Vitellogenin Induction and Other Biochemical Responses in Carp, Cyprinus carpio, After Experimental Injection with 17α-Ethynylestradiol

Prespawning, adult male and female carp, Cyprinus carpio, were intraperitoneally injected with a single dose of 500 μg/kg of 17α-ethynylestradiol (EE₂). Blood samples were taken and vitellogenin levels were recorded previous to the injection and 8 days afterward. Western blot analysis of plasma VTG showed a marked response in both males (90-fold) and females (67-fold) after EE₂ injection. Also, a significant inhibition of the cytochrome P450 monooxygenase system, namely, 7-ethoxyresorufin O-deethylase (EROD) activity, as well as immunodetected CYP1A protein was observed in the EE₂-injected fish. Other cytochrome P450 isozymes, such as CYP3A or NADH cyt (b₅) reductase, did not indicate any particular trend; whereas NADPH cyt (P450) reductase was significantly induced in EE₂-injected animals. Total cytochrome P450, glutathion S-transferase (GST), and total glutathion peroxidase (GPX) fluctuated in a similar manner, but differences among treated and nontreated animals were not statistically significant. UDP glucuronyl transferase (UDPGT), similar to the antioxidant enzymes catalase, superoxide dismutase (SOD), and Se-GPX, progressively decreased in carrier and injected animals in comparison to the controls, although this trend did not reach statistical significance either. Received: 15 August 1999/Accepted: 30 November 1999     

Sediment TCDD-EQs and EROD and MROD Activities in Ranid Frogs from Agricultural and Nonagricultural Sites in Michigan (USA)

In vitro studies have demonstrated atrazine-mediated induction of 7-ethoxyresorufin O-deethylase (EROD) activity. EROD is an enzyme active in the metabolism of many compounds, including many xenobiotics. These studies have suggested that atrazine may affect reproductive function by altering steroid metabolism. The goal of this study was to determine whether relationships could be detected between measured atrazine concentrations in surface waters and the liver-somatic index (LSI) and EROD and 7-methoxyresorufin O-deethylase (MROD) activities in the livers of ranid frogs. In addition, sediment dioxin toxic equivalents (TCDD-EQs) were determined using the H4IIE-luc cell bioassay. Adult and juvenile green frogs (Rana clamitans), bullfrogs (R. catesbeiana), and Northern leopard frogs (R. pipiens) were collected from areas with extensive corn cultivation and areas where there was little agricultural activity in south central Michigan in the summer of 2003. Atrazine concentrations at nonagricultural sites ranged from less than the limit of quantification (0.17 μg atrazine/L) to 0.23 μg atrazine/L and did not exceed 1.2 μg atrazine/L at agricultural sites. Sediment TCDD-EQs were measurable only at one agricultural site. Of the measured parameters, only LSI values in adult male frogs differed significantly between agricultural and nonagricultural sites, with greater values observed at agricultural sites. In green frogs, EROD and MROD activities were measurable in both adult and juvenile frogs and were similar among sites. Median EROD activities ranged from 13 to 21 pmol/min/mg protein in adult male green frogs and from 5 to 13 pmol/min/mg protein in adult female green frogs. Juvenile frogs had greater EROD and MROD activities than adult frogs. Bullfrogs and leopard frogs had greater activities than did green frogs. Atrazine concentrations were significantly and negatively correlated with MROD activity in adult male green frogs (Spearman R = −0.800). LSI and EROD and MROD activities of adult female or juvenile green frogs were not significantly correlated with atrazine concentrations. These results suggest that atrazine does not appear to have a consistent association with EROD or MROD activities in wild-caught green frogs.     

Oxidative stress in rainbow trout (Oncorhynchus mykiss) exposed to sewage treatment plant effluent

