Aromatase activity in the ovary and brain of the eastern mosquitofish (Gambusia holbrooki) exposed to paper mill effluent.

Orlando, Edward F.; Davis, William P.; Guillette, Louis J.

doi:10.1289/ehp.02110s3429

Cited by 76 publications

(52 citation statements)

References 67 publications

(60 reference statements)

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“…The most frequently reported impact is the interference with the aromatase CYP19 system, which alters the plasma level of estrogens and leads to The effects of estrogenic and androgenic endocrine disruptors 307 disruption of estrogen-related biological processes (Cheshenko et al 2008). The disruption of steroid biotransformation has been observed in situ in wild fishes that were exposed to contaminated effluents (Munkittrick et al 1992(Munkittrick et al , 1994Orlando et al 2002;Noaksson et al 2003a, b) or to PCB (Förlin and Anderson 1984). For example, the level of P450-aromatase activity, the enzyme which catalyses the final conversion of testosterone into estrogen, was significantly lower in feral carp (Cyprinus carpio) at polluted sites, resulting in a change in the sex hormone ratio towards testosterone (Lavado et al 2004).…”

Section: Estrogen-and Androgen-like Endocrine Disrupting Contaminantsmentioning

confidence: 99%

The effects of estrogenic and androgenic endocrine disruptors on the immune system of fish: a review

2011

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During the last decade, a number of studies have shown that, in addition to their classically described reproductive function, estrogens and androgens also regulate the immune system in teleosts. Today, several molecules are known to interfere with the sex-steroid signaling. These chemicals are often referred to as endocrine disrupting contaminants (EDCs). We review the growing evidence that these compounds interfere with the fish immune system. These studies encompass a broad range of approaches from field studies to those at the molecular level. This integrative overview improves our understanding of the various endocrine-disrupting processes triggered by these chemicals. Furthermore, the research also explains why fish that have been exposed to EDCs are more sensitive to pathogens during gametogenesis. In this review, we first discuss the primary actions of sex-steroid-like endocrine disruptors in fish and the specificity of the fish immune system in comparison to mammals. Then, we review the known interactions between the immune system and EDCs and interpret the primary effects of sex steroids (estrogens and androgens) and their related endocrine disruptors on immune modulation. The recent literature suggests that immune parameters may be used as biomarkers of contamination by EDCs. However, caution should be used in the assessment of such immunotoxicity. In particular, more attention should be paid to the specificity of these biomarkers, the external/internal factors influencing the response, and the transduction pathways induced by these molecules in fish. The use of the well-known mammalian models provides a useful guide for future research in fish.

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Section: Estrogen-and Androgen-like Endocrine Disrupting Contaminantsmentioning

confidence: 99%

The effects of estrogenic and androgenic endocrine disruptors on the immune system of fish: a review

2011

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“…Brains, livers, and gonads were dissected and preserved accordingly (see below) for each of the measured endpoints (histology, biochemistry, or gene expression). Gonads and brains were weighed to the nearest 0.0001 g. Aromatase activity was measured in fresh samples of brain and ovary on a subset of female fish from each replicate and each treatment according to the methods of Orlando et al (2002). 17␤-Estradiol and testosterone were measured in the eviscerated carcass of fathead minnow (Heppell and Sullivan, 2000).…”

Section: Fish Collection Histological and Biochemical Assaysmentioning

confidence: 99%

“…Pre-vitellogenic (II) were undeveloped, perinucleolar oocytes at various stages or perinucleolar and cortical alveoli oocytes with no vitelline granules, vitellogenic were vitellogenic oocytes containing moderate numbers of vitelline granules or fully developed oocytes with an abundant amount of vitelline granules (III and IV), and mature were fully developed oocytes with germinal vesicles which had migrated to the animal pole (V). Aromatase activities were determined by the methods of Orlando et al (2002). Number of individuals in each treatment is given (n).…”

