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Sample records for inhibit acetaminophen glucuronidation

  1. Organochlorines inhibit acetaminophen glucuronidation by redirecting UDP-glucuronic acid towards the D-glucuronate pathway

    SciTech Connect

    Chan, Tom S. Wilson, John X.; Selliah, Subajini; Bilodeau, Marc; Zwingmann, Claudia; Poon, Raymond; O'Brien, Peter J.

    2008-11-01

    Industry-derived organochlorines are persistent environmental pollutants that are a continuing health concern. The effects of these compounds on drug metabolism are not well understood. In the current study we present evidence that the inhibition of acetaminophen (APAP) glucuronidation by minute concentrations of organochlorines correlates well with their ability to stimulate the D-glucuronate pathway leading to ascorbate synthesis. A set of 6 arylated organochlorines, including 5 PCB (polychlorinated biphenyl) congeners, were assessed for their effects on APAP glucuronidation in isolated hepatocytes from male Sprague-Dawley rats. The capacity of each organochlorine to inhibit APAP glucuronidation was found to be directly proportional to its capacity to stimulate ascorbate synthesis. PCB153, PCB28 and bis-(4-chlorophenyl sulfone) (BCPS) in increasing order were the most effective organochlorines for inhibiting APAP glucuronidation and stimulating the D-glucuronate pathway. None of the 3 inhibitors of APAP glucuronidation were able to alter the expression of UGT1A6, UGT1A7 and UGT1A8 (the major isoforms responsible for APAP glucuronidation in the rat), however, their efficacy at inhibiting APAP glucuronidation was proportional to their capacity to deplete UDP-glucuronic acid (UDPGA). BCPS-mediated inhibition of APAP glucuronidation in isolated hepatocytes had non-competitive characteristics and was insensitive to the inactivation of cytochrome P450. The effective organochlorines were also able to selectively stimulate the hydrolysis of UDPGA to UDP and glucuronate in isolated microsomes, but could not inhibit APAP glucuronidation in microsomes when UDPGA was in excess. We conclude that organochlorines are able to inhibit APAP glucuronidation in hepatocytes by depleting UDPGA via redirecting UDPGA towards the D-glucuronate pathway. Because the inhibition is non-competitive, low concentrations of these compounds could have long term inhibitory effects on the

  2. Glucuronidation in the chimpanzee (Pan troglodytes): studies with acetaminophen, oestradiol and morphine.

    PubMed

    Wong, H; Grace, J E; Wright, M R; Browning, M R; Grossman, S J; Bai, S A; Christ, D D

    2006-12-01

    The chimpanzee has recently been characterized as a surrogate for oxidative drug metabolism in humans and as a pharmacokinetic model for the selection of drug candidates. In the current study, the glucuronidation of acetaminophen, morphine and oestradiol was evaluated in the chimpanzee to extend the characterization of this important animal model. Following oral administration of acetaminophen (600 mg) to chimpanzees (n=2), pharmacokinetics were comparable with previously reported human values, namely mean oral clearance 0.91 vs. 0.62+/-0.05 l h-1 kg-1, apparent volume of distribution 2.29 vs. 1.65+/-0.25 l kg-1, and half-life 1.86 vs. 1.89+/-7h, for chimpanzee vs. human, respectively. Urinary excretions (percentage of dose) of acetaminophen, acetaminophen glucuronide and acetaminophen sulfate were also similar between chimpanzees and humans, namely 2.3 vs. 5.0, 63.1 vs. 54.7, and 25.0 vs. 32.3%, respectively. Acetaminophen, oestradiol and morphine glucuronide formation kinetics were investigated using chimpanzee (n=2) and pooled human liver microsomes (n=10). V(max) (app) and K(m)(app) (or S(50)(app)) for acetaminophen glucuronide, morphine 3- and 6-glucuronide, and oestradiol 3- and 17-glucuronide formation were comparable in both species. Eadie-Hofstee plots of oestradiol 3-glucuronide formation in chimpanzee microsomes were characteristic of autoactivation kinetics. Western immunoblot analysis of chimpanzee liver microsomes revealed a single immunoreactive band when probed with anti-human UGT1A1, anti-human UGT1A6, and anti-human UGT2B7. Taken collectively, these data demonstrate similar glucuronidation characteristics in chimpanzees and humans.

  3. Characterization of niflumic acid as a selective inhibitor of human liver microsomal UDP-glucuronosyltransferase 1A9: application to the reaction phenotyping of acetaminophen glucuronidation.

    PubMed

    Miners, John O; Bowalgaha, Kushari; Elliot, David J; Baranczewski, Pawel; Knights, Kathleen M

    2011-04-01

    Enzyme selective inhibitors represent the most valuable experimental tool for reaction phenotyping. However, only a limited number of UDP-glucuronosyltransferase (UGT) enzyme-selective inhibitors have been identified to date. This study characterized the UGT enzyme selectivity of niflumic acid (NFA). It was demonstrated that 2.5 μM NFA is a highly selective inhibitor of recombinant and human liver microsomal UGT1A9 activity. Higher NFA concentrations (50-100 μM) inhibited UGT1A1 and UGT2B15 but had little effect on the activities of UGT1A3, UGT1A4, UGT1A6, UGT2B4, UGT2B7, and UGT2B17. NFA inhibited 4-methylumbelliferone and propofol (PRO) glucuronidation by recombinant UGT1A9 and PRO glucuronidation by human liver microsomes (HLM) according to a mixed (competitive-noncompetitive) mechanism, with K(i) values ranging from 0.10 to 0.40 μM. Likewise, NFA was a mixed or noncompetitive inhibitor of recombinant and human liver microsomal UGT1A1 (K(i) range 14-18 μM), whereas competitive inhibition (K(i) 62 μM) was observed with UGT2B15. NFA was subsequently applied to the reaction phenotyping of human liver microsomal acetaminophen (APAP) glucuronidation. Consistent with previous reports, APAP was glucuronidated by recombinant UGT1A1, UGT1A6, UGT1A9, and UGT2B15. NFA concentrations in the range of 2.5 to 100 μM inhibited APAP glucuronidation by UGT1A1, UGT1A9, and UGT2B15 but not by UGT1A6. The mean V(max) for APAP glucuronidation by HLM was reduced by 20, 35, and 40%, respectively, in the presence of 2.5, 50, and 100 μM NFA. Mean K(m) values decreased in parallel with V(max), although the magnitude of the decrease was smaller. Taken together, the NFA inhibition data suggest that UGT1A6 is the major enzyme involved in APAP glucuronidation.

  4. Acetaminophen

    MedlinePlus

    Backprin® (as a combination product containing Acetaminophen, Caffeine, Magnesium Salicylate) ... Forte® (as a combination product containing Acetaminophen, Caffeine, Magnesium Salicylate, Phenyltoloxamine)

  5. Diethylstilbestrol can effectively accelerate estradiol-17-O-glucuronidation, while potently inhibiting estradiol-3-O-glucuronidation

    SciTech Connect

    Zhu, Liangliang; Xiao, Ling; Xia, Yangliu; Zhou, Kun; Wang, Huili; Huang, Minyi; Ge, Guangbo; Wu, Yan; Wu, Ganlin; Yang, Ling

    2015-03-01

    This in vitro study investigates the effects of diethylstilbestrol (DES), a widely used toxic synthetic estrogen, on estradiol-3- and 17-O- (E2-3/17-O) glucuronidation, via culturing human liver microsomes (HLMs) or recombinant UDP-glucuronosyltransferases (UGTs) with DES and E2. DES can potently inhibit E2-3-O-glucuronidation in HLM, a probe reaction for UGT1A1. Kinetic assays indicate that the inhibition follows a competitive inhibition mechanism, with the Ki value of 2.1 ± 0.3 μM, which is less than the possible in vivo level. In contrast to the inhibition on E2-3-O-glucuronidation, the acceleration is observed on E2-17-O-glucuronidation in HLM, in which cholestatic E2-17-O-glucuronide is generated. In the presence of DES (0–6.25 μM), K{sub m} values for E2-17-O-glucuronidation are located in the range of 7.2–7.4 μM, while V{sub max} values range from 0.38 to 1.54 nmol/min/mg. The mechanism behind the activation in HLM is further demonstrated by the fact that DES can efficiently elevate the activity of UGT1A4 in catalyzing E2-17-O-glucuronidation. The presence of DES (2 μM) can elevate V{sub max} from 0.016 to 0.81 nmol/min/mg, while lifting K{sub m} in a much lesser extent from 4.4 to 11 μM. Activation of E2-17-O-glucuronidation is well described by a two binding site model, with K{sub A}, α, and β values of 0.077 ± 0.18 μM, 3.3 ± 1.1 and 104 ± 56, respectively. However, diverse effects of DES towards E2-3/17-O-glucuronidation are not observed in liver microsomes from several common experimental animals. In summary, this study issues new potential toxic mechanisms for DES: potently inhibiting the activity of UGT1A1 and powerfully accelerating the formation of cholestatic E2-17-O-glucuronide by UGT1A4. - Highlights: • E2-3-O-glucuronidation in HLM is inhibited when co-incubated with DES. • E2-17-O-glucuronidation in HLM is stimulated when co-incubated with DES. • Acceleration of E2-17-O-glucuronidationin in HLM by DES is via activating the

