Glucuronidation and glucosidation reactions in aquatic species in boreal regions

Hänninen, Osmo; Lindström-Seppä, Pirjo; Koivusaari, Ulla; Väisänen, Matti; Julkunen, Antero; Juvonen, Risto O.

doi:10.1042/bst0120013

Cited by 20 publications

(4 citation statements)

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“…has insignificant UDPG transferase activity (Yang et al 2002). The enzyme activity of some crustaceans is localized in the microsomal fraction of hepatopancreas or green glands (Elmamlouk and Gessner 1978;Hänninen et al 1984;Li and James 1993;Schell and James 1989;Väisänen et al 1983). Exposure of D. magna to diethylstilbestrol enhanced the formation of glucose conjugates of testosterone, but its presence was found to also slightly inhibit enzyme activity (Baldwin et al 1995).…”

Section: Glucose and Glucuronic Acid Transferasesmentioning

confidence: 98%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

137

102

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The ecotoxicological assessment of pesticide effects in the aquatic environment should normally be based on a deep knowledge of not only the concentration of pesticides and metabolites found but also on the influence of key abiotic and biotic processes that effect rates of dissipation. Although the bioconcentration and bioaccumulation potentials of pesticides in aquatic organisms are conveniently estimated from their hydrophobicity (represented by log K(ow), it is still indispensable to factor in the effects of key abiotic and biotic processes on such pesticides to gain a more precise understanding of how they may have in the natural environment. Relying only on pesticide hydrophobicity may produce an erroneous environmental impact assessment. Several factors affect rates of pesticide dissipation and accumulation in the aquatic environment. Such factors include the amount and type of sediment present in the water and type of diet available to water-dwelling organisms. The particular physiological behavior profiles of aquatic organisms in water, such as capacity for uptake, metabolism, and elimination, are also compelling factors, as is the chemistry of the water. When evaluating pesticide uptake and bioconcentration processes, it is important to know the amount and nature of bottom sediments present and the propensity that the stuffed aquatic organisms have to absorb and process xenobiotics. Extremely hydrophobic pesticides such as the organochlorines and pyrethroids are susceptible to adsorb strongly to dissolved organic matter associated with bottom sediment. Such absorption reduces the bioavailable fraction of pesticide dissolved in the water column and reduces the probable ecotoxicological impact on aquatic organisms living the water. In contrast, sediment dweller may suffer from higher levels of direct exposure to a pesticide, unless it is rapidly degraded in sediment. Metabolism is important to bioconcentration and bioaccumulation processes, as is detoxification and bioactivation. Hydrophobic pesticides that are expected to be highly stored in tissues would not be bioconcentrated if susceptible to biotic transformation by aquatic organisms to more rapidly metabolized to hydrophilic entities are generally less toxic. By analogy, pesticides that are metabolized to similar entities by aquatic species surely are les ecotoxicologically significant. One feature of fish and other aquatic species that makes them more relevant as targets of environmental studies and of regulation is that they may not only become contaminated by pesticides or other chemicals, but that they constitute and important part of the human diet. In this chapter, we provide an overview of the enzymes that are capable of metabolizing or otherwise assisting in the removal of xenobiotics from aquatic species. Many studies have been performed on the enzymes that are responsible for metabolizing xenobiotics. In addition to the use of conventional biochemical methods, such studies on enzymes are increasingly being conducted using immunochemical met...

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Section: Glucose and Glucuronic Acid Transferasesmentioning

confidence: 98%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

137

102

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“…Specific activities for DT-diaphorase, ALDH (18) and GST (26) were estimated from the linear portions of the continuoos curyes obtained over a 5 min period using the CPS kinetic mode of a Shimadzu 160 recording spectrophotometer. Activity of the microwma1 enzyme, uridine diphosphogtucuronyl transferase (UDPGT), with pnirrophenol as a abwate, was measured by the method of Castren aud Oikari (27) and was modified by &&ion of (0.2% final concentration) to solubilize p.otein (28). UDPGT and the cytosolic enzyme, 7-GT (Sigma; optimized for trout liver), were also assayed spwm@mmetrically by calculating the amount of product Ethoxyresoru6n-Odeethylase @ROD) &vity was monitored continuously for 5 min usinn a Shimadzu ~aan,fluxime& bv meeglrinn tlx formation of I.esorufin (29).…”