Section: Ovarian Stagingmentioning

confidence: 99%

Atrazine reduces reproduction in fathead minnow (Pimephales promelas)

et al. 2010

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a b s t r a c tAtrazine, the widely used herbicide, has shown to affect the hypothalamus-pituitary-gonad axis in certain vertebrate species, but few studies have examined reproductive effects of this chemical on fish. Our study was designed to evaluate a population endpoint (egg production) in conjunction with histological (e.g., gonad development) and biochemical (e.g., hormone production) phenotypes associated with atrazine exposure in fathead minnows. Adult virgin breeding groups of 1 male and 2 females were exposed to nominal concentrations of 0, 0.5, 5.0, and 50 g/L of atrazine in a flow-through diluter for 14 or 30 days. Total egg production was lower (19-39%) in all atrazine-exposed groups as compared to the controls. The decreases in cumulative egg production of atrazine treated fish were significant by 17-20 days of exposure. Reductions in egg production in atrazine treatment groups were most attributable to reduced numbers of spawning events with increased atrazine exposure concentrations. Gonad abnormalities were observed in both male and female fish of atrazine-exposed fish. Our results also indicate that atrazine reduces egg production through alteration of final maturation of oocytes. The reproductive effects observed in this study warrant further investigation and evaluation of the potential risks posed by atrazine, particularly feral populations of fish from streams in agricultural areas with high use of this herbicide.Published by Elsevier B.V.

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“…Some of these studies have reported abnormal steroid hormone levels, particular in alligators, indicating the possibility that these toxicants may block steroid hormone synthesis (Guillette et al 1994;Orlando et al 2002). For example, in vivo exposure of rainbow trout to alkylphenolic chemicals induced Vtg production, inhibited testicular growth and spermatogenesis (Jobling et al 1996;Le Gac et al 2001).…”

Section: Star and P450scc Expression In The Gonadsmentioning

confidence: 99%

Steroidogenic acute regulatory (StAR) protein and cholesterol side-chain cleavage (P450scc)-regulated steroidogenesis as an organ-specific molecular and cellular target for endocrine disrupting chemicals in fish

Arukwe

2008

Cell Biol Toxicol

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Biologically active steroids are synthesised de novo in specialised cells of several organs, including the adrenal gland, testis, ovary, brain, placenta and adipose tissue. Regardless of organ or tissue, the rate-limiting step in steroid hormone synthesis is the movement of cholesterol across the mitochondrial membrane (i.e. from the outer to the inner membrane) mediated by the steroidogenic acute regulatory (StAR) protein. Subsequent conversion of cholesterol to pregnenolone by cytochrome P450 side-chain cleavage (P450scc) represents the initiation of steroidogenesis. Chemically mediated disruption of StAR and P450scc expression may represent the first step in the sequence of related event cascades underlying xenoestrogen-induced toxicity and transmittable disturbances to the whole organism level. This may include, but is not limited to, alterations in sexual differentiation, growth, reproduction, development and metabolism. Despite the integral role of StAR and P450scc in acute steroidogenesis, and popular demand from regulatory agencies, bioassays for evaluating the effect of endocrine-disrupting chemicals have the potential to overlook chemicals that may modulate estrogenic responses through mechanisms that do not involve direct binding to estrogen receptors (ERs). In addition to their effect as direct ER agonists, the effects of endocrine disruptors may be evaluated and interpreted as interference with steroidogenesis and with the steroidal regulation of the normal development and function of juvenile, male and female individuals. Knowledge of these effects is scarce, indicating that relatively little is known about the mechanisms or mode-of-action of chemical alterations to steroidogenesis and their potential toxicity for wildlife species. In addition, analytical methods for the complete adaptation of these responses as biomarkers of response and effect are yet to be properly validated.

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Aromatase activity in the ovary and brain of the eastern mosquitofish (Gambusia holbrooki) exposed to paper mill effluent.

Cited by 76 publications

References 67 publications

The effects of estrogenic and androgenic endocrine disruptors on the immune system of fish: a review

The effects of estrogenic and androgenic endocrine disruptors on the immune system of fish: a review

Atrazine reduces reproduction in fathead minnow (Pimephales promelas)

Steroidogenic acute regulatory (StAR) protein and cholesterol side-chain cleavage (P450scc)-regulated steroidogenesis as an organ-specific molecular and cellular target for endocrine disrupting chemicals in fish

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