  6. Mutual Regioselective Inhibition of Human UGT1A1-Mediated Glucuronidation of Four Flavonoids

    PubMed Central

    Ma, Guo; Wu, Baojian; Gao, Song; Yang, Zhen; Ma, Yong; Hu, Ming

    2013-01-01

    UDP-glucuronosyltransferase (UGT) 1A1-catalyzed glucuronidation is an important elimination pathway of flavonoids, and mutually inhibitory interactions may occur when two or more flavonoids are co-administered. Our recent research suggested that glucuronidation of flavonoids displayed distinct positional preferences, but whether this will lead to the mutually regioselective inhibition of UGT1A1-mediated glucuronidation of flavonoids is unknown. Therefore, we chose three monohydroxyflavone isomers 3-hydroxyflavone (3HF), 7-hydroxyflavone (7HF), 4′-hydroxyflavone (4′HF) and one trihydroxyflavone 3,7,4′-trihydroxyflavone (3,7,4′THF) as the model compounds to characterize the possible mutually regioselective inhibition of glucuronidation using expressed human UGT1A1. Apparent kinetic parameters [e.g., reaction velocity (V), Michaelis-Menten constant (Km), maximum rate of metabolism (Vmax), concentration at which inhibitor achieve 50% inhibition or IC50] and the Lineweaver-Burk plots were used to evaluate the apparent kinetic mechanisms of inhibition of glucuronidation. The results showed that UGT1A1-mediated glucuronidation of three monohydroxyflavones (i.e., 3HF, 7HF and 4′HF) and 3,7,4′THF was mutually inhibitory, and the mechanisms of inhibition appeared to be the mixed-typed inhibition. Specifically, the inhibitory effects displayed certain positional preference. Glucuronidation of 3HF was more easily inhibited by 3,7,4′THF than that of 7HF or 4′HF. Compared to 7-O-glucuronidation of 3,7,4′THF, 3-O-glucuronidation of 3,7,4′THF was more inhibited by 3HF and 4′HF, whereas glucuronidation at both 3-OH and 7-OH positions of 3,7,4′THF was more easily inhibited by 7HF than by 3HF and 4′HF. In conclusion, 3HF, 7HF, 4′HF and 3,7,4′THF were both substrates and inhibitors of UGT1A1, and they exhibited mutually regioselective inhibition of UGT1A1-mediated glucuronidation via a mixed-type inhibitory mechanism. PMID:23786524

  7. Decrease of plasma and urinary oxidative metabolites of acetaminophen after consumption of watercress by human volunteers.

    PubMed

    Chen, L; Mohr, S N; Yang, C S

    1996-12-01

    To investigate the effect of the consumption of watercress (Nasturtium officinale R. Br.), a cruciferous vegetable, on acetaminophen metabolism, the pharmacokinetics of acetaminophen and its metabolites were studied in a crossover trial of human volunteers. A single oral dose of acetaminophen (1 gm) was given 10 hours after ingestion of watercress homogenates (50 gm). In comparison with acetaminophen only, the ingestion of watercress resulted in a significant reduction in the area under the plasma cysteine acetaminophen (Cys-acetaminophen) concentration-time curve and in the peak plasma Cys-acetaminophen concentration by 28% +/- 3% and by 21% +/- 4% (mean +/- SE; n = 7; p < 0.005), respectively. Correspondingly, the Cys-acetaminophen formation rate constant and Cys-acetaminophen formation fraction were decreased by 55% +/- 9% and 52% +/- 7% (p < 0.01), respectively. Consistent with the results obtained from the plasma, the total urinary excretion of Cys-acetaminophen in 24 hours was also reduced. A decrease of mercapturate acetaminophen, a Cys-acetaminophen metabolite, was also shown in the plasma and urine samples. However, the plasma pharmacokinetic processes and the urinary excretions of acetaminophen, acetaminophen glucuronide, and acetaminophen sulfate were not altered significantly by the watercress treatment. These results suggest that the consumption of watercress causes a decrease in the levels of oxidative metabolites of acetaminophen, probably due to inhibition of oxidative metabolism of this drug.

  8. Acetaminophen hepatotoxicity: studies on the mechanism of cysteamine protection

    SciTech Connect

    Miller, M.G.; Jollow, D.J.

    1986-03-30

    Inhibition of the cytochrome P-450-dependent formation of the acetaminophen-reactive metabolite was investigated as a possible mechanism for cysteamine protection against acetaminophen hepatotoxicity. Studies in isolated hamster hepatocytes indicated that cysteamine competitively inhibited the cytochrome P-450 enzyme system as represented by formation of the acetaminophen-glutathione conjugate. However, cysteamine was not a potent inhibitor of glutathione conjugate formation (Ki = 1.17 mM). Cysteamine also weakly inhibited the glucuronidation of acetaminophen (Ki = 2.44 mM). In vivo studies were in agreement with the results obtained in isolated hepatocytes; cysteamine moderately inhibited both glucuronidation and the cytochrome P-450-dependent formation of acetaminophen mercapturate. The overall elimination rate constant (beta) for acetaminophen was correspondingly decreased. Since cysteamine decreased both beta and the apparent rate constant for mercapturate formation (K'MA), the proportion of the dose of acetaminophen which is converted to the toxic metabolite (K'MA/beta) was not significantly decreased in the presence of cysteamine. Apparently, cysteamine does inhibit the cytochrome P-450-dependent formation of the acetaminophen-reactive metabolite, but this effect is not sufficient to explain antidotal protection.

  9. Cryptotanshinone and dihydrotanshinone I exhibit strong inhibition towards human liver microsome (HLM)-catalyzed propofol glucuronidation.

    PubMed

    Cong, Ming; Hu, Cui-Min; Cao, Yun-Feng; Fang, Zhong-Ze; Tang, Shu-Hong; Wang, Jia-Rui; Luo, Jun-Sheng

    2013-03-01

    Danshen is one of the most famous herbs in the world, and more and more danshen-prescribed drugs interactions have been reported in recent years. Evaluation of inhibition potential of danshen's major ingredients towards UDP-glucuronosyltransferases (UGTs) will be helpful for understanding detailed mechanisms for danshen-drugs interaction. Therefore, the aim of the present study is to investigate the inhibitory situation of cryptotanshinone and dihydrotanshinone I towards UGT enzyme-catalyzed propofol glucuronidation. In vitro the human liver microsome (HLM) incubation system was used, and the results showed that cryptotanshinone and dihydrotanshinone I exhibited dose-dependent inhibition towards HLM-catalyzed propofol glucuronidation. Dixon plot and Lineweaver-Burk plot showed that the inhibition type was best fit to competitive inhibition type for both cryptotanshinone and dihydrotanshinone I. The second plot using the slopes from the Lineweaver-Burk plot versus the concentrations of cryptotanshinone or dihydrotanshinone I was employed to calculate the inhibition parameters (Ki) to be 0.4 and 1.7μM, respectively. Using the reported maximum plasma concentration (Cmax), the altered in vivo exposure of propofol increased by 10% and 8.2% for the co-administration of dihydrotanshinone I and cryptotanshinone, respectively. All these results indicated the possible danshen-propofol interaction due to the inhibition of dihydrotanshinone I and cryptotanshinone towards the glucuronidation reaction of propofol.

  10. Acetaminophen and meloxicam inhibit platelet aggregation and coagulation in blood samples from humans.

    PubMed

    Martini, Angela K; Rodriguez, Cassandra M; Cap, Andrew P; Martini, Wenjun Z; Dubick, Michael A

    2014-12-01

    Acetaminophen (Ace) and meloxicam (Mel) are the two types of analgesic and antipyretic medications. This study investigated the dose responses of acetaminophen and meloxicam on platelet aggregation and coagulation function in human blood samples. Blood samples were collected from six healthy humans and processed to make platelet-adjusted (100 × 10 cells/μl) blood samples. Acetaminophen (Tylenol, Q-PAP, 100 mg/ml) was added at the doses of 0 μg/ml (control), 214 μg/ml (the standard dose, 1 ×), 4 ×, 8 ×, 10 ×, 12 ×, 16 ×, and 20 ×. Similarly, meloxicam (Metacam, 5 mg/ml) was added at doses of 0 μg/ml (control), 2.85 μg/ml (the standard dose, 1 ×), 4 ×, 8 ×, 10 ×, 12 ×, 16 ×, and 20 ×. Fifteen minutes after the addition of acetaminophen and/or meloxicam, platelet aggregation was stimulated with collagen (2 μg/ml) or arachidonic acid (0.5 mmol/l) and assessed using a Chrono-Log 700 aggregometer. Coagulation function was assessed by prothrombin time (PT), activated partial thromboplastin time (aPTT), and using Rotem thrombelastogram. A robust inhibition by acetaminophen and/or meloxicam was observed in arachidonic acid-stimulated platelet aggregation starting at 1 × dose. Collagen-stimulated platelet aggregation was inhibited by ACE starting at 1 × (78 ± 10% of control), and by meloxicam starting at 4 × (72 ± 5% of control, both P < 0.05). The inhibitions by acetaminophen and meloxicam combined were similar to those by acetaminophen or meloxicam. aPTT was prolonged by meloxicam starting at 4 ×. No changes were observed in PT or any of Rotem measurements by acetaminophen and/or meloxicam. Acetaminophen and meloxicam compromised platelet aggregation and aPTT. Further effort is warranted to characterize the effects of acetaminophen and meloxicam on bleeding in vivo.