Effluents from sewage treatment plants (STPs) can be regarded as “hot spots” of discharge releasing large amounts of chemicals into the aquatic environment. Many of these compounds are toxic to organisms due to their ability to form reactive oxygen species (ROS) and cause oxidative stress. In order to investigate if STP effluents contain compounds that may cause oxidative stress, rainbow trout (Oncorhynchus mykiss) were exposed to effluent from a Swedish STP at different dilutions in a flow-through system. Antioxidant enzymes analyzed were glutathione reductase (GR), catalase (CAT) and DT-diaphorase (DTD). Catalytic activities of CYP1A (EROD) and the conjugating enzyme glutathione-S transferase (GST) were also analyzed.Results indicate that the effluent contains prooxidants since the activities of the antioxidant enzymes GR, CAT, and DTD were all elevated after 5 days of exposure. A prolonged exposure resulted in an inhibition of DT diaphorse activity, suggesting a depleted cellular ROS defence. EROD activities increased in a dose- and time-dependent manner, which suggests the presence of aryl hydrocarbon receptor (AHR) ligands such as polycyclic aromatic hydrocarbons (PAHs) in the effluent. These results indicate that STPs do not have the capacity to biodegrade harmful chemicals sufficiently to protect the aquatic environment. However, STPs are designed to remove nutrients and not persistent pollutants from the sewage and effort should be made to diminish the amount of chemicals entering the sewage in the first place.     

The combined effects of garlic oil and fish oil on the hepatic antioxidant and drug-metabolizing enzymes of rats

This present study was designed to investigate the combined modulatory effect of garlic oil (GO) and fish oil (FO) on the antioxidant and drug metabolism systems. Rats were fed either a low-maize oil (MO) diet (50 g MO/kg), high-MO diet (235 g MO/kg) or high-FO diet (205 g FO+ 30 g MO/kg) and received different doses of GO (0-200 mg/kg body weight) three times per week for 6 weeks. Fatty acid analysis showed that 20 : 5n-3 and 22 : 6n-3 were incorporated into serum lipid at the expense of 18 : 2n-6 and 20 : 4n-6 in rats fed the high-FO diet. GO dose-dependently increased hepatic glutathione S-transferase (GST), glutathione reductase, superoxide dismutase (SOD) and ethoxyresorufin O-deethylase (EROD) activities, but decreased glutathione peroxidase and N-nitrosodimethylamine demethylase (NDMAD) activities (P<0.05). With the exception of glutathione peroxidase, the activities of glutathione reductase, SOD, GST, EROD and NDMAD were modulated by the dietary fat. The high-FO group had greater SOD and EROD activity than either MO-fed group; it also had greater NDMAD activity than the low-MO group (P<0.05). GST activity was higher in rats fed high-FO or high-MO diets than rats fed the low-MO diet. Change in erythromycin demethylase activity, however, was not caused by either dietary fat or GO. Immunoblot assay showed that GO dose-dependently enhanced the protein level of the Ya, Yb1, Yc isoenzymes of GST and cytochrome P450 (CYP) 1A1 and 3A1, but GO suppressed CYP2E1 expression. Regardless of the dosage of GO, the high-FO diet increased CYP1A1, CYP3A1 and CYP2E1 levels compared with the high- and low-MO diets. Accompanying the changes observed in immunoblots, CYP1A1 and CYP3A1 mRNA levels were increased by GO in a dose-dependent manner and also increased additively in combination with FO feeding. These present results indicate that co-administration of GO and FO modulates the antioxidant and drug-metabolizing capacity of animals and that the effect of GO and FO on drug-metabolizing enzymes is additive.     

Maternal drug abuse and human term placental xenobiotic and steroid metabolizing enzymes in vitro

We evaluated the impact of maternal drug abuse at term on human placental cytochrome P450 (CYP)-mediated (Phase I) xenobiotic and steroid-metabolizing activities [aromatase, 7-ethoxyresorufin O-deethylase (EROD), 7-ethoxycoumarin O-deethylase (ECOD), pyrene 1-hydroxylase (P1OH), and testosterone hydroxylase], and androstenedione-forming isomerase, NADPH quinone oxidoreductase (Phase II), UDP-glucuronosyltransferase (UGT), and glutathione S-transferase (GST) activities in vitro. Overall, the formation of androstenedione, P1OH, and testosterone hydroxylase was statistically significant between control and drug-abusing subjects; we observed no significant differences in any other of the phase I and II activities. In placentas from drug-abusing mothers, we found significant correlations between ECOD and P1OH activities (p < 0. 001), but not between ECOD and aromatase or P1OH and EROD activities; we also found significant correlations between blood cotinine and UGT activities (p < 0.01). In contrast, in controls (mothers who did not abuse drugs but did smoke cigarettes), the P1OH activity correlated with ECOD, EROD (p < 0.001), and testosterone hydroxylase (p < 0.001) activities. Our results (wider variation in ECOD activity among tissue from drug-abusing mothers and the significant correlation between P1OH and ECOD activities, but not with aromatase or EROD activities) indicate that maternal drug abuse results in an additive effect in enhancing placental xenobiotic metabolizing enzymes when the mother also smokes cigarettes; this may be due to enhancing a "silent" CYP form, or a new placental CYP form may be activated. The change in the steroid metabolism profile in vitro suggests that maternal drug abuse may alter normal hormonal homeostasis during pregnancy.     

