates in the activation as well as detoxification of environmental pollutants such as aromatic hydrocarbons. This CYP form is also efficiently induced by aromatic hydrocarbons. The presence of CYP 1A1 in the brain might thus be of physiological and toxicological importance. In the present investigation on rainbow trout, the distribution of 7-ethoxyresorufin-O-deethylase (EROD) activity, a cytochrome CYP 1A1 catalyzed reaction, was measured in whole tissue homogenates from brain parts. In control fish, a relatively high activity was found in the rainbow trout olfactory bulb compared to the other brain parts. Although an EROD induction (3 to 7-fold) by β-naphthoflavone (BNF) was recorded in all brain parts from the rainbow trout, the highest induced activity was measured in the olfactory bulbs. To ascertain the distribution of EROD activity in cells, whole brain tissue was subfractionated by differential centrifugation. The fractionation scheme separated mitochondria (P2 fraction) and microsomes (P3 fraction) as determined by marker enzymes and electron microscopy. In control rainbow trout, a low EROD activity could be measured in the P2 fraction. BNF induced the EROD activity in both P2 and P3 fractions. Western blotting showed the induction by BNF of a protein band in the P2 and P3 fractions with a molecular mass around 58,000 when highly specific anti-cod CYP 1A1 antibodies were used. ELISA measurements confirmed the induction of CYP 1A1 protein in the rainbow trout brain subcellular fractions.

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Pituitary as a target organ for toxic effects of P4501A1 inducing chemicals

Cited by 27 publications

References 32 publications

Using reproductive endpoints in small forage fish species to evaluate the effects of athabasca oil sands activities

Using reproductive endpoints in small forage fish species to evaluate the effects of athabasca oil sands activities

Reduction of the Toxicity of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Mice Using an Antiulcer Drug, Geranylgeranylacetone

Distribution and induction of cytochrome P450 1A1 in the rainbow trout brain

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