  11. BGP-15 inhibits caspase-independent programmed cell death in acetaminophen-induced liver injury

    SciTech Connect

    Nagy, Gabor; Szarka, Andras; Lotz, Gabor; Doczi, Judit; Wunderlich, Livius; Kiss, Andras; Jemnitz, Katalin; Veres, Zsuzsa; Banhegyi, Gabor; Schaff, Zsuzsa; Suemegi, Balazs; Mandl, Jozsef

    2010-02-15

    It has been recently shown that acute acetaminophen toxicity results in endoplasmic reticulum redox stress and an increase in cells with apoptotic phenotype in liver. Since activation of effector caspases was absent, the relevance of caspase-independent mechanisms in acetaminophen-induced programmed cell death was investigated. BGP-15, a drug with known protective actions in conditions involving redox imbalance, has been co-administered with a single sublethal dose of acetaminophen. Proapoptotic events and outcome of the injury were investigated. ER redox alterations and early ER-stress-related signaling events induced by acetaminophen, such as ER glutathione depletion, phosphorylation of eIF2alpha and JNK and induction of the transcription factor GADD153, were not counteracted by co-treatment with BGP-15. However, BGP-15 prevented AIF mitochondria-to-nucleus translocation and mitochondrial depolarization. BGP-15 co-treatment attenuated the rate of acetaminophen-induced cell death as assessed by apoptotic index and enzyme serum release. These results reaffirm that acute acetaminophen toxicity involves oxidative stress-induced caspase-independent cell death. In addition, pharmacological inhibition of AIF translocation may effectively protect against or at least delay acetaminophen-induced programmed cell death.

  12. In vitro inhibitory effects of non-steroidal anti-inflammatory drugs on 4-methylumbelliferone glucuronidation in recombinant human UDP-glucuronosyltransferase 1A9--potent inhibition by niflumic acid.

    PubMed

    Mano, Yuji; Usui, Takashi; Kamimura, Hidetaka

    2006-01-01

    The inhibitory potencies of non-steroidal anti-inflammatory drugs (NSAIDs) on UDP-glucuronosyltransferase (UGT) 1A9 activity were investigated in recombinant human UGT1A9 using 4-methylumbelliferone (4-MU) as a substrate for glucuronidation. 4-MU glucuronidation (4-MUG) showed Michaelis-Menten kinetics with a Km value of 6.7 microM. The inhibitory effects of the following seven NSAIDs were investigated: acetaminophen, diclofenac, diflunisal, indomethacin, ketoprofen, naproxen and niflumic acid. Niflumic acid had the most potent inhibitory effect on 4-MUG with an IC50 value of 0.0341 microM. The IC50 values of diflunisal, diclofenac and indomethacin were 1.31, 24.2, and 34.1 microM, respectively, while acetaminophen, ketoprofen and naproxen showed less potent inhibition. Niflumic acid, diflunisal, diclofenac and indomethacin inhibited 4-MUG competitively with Ki values of 0.0275, 0.710, 53.3 and 69.9 microM, respectively, being similar to each IC50 value. In conclusion, of the seven NSAIDs investigated, niflumic acid was the most potent inhibitor of recombinant UGT1A9 via 4-MUG in a competitive manner.

  13. Glucuronide transport across the endoplasmic reticulum membrane is inhibited by epigallocatechin gallate and other green tea polyphenols.

    PubMed

    Révész, Katalin; Tütto, Anna; Margittai, Eva; Bánhegyi, Gábor; Magyar, Judit E; Mandl, József; Csala, Miklós

    2007-01-01

    Toxic endogenous or exogenous compounds can be inactivated by various conjugation reactions. Glucuronidation (i.e. conjugation with glucuronate) is especially important due to the large number of drugs and chemical carcinogens that are detoxified through this pathway. Stable and harmless glucuronides can be reactivated by enzymatic hydrolysis thus inhibitors of glucuronidase activity reduce the risk of chemical carcinogenesis. The aim of this study was to reveal whether this mechanism contributes to the anti-cancer effect of green tea flavanols, which has been shown in various animal models. Therefore, we investigated the effect of these polyphenols on deglucuronidation in rat liver microsomes and in Hepa 1c1c7 mouse hepatoma cells, using 4-methylumbelliferyl glucuronide as model substrate. Tea flavanols inhibited beta-glucuronidase in intact vesicles, where glucuronide transport across the microsomal membrane is rate-limiting, but were almost ineffective in permeabilized vesicles. Epigallocatechin gallate, the major green tea flavanol was shown to have a concentration-dependent inhibitory effect on both beta-glucuronidase activity and glucuronide transport in native vesicles. Epigallocatechin gallate also inhibited beta-glucuronidase activity in native Hepa 1c1c7 mouse hepatoma cells, while failed to affect the enzyme in alamethicin-permeabilized cells, where the endoplasmic membrane barrier was eliminated. Our findings indicate that tea flavanols inhibit deglucuronidation in the endoplasmic reticulum at the glucuronide transport stage. This phenomenon might potentially contribute to the cancer-preventing dietary or pharmacological effect attributed to these catechins.

  14. Studies to further investigate the inhibition of human liver microsomal CYP2C8 by the acyl-β-glucuronide of gemfibrozil.

    PubMed

    Jenkins, S M; Zvyaga, T; Johnson, S R; Hurley, J; Wagner, A; Burrell, R; Turley, W; Leet, J E; Philip, T; Rodrigues, A D

    2011-12-01

    In previous studies, gemfibrozil acyl-β-glucuronide, but not gemfibrozil, was found to be a mechanism-based inhibitor of cytochrome P450 2C8. To better understand whether this inhibition is specific for gemfibrozil acyl-β-glucuronide or whether other glucuronide conjugates are potential substrates for inhibition of this enzyme, we evaluated several pharmaceutical compounds (as their acyl glucuronides) as direct-acting and metabolism-dependent inhibitors of CYP2C8 in human liver microsomes. Of 11 compounds that were evaluated as their acyl glucuronide conjugates, only gemfibrozil acyl-β-glucuronide exhibited mechanism-based inhibition, indicating that CYP2C8 mechanism-based inhibition is very specific to certain glucuronide conjugates. Structural analogs of gemfibrozil were synthesized, and their glucuronide conjugates were prepared to further examine the mechanism of inhibition. When the aromatic methyl groups on the gemfibrozil moiety were substituted with trifluoromethyls, the resulting glucuronide conjugate was a weaker inhibitor of CYP2C8 and mechanism-based inhibition was abolished. However, the glucuronide conjugates of monomethyl gemfibrozil analogs were mechanism-based inhibitors of CYP2C8, although not as potent as gemfibrozil acyl-β-glucuronide itself. The ortho-monomethyl analog was a more potent inhibitor than the meta-monomethyl analog, indicating that CYP2C8 favors the ortho position for oxidation and potential inhibition. Molecular modeling of gemfibrozil acyl-β-glucuronide in the CYP2C8 active site is consistent with the ortho-methyl position being the favored site of covalent attachment to the heme. Moreover, hydrogen bonding to four residues (Ser100, Ser103, Gln214, and Asn217) is implicated.

  15. Inhibition of human alcohol and aldehyde dehydrogenases by acetaminophen: Assessment of the effects on first-pass metabolism of ethanol.

    PubMed

    Lee, Yung-Pin; Liao, Jian-Tong; Cheng, Ya-Wen; Wu, Ting-Lun; Lee, Shou-Lun; Liu, Jong-Kang; Yin, Shih-Jiun

    2013-11-01

    Acetaminophen is one of the most widely used over-the-counter analgesic, antipyretic medications. Use of acetaminophen and alcohol are commonly associated. Previous studies showed that acetaminophen might affect bioavailability of ethanol by inhibiting gastric alcohol dehydrogenase (ADH). However, potential inhibitions by acetaminophen of first-pass metabolism (FPM) of ethanol, catalyzed by the human ADH family and by relevant aldehyde dehydrogenase (ALDH) isozymes, remain undefined. ADH and ALDH both exhibit racially distinct allozymes and tissue-specific distribution of isozymes, and are principal enzymes responsible for ethanol metabolism in humans. In this study, we investigated acetaminophen inhibition of ethanol oxidation with recombinant human ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, ADH1C2, ADH2, and ADH4, and inhibition of acetaldehyde oxidation with recombinant human ALDH1A1 and ALDH2. The investigations were done at near physiological pH 7.5 and with a cytoplasmic coenzyme concentration of 0.5 mM NAD(+). Acetaminophen acted as a noncompetitive inhibitor for ADH enzymes, with the slope inhibition constants (Kis) ranging from 0.90 mM (ADH2) to 20 mM (ADH1A), and the intercept inhibition constants (Kii) ranging from 1.4 mM (ADH1C allozymes) to 19 mM (ADH1A). Acetaminophen exhibited noncompetitive inhibition for ALDH2 (Kis = 3.0 mM and Kii = 2.2 mM), but competitive inhibition for ALDH1A1 (Kis = 0.96 mM). The metabolic interactions between acetaminophen and ethanol/acetaldehyde were assessed by computer simulation using inhibition equations and the determined kinetic constants. At therapeutic to subtoxic plasma levels of acetaminophen (i.e., 0.2-0.5 mM) and physiologically relevant concentrations of ethanol (10 mM) and acetaldehyde (10 μm) in target tissues, acetaminophen could inhibit ADH1C allozymes (12-26%) and ADH2 (14-28%) in the liver and small intestine, ADH4 (15-31%) in the stomach, and ALDH1A1 (16-33%) and ALDH2 (8.3-19%) in all 3 tissues. The

  16. Inhibition of glucuronidation and oxidative metabolism of buprenorphine using GRAS compounds or dietary constituents/supplements: in vitro proof of concept.