Hepatic P450 Enzyme Activity, Tissue Morphology and Histology of Mink (Mustela vison) Exposed to Polychlorinated Dibenzofurans

Dose- and time-dependent effects of environmentally relevant concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQ) of 2,3,7,8-tetrachlorodibenzofuran (TCDF), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or a mixture of these two congeners on hepatic P450 enzyme activity and tissue morphology, including jaw histology, of adult ranch mink were determined under controlled conditions. Adult female ranch mink were fed either TCDF (0.98, 3.8, or 20 ng TEQ_TCDF/kg bw/day) or PeCDF (0.62, 2.2, or 9.5 ng TEQ_PeCDF/kg bw/day), or a mixture of TCDF and PeCDF (4.1 ng TEQ_TCDF/kg bw/day and 2.8 ng TEQ_PeCDF/kg bw/day, respectively) for 180 days. Doses used in this study were approximately eight times greater than those reported in a parallel field study. Activities of the cytochrome P450 1A enzymes, ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-deethylase (MROD) were significantly greater in livers of mink exposed to TCDF, PeCDF, and a mixture of the two congeners; however, there were no significant histological or morphological effects observed. It was determined that EROD and MROD activity can be used as sensitive biomarkers of exposure to PeCDF and TCDF in adult female mink; however, under the conditions of this study, the response of EROD/MROD induction occurred at doses that were less than those required to cause histological or morphological changes.     

Blarina brevicauda as a biological monitor of polychlorinated biphenyls: evaluation of hepatic cytochrome P450 induction

We assessed the value of short-tailed shrews (Blarina brevicauda) as a possible biomonitor for polychlorinated biphenyl pollution through measurement of the induction of hepatic cytochrome P450 and associated enzyme activities. First, we checked the inducibility of four monooxygenases (benzyloxyresorufin-O-dealkylase [BROD], ethoxyresorufin-O-dealkylase [EROD], methoxyresorufin-O-dealkylase [MROD], and pentoxyresorufin-O-dealkylase [PROD]) by measuring the activity of these enzymes in hepatic microsomes prepared from shrews injected with beta-naphthoflavone (betaNF) or phenobarbital (PB), typical inducers of cytochrome P4501A (CYP1A) and CYP2B enzyme families, respectively. Enzyme activity was induced in shrews that received betaNF but not in shrews that received PB; PROD was not induced by either exposure. Later, shrews were exposed to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1242:1254, in 1:2 ratio) at 0.6, 9.6, and 150 ppm in food, for 31 d. Induction in these shrews was measured by specific enzyme activity (BROD, EROD, and MROD) in hepatic microsomes, by western blotting of solubilized microsomes against antibodies to CYP1A or CYP2B, and by duration of sodium pentobarbital-induced sleep. These three CYP enzymes were induced in shrews by PCBs at similar levels of exposure as in cotton rat (Sigmodon hispidus). Neither sleep time nor the amount of CYP2B family protein were affected by PCB exposure. Blarina brevicauda can be a useful biomonitor of PCBs that induce CYP1A, especially in habitats where they are the abundant small mammal.     

Effect of Pyrene on Hepatic Cytochrome P450 1A (CYP1A) Expression in Nile Tilapia (Oreochromis niloticus)

The effect of pyrene on the regulation of the gene expression of cytochrome P4501A (CYP1A) was studied in tilapia (Oreochromis niloticus), a tropical fish of great ecological and economical importance. To evaluate CYP1A mRNA, tilapia CYP1A cDNA was cloned, sequenced, and compared with those CYP1A reported sequences in the GeneBank DNA database. The top seven matches corresponded to CYP1A from other teleosts. Hepatic CYP1A mRNA levels showed a significant increase at day 1 after pyrene injection (20 mg kg⁻¹ body weight [BW]), and this CYP1A mRNA levels did not return to basal levels for up to 5 days. The immunoblot analysis of CYP1A protein levels using polyclonal rabbit-anti-trout antibodies in the liver of pyrene-treated (20 mg kg⁻¹ BW) tilapias showed a 1.9-fold increase at day 3 after injection. Ethoxyresorufin-O-deethylase (EROD) activity increased 18-fold with respect to control fish at day 3 after injection. CYP1A protein and EROD activity remained increased for 5 days after a single pyrene IP administration. Similarly, the highest concentration of 1-hydroxypyrene (1-OH pyrene) in bile was observed in fish sacrificed at day 3 after injection. EROD activity and 1-OH pyrene concentration showed a statistically significant correlation (r = 0.85) according to the Spearman test, suggesting the participation of this cytochrome in the biotransformation of pyrene. Received: 1 July 2001/Accepted: 25 October 2001     