Section: Ulnacentrifuge L K R E S U L T a N T M I C R C S O M A L P mentioning

confidence: 99%

Biochemical and histochemical properties of hepatic tumors of rainbow trout, Oncorhynchus mykiss

Parker

Laurén²,

Hammock

et al. 1993

Carcinogenesis

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Biochemical and histochemical studies were conducted in aflatoxin B1-induced liver tumors in adult rainbow trout. Specific activities of the phase I enzymes, ethoxyresorufin-O-deethylase (EROD), microsomal and cytosolic epoxide hydrolase (mEH and cEH), aldehyde dehydrogenase (ALDH) and DT-diaphorase, and the phase II enzymes, gamma-glutamyltransferase (gamma-GT), glutathione transferase (GST) and uridine diphosphoglucuronyl transferase (UDPGT) were measured. Cryostat sections of tumor and surrounding liver from the same cohorts were analyzed immunohistochemically for cytochrome P450IA1 and histochemically for ALDH (benzaldehyde and hexanal), DT-diaphorase, gamma-GT and uridine diphosphoglucuronyl dehydrogenase (UDPGdH). In tumor tissues, the largest biochemical changes were found with benzaldehyde dehydrogenase, where activity increased from undetectable levels to 7.4 nmol/min/mg protein, and gamma-GT, where activity increased 12-fold over controls. Increases in other enzymes ranged from 1.26 to 2.84 times that of control liver, except EROD, which decreased, and cEH and mEH, which were unchanged. Histochemical analyses showed the induction of ALDH, gamma-GT, DT-diaphorase and UDPGdH, and the depression of cytochrome P450IA1 in hepatic neoplasms. In addition, marker enzyme histochemistry of neoplasms revealed heterogeneous populations of hepatocytes and absence of necrotic areas.

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“…In vitro studies have shown that UDPglucuronosyltransferases in fish liver possess many of the same properties as the mammalian enzymes. The activity is microsomal and is enhanced by treatment of the microsomes with detergent, digitonin or other agents which disrupt the vesicle structure (36)(37)(38)(39)(40). Trout liver UDP-glucuronosyltransferase is inducible by ,B-naphthoflavone, and there is preliminary evidence that multiple forms of the enzyme exist with different substrate selectivities (41).…”

Section: Glucuronidesmentioning

confidence: 99%

“…In the teleost fish, glucosides were found as minor metabolites (19,25) in tissue extracts, and it is not known if glucosides are excreted. Glucosidation may be a more important pathway in invertebrates (11,39,42,43), but so far insufficient data are available to draw this conclusion. Glucosides have been found in excreta of invertebrates (42).…”

Section: Glucosidationmentioning

confidence: 99%

Conjugation of organic pollutants in aquatic species.

James¹

1987

Environ Health Perspect

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Aquatic organisms can take up organic pollutants from their environment and subsequently excrete the pollutant or its biotransformation products (metabolites). Phase II (conjugation) biotransformation products are almost always less toxic than the unmetabolized organic pollutant. For many organic pollutants, the extent to which conjugates are formed is extremely important in determining the rate of excretion of the pollutant. This is because most conjugates (glycosides, sulfates, amino acid conjugates, mercapturic acids) are organic anions which are readily water-soluble and are rapidly excreted by fish (and probably higher invertebrates) by a combination of glomerular filtration and tubular transport. In this paper, each major conjugation pathway is discussed with respect to what is known about its occurrence in fish and aquatic invertebrates, both from in vivo and in vitro data. Although limited data are available, this paper also considers what is known about how each conjugation reaction affects the toxicity and potential for renal and biliary excretion of organic xenobiotic substrates.

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Glucuronidation and glucosidation reactions in aquatic species in boreal regions

Cited by 20 publications

References 0 publications

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Biochemical and histochemical properties of hepatic tumors of rainbow trout, Oncorhynchus mykiss

Conjugation of organic pollutants in aquatic species.

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