    PubMed

    Maharao, Neha V; Joshi, Anand A; Gerk, Phillip M

    2017-03-01

    The present study investigated the potential of generally recognized as safe (GRAS) compounds or dietary substances to inhibit the presystemic metabolism of buprenorphine and to increase its oral bioavailability. Using IVIVE, buprenorphine extraction ratios in intestine and liver were predicted as 96% and 71%, respectively. In addition, the relative fraction of buprenorphine metabolized by oxidation and glucuronidation in these two organs was estimated using pooled human intestinal and liver microsomes. In both organs, oxidation appeared to be the major metabolic pathway with a 6 and 4 fold higher intrinsic clearance than glucuronidation in intestine and liver, respectively. The oral bioavailability of buprenorphine was predicted to be 1.16%. Inhibition of 75% and 50% of intestinal and hepatic presystemic metabolism would result in an Foral of 49%, which is comparable to the bioavailability of sublingual buprenorphine. In human liver microsomes, chrysin, curcumin, ginger extract, hesperitin, magnolol, quercetin and silybin inhibited ≥50% glucuronidation, whereas chrysin, curcumin, ginger extract, 6-gingerol, pterostilbene, resveratrol and silybin exhibited ≥30% inhibition of oxidation. In human intestinal microsomes, curcumin, ginger extract, α-mangostin, quercetin and silybin inhibited ≥50% glucuronidation while chrysin, ginger extract, α-mangostin, pterostilbene and resveratrol exhibited ≥30% inhibition of oxidation. These results demonstrate the feasibility of our proposed approach of using GRAS or dietary compounds to inhibit the presystemic metabolism of buprenorphine and thus improve its oral bioavailability. An oral buprenorphine formulation containing these inhibitors or their combinations has promising potential to replace sublingual buprenorphine. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Milk Thistle Constituents Inhibit Raloxifene Intestinal Glucuronidation: A Potential Clinically Relevant Natural Product-Drug Interaction.

    PubMed

    Gufford, Brandon T; Chen, Gang; Vergara, Ana G; Lazarus, Philip; Oberlies, Nicholas H; Paine, Mary F

    2015-09-01

    Women at high risk of developing breast cancer are prescribed selective estrogen response modulators, including raloxifene, as chemoprevention. Patients often seek complementary and alternative treatment modalities, including herbal products, to supplement prescribed medications. Milk thistle preparations, including silibinin and silymarin, are top-selling herbal products that may be consumed by women taking raloxifene, which undergoes extensive first-pass glucuronidation in the intestine. Key constituents in milk thistle, flavonolignans, were previously shown to be potent inhibitors of intestinal UDP-glucuronosyl transferases (UGTs), with IC50s ≤ 10 μM. Taken together, milk thistle preparations may perpetrate unwanted interactions with raloxifene. The objective of this work was to evaluate the inhibitory effects of individual milk thistle constituents on the intestinal glucuronidation of raloxifene using human intestinal microsomes and human embryonic kidney cell lysates overexpressing UGT1A1, UGT1A8, and UGT1A10, isoforms highly expressed in the intestine that are critical to raloxifene clearance. The flavonolignans silybin A and silybin B were potent inhibitors of both raloxifene 4'- and 6-glucuronidation in all enzyme systems. The Kis (human intestinal microsomes, 27-66 µM; UGT1A1, 3.2-8.3 µM; UGT1A8, 19-73 µM; and UGT1A10, 65-120 µM) encompassed reported intestinal tissue concentrations (20-310 µM), prompting prediction of clinical interaction risk using a mechanistic static model. Silibinin and silymarin were predicted to increase raloxifene systemic exposure by 4- to 5-fold, indicating high interaction risk that merits further evaluation. This systematic investigation of the potential interaction between a widely used herbal product and chemopreventive agent underscores the importance of understanding natural product-drug interactions in the context of cancer prevention.

  18. Morphine glucuronidation and glucosidation represent complementary metabolic pathways that are both catalyzed by UDP-glucuronosyltransferase 2B7: kinetic, inhibition, and molecular modeling studies.

    PubMed

    Chau, Nuy; Elliot, David J; Lewis, Benjamin C; Burns, Kushari; Johnston, Martin R; Mackenzie, Peter I; Miners, John O

    2014-04-01

    Morphine 3-β-D-glucuronide (M3G) and morphine 6-β-D-glucuronide (M6G) are the major metabolites of morphine in humans. More recently, morphine-3-β-d-glucoside (M-3-glucoside) was identified in the urine of patients treated with morphine. Kinetic and inhibition studies using human liver microsomes (HLM) and recombinant UGTs as enzyme sources along with molecular modeling were used here to characterize the relationship between morphine glucuronidation and glucosidation. The M3G to M6G intrinsic clearance (C(Lint)) ratio (∼5.5) from HLM supplemented with UDP-glucuronic acid (UDP-GlcUA) alone was consistent with the relative formation of these metabolites in humans. The mean C(Lint) values observed for M-3-glucoside by incubations of HLM with UDP-glucose (UDP-Glc) as cofactor were approximately twice those for M6G formation. However, although the M3G-to-M6G C(Lint) ratio remained close to 5.5 when human liver microsomal kinetic studies were performed in the presence of a 1:1 mixture of cofactors, the mean C(Lint) value for M-3-glucoside formation was less than that of M6G. Studies with UGT enzyme-selective inhibitors and recombinant UGT enzymes, along with effects of BSA on morphine glycosidation kinetics, were consistent with a major role of UGT2B7 in both morphine glucuronidation and glucosidation. Molecular modeling identified key amino acids involved in the binding of UDP-GlcUA and UDP-Glc to UGT2B7. Mutagenesis of these residues abolished morphine glucuronidation and glucosidation. Overall, the data indicate that morphine glucuronidation and glucosidation occur as complementary metabolic pathways catalyzed by a common enzyme (UGT2B7). Glucuronidation is the dominant metabolic pathway because the binding affinity of UDP-GlcUA to UGT2B7 is higher than that of UDP-Glc.

  19. Anti-cytochrome P450 IIE1 (anti IIE1) and dimethyl sulfoxide inhibit acetaminophen and dimethylnitrosamine oxidation similarly

    SciTech Connect

    Jaw, S.; Jeffery, E.H. ); Roberts, D.W. )

    1991-03-11

    To evaluate specificity of dimethyl sulfoxide (DMSO), the authors compared anti IIE1 and DMSO inhibition of P450 oxidations. Hepatic microsomes from control and acetone-induced female Swiss-Webster mice were preincubated with polyclonal anti IIE1 or IgG for 20 min at 4C before addition of an NADPH-generating system, DMSO or buffer, and substrate (Ethylmorphine, EM; dimethylnitrosamine, DMN; or acetaminophen, AP; 1 mM final concentration). After 20 min at 37C, the incubations were terminated by adding 20% trichloroacetic acid or methanol. Formaldehyde was determined by the Nash method when using EM or DMN as substrate. AP-glutathione conjugate was determined by HPLC when using AP as substrate. Anti IIE1 and DMSO did not inhibit EM demethylation in control or acetone microsomes. However, DMSO inhibited DMN demethylation by 26% and 64% in control and 30% and 75% in acetone microsomes. Anti IIE1 inhibited DMN demethylation by 44% and 24% in control and acetone microsomes, respectively. DMSO inhibited AP metabolism by 31% and 56% and anti IIE1 inhibited AP metabolism by 33%, in control microsomes. The inhibitions of DMN and AP metabolism by anti IIE1 and DMSO were only additive at submaximal inhibitor concentrations and confirm that DMSO specifically inhibits IIE1 activity.

  20. Acetaminophen and Meloxicam Inhibit Platelet Aggregation and Coagulation in Blood Samples from Humans

    DTIC Science & Technology

    2014-01-01

    participant was sampled once with a total of 100-ml blood volume. Exclusion criteria included pregnancy, on- going therapeutic anticoagulation , and use...of thromboxane A2 (TxA2) from prostaglandin H2, which is generated from arachidonic acid by cyclo-oxygenase (COX-1). The antiplatelet effects of...is acetaminophen? Some practical cautions with this widely used agent . Clin Pediatr (Phila) 1973; 12:692– 696. 3 Whyte IM, Buckley NA, Reith DM

  1. A randomized, controlled study on the influence of acetaminophen, diclofenac, or naproxen on aspirin-induced inhibition of platelet aggregation.