Effects of metals and detergents on biotransformation and detoxification enzymes of leaping mullet (Liza saliens)

In this study, feral leaping mullet (Liza saliens) liver microsomal 7-ethoxyresorufin O-deethylase (EROD), and cytosolic glutathione S-transferases (GSTs) activities were investigated using 7-ethoxyresorufin, 1-chloro-2,4-dinitrobenzene (CDNB), and ethacrynic acid (EA) as substrates, respectively. The average EROD activity was found as 1139+/-175 pmol resorufin/min/mg protein. The average GST activities towards CDNB and EA were found as 1364+/-41 and 140+/-19 nmol/min/mg protein, respectively. We have, then, investigated the in vitro effects of some metals and detergents on CYP1A and GST activities in leaping mullet liver. Leaping mullet liver microsomal EROD activity was significantly inhibited by Hg (0.1 mM), Ni (0.1 mM), Cd (0.1 mM), Cu (0.1 mM), Zn (0.1 mM), Sb (0.1 mM), Fe2+ (1 mM), Co (1 mM), Al (1 mM), and Fe3+ (1 mM), with the percent inhibition of 80, 80, 77, 75, 70, 69, 56, 53, 46, and 44, respectively. Similarly, conjugation of CDNB catalyzed by GST was inhibited significantly to lesser extend by Hg (0.1mM), Sb (0.1 mM), Cd (0.1 mM), Cu (0.1 mM), Zn (0.1 mM), Fe3+ (1 mM), Co (1 mM), and Fe2+ (1 mM), with the percent inhibition of 70, 69, 65, 61, 54, 51, 47, and 43, respectively. The degrees of inhibition observed on GST catalyzed EA conjugation by Hg (0.1 mM), Cd (0.1 mM), Sb (0.1 mM), Cu (0.1 mM), and Zn (0.1 mM) were 86, 78, 69, 51, and 42, respectively. In addition to metals, the effect of various detergents on leaping mullet liver EROD, GST-CDNB, and GST-EA activities were studied. It was found that ionic detergents strongly inhibited the EROD activity, whereas much less inhibitions were observed with GST catalyzed activities. Therefore, the CYP1A inhibition potencies of metals and detergents suggest that their contribution to the overall CYP1A induction in polycyclic aromatic hydrocarbons contaminated environmental samples has to be taken into account for better interpretation of environmental studies.     

Sediment-Quality Assessment Using the Polychaete <Emphasis Type="Italic">Arenicola marina</Emphasis>: Contamination,Bioavailability, and Toxicity

The sediment quality of Cádiz Bay, Las Palmas de Gran Canaria (LPGC) Port, Santander Bay, Algeciras Bay, and Huelva Estuary (Spain) was evaluated by analysing a battery of biochemical biomarkers―activities of biotranformation enzymes ethoxyresorufin O-deethylase [EROD], dibenzylflourescein dealkylase [DBF], and glutathione S-transferase [GST]; activity of antioxidant enzyme glutathione reductase [GR]; and lipid peroxidation [LPO]―in the polychaete Arenicola marina after laboratory sediment exposure. Huelva Estuary polychaetes showed significantly (p < 0.05) enhanced LPO, GST, and EROD activities compared with control lugworms related to metals and presumably polychlorinated biphenyls. EROD activity significant (p < 0.05) induction was associated polycyclic aromatic hydrocarbons after Santander Bay sediment exposure. Nickel appeared to significantly (p < 0.05) induce GR activity and LPO in LPGC Port sediment–exposed organisms. DBF activity significantly (p < 0.05) increased in polychaetes exposed to sediments from sewage-contaminated areas. A. marina was sensitive at the biochemical level. Integration of sediment characterization and biomarker results allowed the identification of polluted sites as well as the cause of possible sediment toxicity.     

