当前位置： SCI文献检索 > ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY期刊下所有文献 > Stimulation of oxyradical production of hepatic microsomes of flounder (Platichthys flesus) and perch (Perca fluviatilis) by model and pollutant xenobiotics.

Stimulation of oxyradical production of hepatic microsomes of flounder (Platichthys flesus) and perch (Perca fluviatilis) by model and pollutant xenobiotics.

Abstract：

:Stimulation of hepatic microsomal NAD(P)H-dependent hydroxyl radical (.OH) production by model compounds, viz. menadione (2-methyl-1,4-naphthoquinone) and nitrofurantoin (N-(5-nitro-2-furfurylidene)-1-aminohydantoin), and pollutant xenobiotics, viz. benzo[a]pyrene (BaP) diones (products of microsomal BaP metabolism), duroquinone (tetramethyl-1,4-benzoquinone--present in pulp mill effluent), and the pesticide lindane (gamma-hexachlorocyclohexane), was examined in flounder Platichthys flesus. Duroquinone was also studied in perch Perca fluviatilis, a freshwater species used in studies of pulp mill effluents in the aquatic environment. Microsomal .OH production was detected by the oxidation of the scavenging agent 2-keto-4-methiolbutyric acid (KMBA), using FeCl3/EDTA as a promotor of the Haber-Weiss reaction (O2- + H2O2 = .OH+OH- + O2). All xenobiotics tested, except lindane, showed synergistic interactions with ferric/EDTA indicative of redox cycling of the xenobiotic. Inhibition of menadione- and nitrofurantoin-stimulated .OH production by superoxide dismutase (50% inhibition) and catalase (80%) indicated respectively the involvement of O2- and H2O2 in .OH production. Maximal rates of KMBA oxidation (Vmax in nmol ethylene/min/mg protein) were similar for NADH and NADPH for menadione (4.58-4.61) and duroquinone (0.26-0.3 [flounder] and 0.93-0.99 [perch]), higher for NADPH than NADH for nitrofurantoin (1.21 and 0.77), and higher for NADH than NADPH for BaP diones, decreasing in the order 1,6-dione (1.12 and 0.14), 3,6-dione (0.75 and 0.25), and 6,12-dione (0.31 and 0.09). Rates for lindane, lacking a redox cycling structure, were low (0.01-0.05). Apparent Km (app. Km) values for xenobiotic were 1-2 orders of magnitude lower for BaP diones than the other compounds. App. Km was lower for NADH than NADPH for 3,6-dione (1.23 and 1.66 microM) and 6,12-dione (0.85 and 1.81 microM), but the reverse of this was found for the 1,6-dione (1.41 and 0.78 microM). App. Km values were almost identical for menadione and duroquinone and lower for NADPH (32-44 microM) than NADH (346-382 microM). The reverse was seen for nitrofurantoin, viz., 76 microM (NADH) and 269 microM (NADPH). Hepatic 1000 g supernatants of P. flesus metabolized BaP to oxyradical-generating products, moreso for beta-naphthoflavone-induced than control fish, and production was reduced by UDP-glucuronic acid for the latter but not the former. The studies indicate a widespread potential for contaminant-stimulated oxyradical generation via redox cycling and other free radical interactions of xenobiotics and their metabolites.

journal_name

Arch Environ Contam Toxicol

journal_title

Archives of environmental contamination and toxicology

authors

Lemaire P,Matthews A,Förlin L,Livingstone DR

doi

10.1007/BF00224804

subject

Has Abstract

pub_date

1994-02-01 00:00:00

pages

191-200

issue

eissn

0090-4341

issn

1432-0703

journal_volume

pub_type

杂志文章

在线工具

Stimulation of oxyradical production of hepatic microsomes of flounder (Platichthys flesus) and perch (Perca fluviatilis) by model and pollutant xenobiotics.