    PubMed

    Galliard-Grigioni, Katja S; Reinhart, Walter H

    2009-05-01

    Nonsteroidal anti-inflammatory drugs (NSAID) may interfere with aspirin (acetylsalicylic acid) and increase the risk for cardiovascular events. The clinical relevance is uncertain. The aim of this study was to analyse the influence of a co-administration of aspirin and NSAID on platelet aggregation. In a randomized, placebo controlled trial, eleven healthy volunteers were studied during 4 separate study periods of 4 days each. Individuals were treated on each occasion with 100 mg aspirin daily in combination with either 3 x 1 g acetaminophen, 3 x 50 mg diclofenac, 3 x 250 mg naproxen, or 3 x 1 placebo. Primary hemostasis was assessed with a platelet function analyser (PFA-100), which measures the closure time (CT) of a collagen- and epinephrine-coated pore by aggregating platelets in flowing blood. Naproxen enhanced the anti-aggregatory action of aspirin after 24 h (CT rising from 104+/-16 s at baseline to 212+/-69 s at 24 h, P<0.001), which was not seen with any other drug combination. Diclofenac reduced the anti-aggregatory action of aspirin in the first two days, since the CT did not rise significantly (109+/-19 s, 148+/-56 s, and 168+/-66 s at 0 h, 24 h, 48 h, respectively, P>0.05). Acetaminophen had no effect compared with placebo. After 4 days of treatment platelet aggregation was similarly inhibited by all combinations. We conclude that a co-administration of NSAID and aspirin may interfere with platelet inhibition at the beginning of a treatment with an increase of naproxen and a decrease of diclofenac. This effect is lost after 4 days, suggesting that a regular daily co-administration of NSAID does not have an influence on platelet inhibition by aspirin.

  2. The acetaminophen-derived bioactive N-acylphenolamine AM404 inhibits NFAT by targeting nuclear regulatory events.

    PubMed

    Caballero, Francisco J; Navarrete, Carmen M; Hess, Sandra; Fiebich, Bernd L; Appendino, Giovanni; Macho, Antonio; Muñoz, Eduardo; Sancho, Rocío

    2007-04-01

    AM404 is a synthetic TRPV1/CB(1) hybrid ligand with inhibitory activity on the anandamide transporter and is used for the pharmacological manipulation of the endocannabinoid system. It has been recently described that acetaminophen is metabolised in the brain to form the bioactive N-acylphenolamine AM404 and therefore, we have evaluated the effect of this metabolite in human T cells, discovering that AM404 is a potent inhibitor of TCR-mediated T-cell activation. Moreover, we found that AM404 specifically inhibited both IL-2 and TNF-alpha gene transcription and TNF-alpha synthesis in CD3/CD28-stimulated Jurkat T cells in a FAAH independent way. To further characterize the biochemical inhibitory mechanisms of AM404, we examined the signaling pathways that regulate the activation of the transcription factors NF-kappaB, NFAT and AP-1 in Jurkat cells. We found that AM404 inhibited both the binding to DNA and the transcriptional activity of endogenous NFAT and the transcriptional activity driven by the over expressed fusion protein Gal4-NFAT (1-415). However, AM404 did not affect early steps in NFAT signaling such as CD3-induced calcium mobilization and NFAT1 dephosphorylation. The NFAT inhibitory activity of AM404 seems to be quite specific since this compound did not interfere with the signaling pathways leading to AP-1 or NF-kappaB activation. These findings provide new mechanistic insights into the immunological effects of AM404 which in part could explain some of the activities ascribed to the widely used acetaminophen.

  3. Biochemical changes associated with the potentiation of acetaminophen hepatotoxicity by brief anesthesia with diethyl ether.

    PubMed

    To, E C; Wells, P G

    1986-12-01

    Acetaminophen hepatotoxicity in male CD-1 mice was enhanced markedly by brief anesthesia with diethyl ether (ether), and particularly so if acetaminophen was given several hours after ether. The present study was conducted to examine the possible biochemical mechanisms behind this delayed toxicologic synergism. In vitro biochemical studies indicated that ether anesthesia produced a delayed reduction in the activities of glucuronyl transferase and glutathione (GSH) S-transferase, and in the hepatic content of GSH. The hepatic content but not activity of the cytochromes P-450 was initially reduced by ether but recovered by the time of maximal toxicologic enhancement. In vivo studies showed that ether produced a small decrease in the plasma concentrations of glucuronide and sulfate conjugates of acetaminophen, with a concomitant, minor increase in the half-life of acetaminophen, and a major increase in the bioactivation of acetaminophen, as determined by an early, 2-fold increase in the plasma GSH and cysteine conjugates of acetaminophen, and a 3-fold increase in the covalent binding of acetaminophen to hepatocellular protein. Decreases produced by ether in the in vivo production of acetaminophen glucuronide correlated with increasing plasma concentrations of unmetabolised acetaminophen, decreasing hepatic GSH content and increasing covalent binding of acetaminophen to hepatocellular protein when these measurements were performed in the same animals. The biochemical mechanisms underlying the potentiation of acetaminophen hepatoxicity as measured by plasma glutamic pyruvic transaminase concentrations appeared to be due to delayed, complex effects of ether upon multiple enzymatic pathways of acetaminophen elimination and detoxification.

  4. Gabapentin Inhibits Protein Kinase C Epsilon Translocation in Cultured Sensory Neurons with Additive Effects When Coapplied with Paracetamol (Acetaminophen)

    PubMed Central

    2017-01-01

    Gabapentin is a well-established anticonvulsant drug which is also effective for the treatment of neuropathic pain. Although the exact mechanism leading to relief of allodynia and hyperalgesia caused by neuropathy is not known, the blocking effect of gabapentin on voltage-dependent calcium channels has been proposed to be involved. In order to further evaluate its analgesic mechanisms, we tested the efficacy of gabapentin on protein kinase C epsilon (PKCε) translocation in cultured peripheral neurons isolated from rat dorsal root ganglia (DRGs). We found that gabapentin significantly reduced PKCε translocation induced by the pronociceptive peptides bradykinin and prokineticin 2, involved in both inflammatory and chronic pain. We recently showed that paracetamol (acetaminophen), a very commonly used analgesic drug, also produces inhibition of PKCε. We tested the effect of the combined use of paracetamol and gabapentin, and we found that the inhibition of translocation adds up. Our study provides a novel mechanism of action for gabapentin in sensory neurons and suggests a mechanism of action for the combined use of paracetamol and gabapentin, which has recently been shown to be effective, with a cumulative behavior, in the control of postoperative pain in human patients. PMID:28299349

  5. Gabapentin Inhibits Protein Kinase C Epsilon Translocation in Cultured Sensory Neurons with Additive Effects When Coapplied with Paracetamol (Acetaminophen).

    PubMed

    Vellani, Vittorio; Giacomoni, Chiara

    2017-01-01

    Gabapentin is a well-established anticonvulsant drug which is also effective for the treatment of neuropathic pain. Although the exact mechanism leading to relief of allodynia and hyperalgesia caused by neuropathy is not known, the blocking effect of gabapentin on voltage-dependent calcium channels has been proposed to be involved. In order to further evaluate its analgesic mechanisms, we tested the efficacy of gabapentin on protein kinase C epsilon (PKCε) translocation in cultured peripheral neurons isolated from rat dorsal root ganglia (DRGs). We found that gabapentin significantly reduced PKCε translocation induced by the pronociceptive peptides bradykinin and prokineticin 2, involved in both inflammatory and chronic pain. We recently showed that paracetamol (acetaminophen), a very commonly used analgesic drug, also produces inhibition of PKCε. We tested the effect of the combined use of paracetamol and gabapentin, and we found that the inhibition of translocation adds up. Our study provides a novel mechanism of action for gabapentin in sensory neurons and suggests a mechanism of action for the combined use of paracetamol and gabapentin, which has recently been shown to be effective, with a cumulative behavior, in the control of postoperative pain in human patients.

  6. Schisandrol B protects against acetaminophen-induced hepatotoxicity by inhibition of CYP-mediated bioactivation and regulation of liver regeneration.

    PubMed

    Jiang, Yiming; Fan, Xiaomei; Wang, Ying; Chen, Pan; Zeng, Hang; Tan, Huasen; Gonzalez, Frank J; Huang, Min; Bi, Huichang

    2015-01-01

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Schisandra sphenanthera is a traditional hepato-protective Chinese medicine and Schisandrol B (SolB) is one of its major active constituents. In this study, the protective effect of SolB against APAP-induced acute hepatotoxicity in mice and the involved mechanisms were investigated. Morphological and biochemical assessments clearly demonstrated a protective effect of SolB against APAP-induced liver injury. SolB pretreatment significantly attenuated the increases in alanine aminotransferase and aspartate aminotransferase activity, and prevented elevated hepatic malondialdehyde formation and the depletion of mitochondrial glutathione (GSH) in a dose-dependent manner. SolB also dramatically altered APAP metabolic activation by inhibiting the activities of CYP2E1 and CYP3A11, which was evidenced by significant inhibition of the formation of the oxidized APAP metabolite NAPQI-GSH. A molecular docking model also predicted that SolB had potential to interact with the CYP2E1 and CYP3A4 active sites. In addition, SolB abrogated APAP-induced activation of p53 and p21, and increased expression of liver regeneration and antiapoptotic-related proteins such as cyclin D1 (CCND1), PCNA, and BCL-2. This study demonstrated that SolB exhibited a significant protective effect toward APAP-induced liver injury, potentially through inhibition of CYP-mediated APAP bioactivation and regulation of the p53, p21, CCND1, PCNA, and BCL-2 to promote liver regeneration.