温石棉对A549细胞细胞色素P4501A1和谷胱甘肽S转移酶活性的影响

目的：探讨温石棉对体外培养细胞中外源性化合物代谢酶活性的影响。方法：采用不同剂量的UICC温石棉（UC）和国产茫崖温石棉（MC）分别作用于A549细胞,测A549细胞中细胞色素P4501A1（CYPA1）和谷胱甘肽S转移酶（GST）活性,并用苯并（a)芘对酶活性进行诱导,再测定温石棉对2种酶诱导活性的影响。结果：UC与A549细胞作用24h,乙氧基异酚恶唑－O－去乙基酶（EROD）活性随剂量增加呈缓慢递趋势,200mg/L UC可使EROD活性升高40％,但200mg/L UC作用48h则使其活性下降32％,提示UC对A549细胞EROD活性的影响呈现低剂量短时间诱导,而高剂量长时间抑制的趋势,MC对EROD活性的影响呈现多向性,无论作用24h还是48h,25mg/L UC作用48h则使其活性下降32％,提示UC对A549细胞EROD活性的影响呈现低剂量短时间诱导,而高剂量长时间抑制的趋势,MC对EROD活性的影响呈现多向性,无论作用24h还是48h,25mg/L的MC诱导作用最强（分别为对照组的1．86和1．28倍）,但随MC剂量增大和作用时间延长,EROD活性也随之下降,最低仅为对照组的35％,UC作用对GST的影响不明显,最高仅使GST活性升高20％,MC在25mg/L时驿GST的诱导最强,为对照组的1．4倍,但随着剂量的增加,对GST活性的上诱导转为抑制,200mg/L时GST活性下降了18．7％,先用温石棉与A549细胞作用24h,再加入苯并(a)芘对酶活性进行诱导,发现无论是UC还是MC,均未对苯并(a)芘诱导的EROD活性产生明显影响。但200mg/L的UC和100mg/L的MC均可增加GST的诱导活性。结论：不同剂量温石析对EROD和GST活性表现出不同的效应,其原因可能与2种温石棉的物理化学特性及表面活性有关。     

A glucosinolate-rich extract of Japanese Daikon perturbs carcinogen-metabolizing enzyme systems in rat, being a potent inducer of hepatic glutathione S-transferase

Purpose

Glucosinolates/isothiocyanates are an established class of naturally occurring chemopreventive agents, a principal mechanism of action being to limit the generation of genotoxic metabolites of chemical carcinogens, as a result of modulation of cytochrome P450 and phase II detoxification enzymes. The objective of this study was to assess whether a glucosinolate-rich extract from Daikon sprouts, containing glucroraphasatin and glucoraphenin, is a potential chemopreventive agent by modulating such enzymes in the liver and lung of rats.

Methods

Rats were exposed to the glucosinolate-rich Daikon extract through the diet, at three dose levels, for 14 days, so that the low dose simulates dietary intake.

Results

At the low dose only, a modest increase was noted in the hepatic dealkylations of methoxy-, ethoxy-, pentoxyresorufin and benzyloxyquinoline that was accompanied by elevated expression of CYP1 and CYP3A2 apoprotein levels. In lung, only a modest increase in the dealkylation of pentoxyresorufin was observed. At higher doses, in both tissues, these increases were abolished. At the same low dietary dose, the Daikon extract elevated markedly glutathione S-transferase activity paralleled by rises in GSTα, GSTμ and GSTπ protein expression. An increase was also noted in quinone reductase activity and expression. Finally, glucuronosyl transferase and epoxide hydrolase activities and expression were also up-regulated, but necessitated higher doses.

Conclusion

Considering the ability of Daikon glucosinolates to effectively enhance detoxification enzymes, in particular glutathione S-transferase, it may be inferred that consumption of this vegetable may possess significant chemopreventive activity and warrants further evaluation through epidemiology and studies in animal models of cancer.     