  7. Schisandrol B Protects Against Acetaminophen-Induced Hepatotoxicity by Inhibition of CYP-Mediated Bioactivation and Regulation of Liver Regeneration

    PubMed Central

    Jiang, Yiming; Fan, Xiaomei; Wang, Ying; Chen, Pan; Zeng, Hang; Tan, Huasen; Gonzalez, Frank J.; Bi, Huichang

    2015-01-01

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Schisandra sphenanthera is a traditional hepato-protective Chinese medicine and Schisandrol B (SolB) is one of its major active constituents. In this study, the protective effect of SolB against APAP-induced acute hepatotoxicity in mice and the involved mechanisms were investigated. Morphological and biochemical assessments clearly demonstrated a protective effect of SolB against APAP-induced liver injury. SolB pretreatment significantly attenuated the increases in alanine aminotransferase and aspartate aminotransferase activity, and prevented elevated hepatic malondialdehyde formation and the depletion of mitochondrial glutathione (GSH) in a dose-dependent manner. SolB also dramatically altered APAP metabolic activation by inhibiting the activities of CYP2E1 and CYP3A11, which was evidenced by significant inhibition of the formation of the oxidized APAP metabolite NAPQI–GSH. A molecular docking model also predicted that SolB had potential to interact with the CYP2E1 and CYP3A4 active sites. In addition, SolB abrogated APAP-induced activation of p53 and p21, and increased expression of liver regeneration and antiapoptotic-related proteins such as cyclin D1 (CCND1), PCNA, and BCL-2. This study demonstrated that SolB exhibited a significant protective effect toward APAP-induced liver injury, potentially through inhibition of CYP-mediated APAP bioactivation and regulation of the p53, p21, CCND1, PCNA, and BCL-2 to promote liver regeneration. PMID:25319358

  8. Bazhen Decoction Protects against Acetaminophen Induced Acute Liver Injury by Inhibiting Oxidative Stress, Inflammation and Apoptosis in Mice

    PubMed Central

    Song, Erqun; Fu, Juanli; Xia, Xiaomin; Su, Chuanyang; Song, Yang

    2014-01-01

    Bazhen decoction is a widely used traditional Chinese medicinal decoction, but the scientific validation of its therapeutic potential is lacking. The objective of this study was to investigate corresponding anti-oxidative, anti-inflammatory and anti-apoptosis activities of Bazhen decoction, using acetaminophen-treated mice as a model system. A total of 48 mice were divided into four groups. Group I, negative control, treated with vehicle only. Group II, fed with 500 mg/kg/day Bazhen decoction for 10 continuous days. Group III, received a single dose of 900 mg/kg acetaminophen. Group IV, fed with 500 mg/kg/day Bazhen decoction for 10 continuous days and a single dose of 900 mg/kg acetaminophen 30 min before last Bazhen decoction administration. Bazhen decoction administration significantly decrease acetaminophen-induced serum ALT, AST, ALP, LDH, TNF-α, IL-1β, ROS, TBARS and protein carbonyl group levels, as well as GSH depletion and loss of MMP. Bazhen decoction restore SOD, CAT, GR and GPx activities and depress the expression of pro-inflammatory factors, such as iNOS, COX-2, TNF-α, NF-κB, IL-1β and IL-6, respectively. Moreover, Bazhen decoction down-regulate acetaminophen-induced Bax/Bcl-2 ratio, caspase 3, caspase 8 and caspase 9. These results suggest the anti-oxidative, anti-inflammatory and anti-apoptosis properties of Bazhen decoction towards acetaminophen-induced liver injury in mice. PMID:25222049

  9. Iso-glucuronides.

    PubMed

    Dickinson, Ronald G

    2011-03-01

    This review on isomers or acyl glucuronides (iso-glucuronides) updates earlier reviews, and attempts to place in context the advances that have been made, especially over the last 15 years. The essential chemistry behind the intramolecular acyl migration and anomerization reactions of acyl glucuronides has been appreciated for 30 years. The great advances in the past 15 years have been in understanding the dynamics and kinetics of these processes in vitro, using highly sophisticated modern technology, e.g. LC-NMR, LC-MS/MS. In this way, earlier assumptions on kinetics and identification of migration isomers and anomers have come under intense review and update. Extensive structure-activity relationships, involving electronic and steric characteristics of an acyl glucuronide and its possible 7 isomers (excluding transient open-chain species) have been delineated. The covalent modification of endogenous proteins and other macromolecules has been further explored, though direct linkage between such modification and toxic sequelae remains elusive. An alternative view of acyl glucuronides and iso-glucuronides as just xenobiotics has perhaps added the dimension that acyl glucuronidation (and attendant formation of iso-glucuronides) does not necessarily mean that glucuronidation of the aglycone has ended metabolic sequences in vivo.

  10. Disposition of acetaminophen at 4, 6, and 8 g/day for 3 days in healthy young adults.

    PubMed

    Gelotte, C K; Auiler, J F; Lynch, J M; Temple, A R; Slattery, J T

    2007-06-01

    The objective of this study was to determine the disposition and tolerability of 1, 1.5, and 2 g acetaminophen every 6 h for 3 days. Group I healthy adults received acetaminophen (4 then 6 g/day) or placebo; Group II received acetaminophen (4 then 8 g/day) or placebo. Acetaminophen and metabolites were measured in plasma and urine. Hepatic aminotransferases were measured daily. At steady state, acetaminophen concentrations were surprisingly lower than predicted from single-dose data, although sulfate formation clearance (fCL) was lower as expected, indicating cofactor depletion with possible sulfotransferase saturation. In contrast, glucuronide fCL was unexpectedly higher, strongly suggesting glucuronosyltransferase induction. This is the first evidence that acetaminophen induces its own glucuronidation. No dose-dependent differences were detected in fCL of thiol metabolites formed via cytochrome P4502E1. Hepatic aminotransferases stayed within reference ranges, and the incidence and frequency of adverse events were similar for acetaminophen and placebo. Although dose-dependence of acetaminophen disposition was reported previously, this study shows a novel finding of time-dependent disposition during repeated dosing. Unexpected increases in glucuronide fCL more than offset decreases in sulfate fCL, thus increasing acetaminophen clearance overall. Thiol metabolite fCL remained constant up to 8 g/day. These findings have important implications in short-term (3 day) tolerability of supratherapeutic acetaminophen doses in healthy adults.

  11. Acetaminophen and aspirin inhibit superoxide anion generation and lipid peroxidation, and protect against 1-methyl-4-phenyl pyridinium-induced dopaminergic neurotoxicity in rats.

    PubMed

    Maharaj, D S; Saravanan, K S; Maharaj, H; Mohanakumar, K P; Daya, S

    2004-04-01

    We assessed the antioxidant activity of non-narcotic analgesics, acetaminophen and aspirin in rat brain homogenates and neuroprotective effects in vivo in rats intranigrally treated with 1-methyl-4-phenyl pyridinium (MPP+). Both drugs inhibited cyanide-induced superoxide anion generation, as well as lipid peroxidation in rat brain homogenates, the combination of the agents resulting in a potentiation of this effect. Acetaminophen or aspirin when administered alone or in combination, did not alter dopamine (DA) levels in the forebrain or in the striatum. Intranigral infusion of MPP+ in rats caused severe depletion of striatal DA levels in the ipsilateral striatum in rats by the third day. Systemic post-treatment of acetaminophen afforded partial protection, whereas similar treatment of aspirin resulted in complete blockade of MPP+-induced striatal DA depletion. While these findings suggest usefulness of non-narcotic analgesics in neuroprotective therapy in neurodegenerative diseases, aspirin appears to be a potential candidate in prophylactic as well as in adjuvant therapy in Parkinson's disease.

  12. Acetaminophen overdose

    MedlinePlus

    ... measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. Blood tests will be done to check how much acetaminophen is in the blood. The person may receive: Activated charcoal Airway support, including oxygen, breathing tube through the ...

  13. Chitosan and blueberry treatment induces arginase activity and inhibits nitric oxide production during acetaminophen-induced hepatotoxicity

    PubMed Central

    Ozcelik, Eda; Uslu, Sema; Burukoglu, Dilek; Musmul, Ahmet

    2014-01-01

    Background: Liver diseases have become a major problem of the worldwide. More than 50% of all cases of liver failure can be attributed to drugs. Among these, acetaminophen is the most common cause. Objective: The aim of this study was to investigate the the hepatoprotective effects of blueberry and chitosan on tissue arginase activity, ornithine and nitric oxide levels during the acetaminophen-induced hepatotoxicity. Materials and Methods: Acetaminophen (250 mg/kg body weight per day), blueberry (60 mg/kg body weight per day) and, chitosan (200 mg/kg body weight per day) were administered to the rats by oral gavage during the experimental period. Results: Blueberry and chitosan significantly decreased liver arginase activity and ornithine levelsand and increased nitric oxide levels. Glutathione levels were remarkably increased by chitosan and blueberry treatments. Conclusion: The results of the present study indicate that blueberry and chitosan effectively protected against the acetaminophen-induced hepatotoxicity. The hepatoprotective effect afforded by blueberry and chitosan can be attributed to its antioxidant and anti-inflammatory activities. PMID:24991095

  14. Exacerbation of acetaminophen hepatotoxicity by the anthelmentic drug fenbendazole.

    PubMed

    Gardner, Carol R; Mishin, Vladimir; Laskin, Jeffrey D; Laskin, Debra L

    2012-02-01

    Fenbendazole is a broad-spectrum anthelmintic drug widely used to prevent or treat nematode infections in laboratory rodent colonies. Potential interactions between fenbendazole and hepatotoxicants such as acetaminophen are unknown, and this was investigated in this study. Mice were fed a control diet or a diet containing fenbendazole (8-12 mg/kg/day) for 7 days prior to treatment with acetaminophen (300 mg/kg) or phosphate buffered saline. In mice fed a control diet, acetaminophen administration resulted in centrilobular hepatic necrosis and increases in serum transaminases, which were evident within 12 h. Acetaminophen-induced hepatotoxicity was markedly increased in mice fed the fenbendazole-containing diet, as measured histologically and by significant increases in serum transaminase levels. Moreover, in mice fed the fenbendazole-containing diet, but not the control diet, 63% mortality was observed within 24 h of acetaminophen administration. Fenbendazole by itself had no effect on liver histology or serum transaminases. To determine if exaggerated hepatotoxicity was due to alterations in acetaminophen metabolism, we analyzed sera for the presence of free acetaminophen and acetaminophen-glucuronide. We found that there were no differences in acetaminophen turnover. We also measured cytochrome P450 (cyp) 2e1, cyp3a, and cyp1a2 activity. Whereas fenbendazole had no effect on the activity of cyp2e1 or cyp3a, cyp1a2 was suppressed. A prolonged suppression of hepatic glutathione (GSH) was also observed in acetaminophen-treated mice fed the fenbendazole-containing diet when compared with the control diet. These data demonstrate that fenbendazole exacerbates the hepatotoxicity of acetaminophen, an effect that is related to persistent GSH depletion. These findings are novel and suggest a potential drug-drug interaction that should be considered in experimental protocols evaluating mechanisms of hepatotoxicity in rodent colonies treated with fenbendazole.

  15. Inhibition of P-Glycoprotein and Multidrug Resistance-Associated Protein 2 Regulates the Hepatobiliary Excretion and Plasma Exposure of Thienorphine and Its Glucuronide Conjugate

    PubMed Central

    Kong, Ling-Lei; Shen, Guo-Lin; Wang, Zhi-Yuan; Zhuang, Xiao-Mei; Xiao, Wei-Bin; Yuan, Mei; Gong, Ze-Hui; Li, Hua

    2016-01-01

    Thienorphine (TNP) is a novel partial opioid agonist that has completed phase II clinical evaluation as a promising drug candidate for the treatment of opioid dependence. Previous studies have shown that TNP and its glucuronide conjugate (TNP-G) undergo significant bile excretion. The purpose of this study was to investigate the roles of efflux transporters in regulating biliary excretion and plasma exposure of TNP and TNP-G. An ATPase assay suggested that TNP and TNP-G were substrates of P-gp and MRP2, respectively. The in vitro data from rat hepatocytes showed that bile excretion of TNP and TNP-G was regulated by the P-gp and MRP2 modulators. The accumulation of TNP and TNP-G in HepG2 cells significantly increased by the treatment of mdr1a or MRP2 siRNA for P-gp or MRP2 modulation. In intact rats, the bile excretion, and pharmacokinetic profiles of TNP and TNP-G were remarkably changed with tariquidar and probenecid pretreatment, respectively. Tariquidar increased the Cmax and AUC0-t and decreased MRT and T1/2 of TNP, whereas probenecid decreased the plasma exposure of TNP-G and increased its T1/2. Knockdown P-gp and MRP2 function using siRNA significantly increased the plasma exposure of TNP and TNP-G and reduced their mean retention time in mice. These results indicated the important roles of P-gp and MRP2 in hepatobiliary excretion and plasma exposure of TNP and TNP-G. Inhibition of the efflux transporters may affect the pharmacokinetics of TNP and result in a drug-drug interaction between TNP and the concomitant transporter inhibitor or inducer in clinic. PMID:27555820

  16. How to Safely Give Acetaminophen

    MedlinePlus

    ... to 2-Year-Old How to Safely Give Acetaminophen KidsHealth > For Parents > How to Safely Give Acetaminophen ... without getting a doctor's OK first. What Is Acetaminophen Also Called? Acetaminophen is the generic name of ...

  17. Flavonoid glucuronides from Helicteres isora.

    PubMed

    Kamiya, K; Saiki, Y; Hama, T; Fujimoto, Y; Endang, H; Umar, M; Satake, T

    2001-05-01

    Five flavonoid glucuronides were obtained from the fruit of Helicteres isora, three of which were previously unknown compounds: isoscutellarein 4'-methyl ether 8-O-beta-D-glucuronide 6"-n-butyl ester. isoscutellarein 4'-methyl ether 8-O-beta-D-glucuronide 2", 4"-disulfate and isoscutellarein 8-O-beta-D-glucuronide 2",4"-disulfate. The structures were determined on the basis of spectroscopy and hydrolysis experiments.

  18. Species difference in the inhibitory potentials of non-steroidal anti-inflammatory drugs on the hepatic sulfation and glucuronidation of bioactive flavonoids: differential observations among common inhibition parameters.

    PubMed

    Fong, Sophia Yui Kau; Zuo, Zhong

    2014-05-01

    1. This study elucidated the species differences between rats and humans in the inhibitory potential of drugs against sulfation and glucuronidation, and whether such differences depend on the inhibition parameter adopted. 2. With 14 non-steroidal anti-inflammatory drugs (NSAIDs) as model inhibitors and three flavanoids baicalein, wogonin and oroxylin A as model substrates, three common inhibition parameters percentage of control, IC50 and Ki were determined in rat liver cytosols (RLCs), human liver cytosols (HLCs), rat liver microsomes (RLMs) and human liver microsomes (HLMs). The closeness of the inhibition parameters from rat liver preparations to that from human liver preparations was analyzed by geometric mean fold error (GMFE) and statistical comparisons. 3. The percentage of control in RLC/RLM was not significantly different from that in HLC/HLM, with a GMFE of 0.85 (RLC-HLC) and 1.03 (RLM-HLM); whereas the IC50 and Ki in RLC/RLM were significantly different from that in HLC/HLM. The trend of difference was consistent between IC50 and Ki, where these parameters in RLC and RLM underestimated (GMFE <0.5) and overestimated (GMFE >2) that in HLC and HLM, respectively. 4. In conclusion, the inhibitory potentials of NSAIDs against sulfation and glucuronidation in rats and humans were different and depended on the adopted inhibition parameters.

  19. The acetaminophen metabolite N-acetyl-p-benzoquinone imine (NAPQI) inhibits glutathione synthetase in vitro; a clue to the mechanism of 5-oxoprolinuric acidosis?

    PubMed

    Walker, Valerie; Mills, Graham A; Anderson, Mary E; Ingle, Brandall L; Jackson, John M; Moss, Charlotte L; Sharrod-Cole, Hayley; Skipp, Paul J

    2017-02-01

    1. Metabolic acidosis due to accumulation of l-5-oxoproline is a rare, poorly understood, disorder associated with acetaminophen treatment in malnourished patients with chronic morbidity. l-5-Oxoprolinuria signals abnormal functioning of the γ-glutamyl cycle, which recycles and synthesises glutathione. Inhibition of glutathione synthetase (GS) by N-acetyl-p-benzoquinone imine (NAPQI) could contribute to 5-oxoprolinuric acidosis in such patients. We investigated the interaction of NAPQI with GS in vitro. 2. Peptide mapping of co-incubated NAPQI and GS using mass spectrometry demonstrated binding of NAPQI with cysteine-422 of GS, which is known to be essential for GS activity. Computational docking shows that NAPQI is properly positioned for covalent bonding with cysteine-422 via Michael addition and hence supports adduct formation. 3. Co-incubation of 0.77 μM of GS with NAPQI (25-400 μM) decreased enzyme activity by 16-89%. Inhibition correlated strongly with the concentration of NAPQI and was irreversible. 4. NAPQI binds covalently to GS causing irreversible enzyme inhibition in vitro. This is an important novel biochemical observation. It is the first indication that NAPQI may inhibit glutathione synthesis, which is pivotal in NAPQI detoxification. Further studies are required to investigate its biological significance and its role in 5-oxoprolinuric acidosis.

  20. Acetaminophen dosing for children

    MedlinePlus

    Tylenol ... Acetaminophen is used to help: Reduce aches, pain, sore throat, and fever in children with a cold ... Children's acetaminophen can be taken as liquid or chewable tablet. If your child is under 2 years old, check ...

  1. Lycopene inhibits reactive oxygen species production in SK-Hep-1 cells and attenuates acetaminophen-induced liver injury in C57BL/6 mice.