Dose- and time-dependent formation of biliary benzo[a]pyrene metabolites in the marine flatfish dab (Limanda limanda)

Polycyclic aromatic hydrocarbons (PAHs) are abundant pollutants, and many PAHs are carcinogenic, but only after metabolic activation. Benzo[a]pyrene (BaP) is among the most carcinogenic PAHs. The dose and time response of two enzymes involved in BaP metabolism and the amounts of BaP metabolites excreted into the bile were evaluated in an experiment with dab (Limanda limanda). Ninety dab were exposed orally to one of five doses of BaP (0, 0.08, 0.4, 2, or 10 mg/kg) and sampled at 3, 6, or 12 d after exposure. None of the doses studied caused significant induction of either microsomal ethoxyresorufin-O-deethylase (EROD). which reflects cytochrome P450 1A (CYP1A) activity, or cytosolic glutathione-S-transferase activity (GST). Concentrations of biliary BaP metabolites significantly increased with dose and significantly decreased with time after exposure. It is concluded that biliary BaP metabolites provide a much more sensitive method than EROD (CYP1A) or GST activity to monitor recent exposure to PAHs in dab.     

Concentrations of Cadmium and Zinc in Seawater of Bohai Bay and Their Effects on Biomarker Responses in the Bivalve Chlamys farreri

Both in-field chemical investigation and in the laboratory toxic tests were carried out to systematically understand the pollution status of cadmium (Cd) and zinc (Zn) in Bohai Bay. Samples collected from surface seawater were determined to describe the distributions of Cd and Zn in Bohai Bay. The average values in our study of Cd and Zn were 0.15 μg/L and 19.68 μg/L, respectively. Both of them were lower than the first class limit of seawater quality standard in China. In the laboratory, antioxidant enzymes [SOD (Cu/Zn-SOD, Mn-SOD), CAT], lipid peroxidation (MDA), phase I and phase II enzymes (CYP4501A and GST) were investigated in the bivalves Chlamys farreri exposed to Cd and Zn at the concentration levels of Bohai Bay seawater, which were obtained from our in-field investigation. The reduced SOD, CAT, and EROD (7-ethoxyresorufin-O-deethylase) activities (with the inhibitory rate of 16.8%, 31.5%, and 51.6%, respectively) in Cd treatment were observed and resulted in obvious lipid peroxidation damage. However, treatment of Zn showed elevations in SOD and GST by 13.3% and 29.9%, respectively, and with no influence on lipid peroxidation. In summary, seawater quality in Bohai Bay seawater was ranked as good in general, but it seemed that Cd might possess a potential environmental risk by effecting pro-oxidant/antioxidant balance and phase I detoxification in C. farreri.     

Mixed Function Oxidases in an Australian Marsupial, the Brushtail Possum (Trichosurus vulpecula)

Investigation of the mixed function oxidase system of the brushtail possum was undertaken to provide fundamental information about this detoxication enzyme system in a marsupial. Brushtail possum hepatic cytochrome P450, cytochrome b ₅ and NADPH-cytochrome c reductase levels, 7-ethoxyresorufin O-deethylase and (EROD) 7-ethoxycoumarin O-deethylase (ECOD) activities were in the range of values reported for eutherian mammals. Hepatic cyrochrome P450 content was significantly greater (p < 0.01) in brushtail possums from a non-urban population in comparison to an urban population, as was ECOD activity (p < 0.0001). EROD activity was significantly greater in female brushtail possums in comparison to males (p < 0.01). The factors potentially influencing the population- and sex-specific expression of cytochrome P450 isoenzymes in the brushtail possum are discussed and include exogenous dietary xenobiotics and endogenous hormonal alterations influenced by reproductive status. Received: 15 June 1996/Revised: 1 November 1996     

Modulatory Effects of Curcumin in Conjunction with Piperine on Benzo(A)Pyrene-Mediated DNA Adducts and Biotransformation Enzymes

The antigenotoxic effects of curcumin alone and with piperine on benzo(a)pyrene-diol (BaP) epoxide DNA adducts (BaPDE-DNA adducts), and carcinogen biotransformation enzymes was investigated in liver and lung of mice. Male Swiss albino mice received curcumin (100 mgkg^?1 body weight) and piperine (20 mgkg^?1 body weight) separately as well as in combination orally in corn oil for 7 days as pretreatments and thereafter 2 h, BaP (125 mgkg^?1 body weight) was administered orally in corn oil. A single dose of BaP to normal mice increased the activities of ethoxyresorufin o-deethylase (EROD), pentoxyresorufin o-depentylase (PROD) and levels of BaPDE-DNA adducts in both the tissues. Quinone reductase (QR) activity was also elevated in the BaP-treated group in both liver and lung when compared with normal control group. Pretreatment of curcumin and curcumin plus piperine before administration of BaP significantly decreased the activities of EROD, PROD, and the level of BaPDE-DNA adducts with consequent increase in QR activities. The study clearly indicates that curcumin, when given in combination with piperine, is more effective in modulating BaPDE-DNA adducts (liver and lung), and activity of EROD (liver).     

Long-term effects of a novel phosphorothionate (RPR-II) on detoxifying enzymes in brain,lung, and kidney rats

The effects of a phosphorothionate, 2-butenoic acid-3-(diethoxyphosphinothioyl) methyl ester (RPR-II), on the activities of glutathione S-transferase (GST) and UDP-glucuronyltransferase (UDPGT) and the level of glutathione (GSH) were evaluated in rats after administration of RPR-II at 0.014 (low), 0.028 (medium), and 0.042 (high) mgkg(-1)day(-1) for 90 days and also at 28 days (withdrawal) after stopping treatment. Brain GST activity and GSH level decreased significantly at the high dose on the 45th and 90th days of treatment. Dose- and time-dependent decreases in GST activity and GSH was level were observed in lung at medium and high doses and in kidneys at all three doses on both the 45th and 90th days. UDPGT activity increased significantly in kidneys at the medium and high doses at 45 and 90 days. Brain and lung did not display any significant variations in UDPGT activity when compared with the control. Interestingly, the withdrawal study revealed that the effect was reversible within 28 days of cessation of treatment, when enzyme activity reverted to levels close to those of controls. The study revealed that RPR-II affected the GSH- and GST-dependent detoxification system of the treated tissues of rat and its potential to modulate the enzymes is in the order kidneys>lung>brain. The present subacute study suggests that RPR-II may bring about physiological upsets by altering GSH- and GST-dependent events in different tissues of exposed organisms.     

Polychlorinated Biphenyls and Biotransformation Enzymes in Three Species of Sea Turtles from the Baja California Peninsula of Mexico

Concentrations of polychlorinated biphenyls (PCBs) as well as the expression patterns of cytochrome P450 (CYP) enzymes and glutathione-S-transferase (GST) activities were measured in livers of loggerhead (Caretta caretta), green (Chelonia mydas), and olive ridley (Lepidocheyls olivacea) sea turtles from the Baja California peninsula of Mexico. The mean concentrations of total PCBs were 18.1, 10.5, and 15.2 ng/g wet weight (ww) respectively for the three species and PCB 153 was the dominant congener in all samples. Total PCB concentrations were dominated by penta- and hexa-chlorinated biphenyls. The mean estimated TEQs were 42.8, 22.9, and 10.4 pg/g (ww) for loggerhead, green, and olive ridley, respectively, and more than 70% was accounted for by non-ortho PCBs. Western blots revealed the presence of hepatic microsomal proteins that cross-reacted with anti-CYP2K1 and anti-CYP3A27 antibodies but not with anti-CYP1A antibody. There were no significant differences in GST activities between species. Grouping congeners based on structure–activity relationships for CYP isoenzymes suggested limited activity of CYP1A contribution to PCB biotransformation in sea turtles. These results suggest potential accumulation of PCBs that are CYP1A substrates and provide evidence for biotransformation capacity, which differs from known animal models, highlighting the need for further studies in reptiles, particularly those threatened with extinction.     

苯并[a]芘诱导内皮细胞细胞色素P4501A1表达的研究

目的：探讨苯并[a]芘(BaP)诱导猪主动脉内皮细胞细胞色素P4501A1(CYP1A1)表达及活性的影响。方法：离体培养猪主动脉内皮细胞，不同浓度BaP(0、0．5、1．0、5．0、10．0μmol／L)染毒24h，分别以Western-blot法和免疫组化方法检测不同浓度BaP诱导内皮细胞合成CYP1A1的影响，同时还探讨了乙氧基异吩噁唑-o-去乙氧基酶(EROD)活力的变化规律。结果：Western-blot法未能检测出对照组CYP1A1的表达，而各染毒组均检出了CYP1A1的表达；免疫组化结果显示染毒组仅在部分内皮细胞呈阳性反应；EROD活力诱导高峰的BaP浓度为0．5～1.0μmol／L。结论：BaP可诱导部分猪主动脉内皮细胞合成CYP1A1；EROD活力诱导高峰的BaP浓度为0．5～1．0μmol／L。