    PubMed

    Bandeira, Ana Carla Balthar; da Silva, Talita Prato; de Araujo, Glaucy Rodrigues; Araujo, Carolina Morais; da Silva, Rafaella Cecília; Lima, Wanderson Geraldo; Bezerra, Frank Silva; Costa, Daniela Caldeira

    2017-02-01

    Our aim was to investigate the antioxidant potential of lycopene in different experimental liver models: in vitro, to evaluate the influence of lycopene on reactive oxygen species (ROS) production mediated by the PKC pathway and in vivo, to evaluate the protective effects of lycopene in an experimental model of hepatotoxicity. The in vitro study assessed the lycopene antioxidant potential by the quantification of ROS production in SK-Hep-1 cells unstimulated or stimulated by an activator of the PKC pathway. The role of NADPH oxidase was evaluated by measuring its inhibition potential using an inhibitor of this enzyme. In the in vivo study, male C57BL/6 mice received lycopene (10 or 100 mg/kg by oral gavage) and 1 h later, acetaminophen (APAP) (500 mg/kg) was administrated. Lycopene decreased ROS production in SK-Hep-1 cells through inhibition of NADPH oxidase, brought about in the PKC pathway. Lycopene improved hepatotoxicity acting as an antioxidant, reduced GSSG and regulated tGSH and CAT levels, reduced oxidative damage primarily by decreasing protein carbonylation, promoted the downregulation of MMP-2 and reduced areas of necrosis improving the general appearance of the lesion in C57BL/6 mice. Lycopene is a natural compound that was able to inhibit the production of ROS in vitro and mitigate the damage caused by APAP overdose in vivo.

  2. Curative Effects of Thiacremonone against Acetaminophen-Induced Acute Hepatic Failure via Inhibition of Proinflammatory Cytokines Production and Infiltration of Cytotoxic Immune Cells and Kupffer Cells

    PubMed Central

    Kim, Yu Ri; Ban, Jung Ok; Yoo, Hwan Soo; Lee, Yong Moon; Yoon, Yeo Pyo; Eum, So Young; Jeong, Heon Sang; Yoon, Do-young; Han, Sang Bae; Hong, Jin Tae

    2013-01-01

    High doses of acetaminophen (APAP; N-acetyl-p-aminophenol) cause severe hepatotoxicity after metabolic activation by cytochrome P450 2E1. This study was undertaken to examine the preventive effects of thiacremonone, a compound extracted from garlic, on APAP-induced acute hepatic failure in male C57BL/6J. Mice received with 500 mg/kg APAP after a 7-day pretreatment with thiacremonone (10–50 mg/kg). Thiacremonone inhibited the APAP-induced serum ALT and AST levels in a dose-dependent manner, and markedly reduced the restricted area of necrosis and inflammation by administration of APAP. Thiacremonone also inhibited the APAP-induced depletion of intracellular GSH, induction of nitric oxide, and lipid peroxidation as well as expression of P450 2E1. After APAP injection, the numbers of Kupffer cells, natural killer cells, and cytotoxic T cells were elevated, but the elevated cell numbers in the liver were reduced in thiacremonone pretreated mice. The expression levels of I-309, M-CSF, MIG, MIP-1α, MIP-1β, IL-7, and IL-17 were increased by APAP treatment, which were inhibited in thiacremonone pretreated mice. These data indicate that thiacremonone could be a useful agent for the treatment of drug-induced hepatic failure and that the reduction of cytotoxic immune cells as well as proinflammatory cytokine production may be critical for the prevention of APAP-induced acute liver toxicity. PMID:23935693

  3. Leflunomide or A77 1726 protect from acetaminophen-induced cell injury through inhibition of JNK-mediated mitochondrial permeability transition in immortalized human hepatocytes

    SciTech Connect

    Latchoumycandane, Calivarathan; Seah, Quee Ming; Tan, Rachel C.H.; Sattabongkot, Jetsumon; Beerheide, Walter; Boelsterli, Urs A. . E-mail: phcbua@nus.edu.sg

    2006-11-15

    Leflunomide, a disease-modifying anti-rheumatic drug, protects against T-cell-mediated liver injury by poorly understood mechanisms. The active metabolite of leflunomide, A77 1726 (teriflunomide) has been shown to inhibit stress-activated protein kinases (JNK pathway), which are key regulators of mitochondria-mediated cell death. Therefore, we hypothesized that leflunomide may protect from drugs that induce the mitochondrial permeability transition (mPT) by blocking the JNK signaling pathway. To this end, we exposed cultured immortalized human hepatocytes (HC-04) to the standard protoxicant drug acetaminophen (APAP), which induces CsA-sensitive mPT-mediated cell death. We determined the effects of leflunomide on the extent of APAP-induced hepatocyte injury and the upstream JNK-mediated mitochondrial signaling pathways. We found that leflunomide or A77 1726 concentration-dependently protected hepatocytes from APAP (1 mM)-induced mitochondrial permeabilization and lethal cell injury. This was not due to proximal inhibition of CYP-catalyzed APAP bioactivation to its thiol-reactive metabolite. Instead, we demonstrate that leflunomide (20 {mu}M) inhibited the APAP-induced early (3 h) activation (phosphorylation) of JNK1/2, thus inhibiting phosphorylation of the anti-apoptotic protein Bcl-2 and preventing P-Bcl-2-mediated induction of the mPT. This greatly attenuated mitochondrial cytochrome c release, which we used as a marker for mitochondrial permeabilization. The specific JNK2 inhibitor SP600125 similarly protected from APAP-induced cell death. In conclusion, these findings are consistent with our hypothesis that leflunomide protects from protoxicant-induced hepatocyte injury by inhibiting JNK signaling and preventing mPT induction.

  4. Saikosaponin d protects against acetaminophen-induced hepatotoxicity by inhibiting NFκB and STAT3 signaling

    PubMed Central

    Liu, Aiming; Tanaka, Naoki; Sun, Lu; Guo, Bin; Kim, Jung-Hwan; Krausz, Kristopher W.; Fang, Zhong-Ze; Jiang, Changtao; Yang, Julin; Gonzalez, Frank J.

    2014-01-01

    Overdose of acetaminophen (APAP) can cause acute liver injury that is sometimes fatal, requiring efficient pharmacological intervention. The traditional Chinese herb Bupleurum falcatum has been widely used for the treatment of several liver diseases in eastern Asian countries, and saikosaponin d (SSd) is one of its major pharmacologically-active components. However, the efficacy of Bupleurum falcatum or SSd on APAP toxicity remains unclear. C57BL/6 mice were administered SSd intraperitoneally once daily for five days, followed by APAP challenge. Biochemical and pathological analysis revealed that mice treated with SSd were protected against APAP-induced hepatotoxicity. SSd markedly suppressed phosphorylation of nuclear factor kappa B (NF-kB) and signal transducer and activator of transcription 3 (STAT3) and reversed the APAP-induced increases in the target genes of NF-kB, such as pro-inflammatory cytokine Il6 and Ccl2, and those of STAT3, such as Socs3, Fga, Fgb and Fgg. SSd also enhanced the expression of the anti-inflammatory cytokine Il10 mRNA. Collectively, these results demonstrate that SSd protects mice from APAP-induced hepatotoxicity mainly through down-regulating NF-kB- and STAT3-mediated inflammatory signaling. This study unveils one of the possible mechanisms of hepatoprotection caused by Bupleurum falcatum and/or SSd. PMID:25265579

  5. Ferulic acid attenuated acetaminophen-induced hepatotoxicity though down-regulating the cytochrome P 2E1 and inhibiting toll-like receptor 4 signaling-mediated inflammation in mice

    PubMed Central

    Yuan, Junhui; Ge, Kuang; Mu, Junhuan; Rong, Jiang; Zhang, Li; Wang, Bin; Wan, Jingyuan; Xia, Gong

    2016-01-01

    Ferulic acid (FA), a phenolic acid which is abundant in vegetables and fruits, has been reported to exert anti-oxidative and anti-inflammatory activities. In the present study, the pharmacological effects and the underlying mechanisms of FA in mice with acetaminophen-induced hepatotoxicity were investigated. Our results revealed that FA pretreatment inhibited the augments of serum aminotransferases in a dose-dependent manner and attenuated the hepatic histopathological abnormalities and hepatocellular apoptosis in acetaminophen (APAP) exposed mice. Moreover, FA inhibited the expression of cytochrome P450 2E1 (CYP2E1), enhanced the activities of superoxide dismutase (SOD) and catalase (CAT) as well as the contents of glutathione (GSH). Furthermore, FA markedly attenuated acetaminophen-induced serum tumor necrosis factor (TNF)-α and interleukin (IL)-1β production, suppressed Toll-like receptor (TLR) 4 expression and dampened p38 mitogen-activated (MAPK) and nuclear factor kappa (NF-κB) activation. These data suggested that FA could effectively protect against APAP-induced liver injury by down-regulated expression of CYP 2E1 and the suppression of TLR4-mediated inflammatory responses. PMID:27830004

  6. The effect of aging on acetaminophen pharmacokinetics, toxicity and Nrf2 in Fischer 344 rats.

    PubMed

    Mach, John; Huizer-Pajkos, Aniko; Cogger, Victoria C; McKenzie, Catriona; Le Couteur, David G; Jones, Brett E; de Cabo, Rafael; Hilmer, Sarah N

    2014-04-01

    We investigated the effect of aging on hepatic pharmacokinetics and the degree of hepatotoxicity following a toxic dose of acetaminophen. Young and old male Fischer 344 rats were treated with 800 mg/kg acetaminophen (young n = 8, old n = 5) or saline (young n = 9, old n = 9). Serum measurements showed old rats treated with acetaminophen had significantly lower serum alanine aminotransferase and higher acetaminophen and acetaminophen glucuronide levels and creatinine, compared with acetaminophen treated young rats (p < .05). Immunoblotting and activity assays showed old saline-treated rats had twofold lower cytochrome P450 2E1 activity and threefold higher NAD(P)H quinone oxireductase 1 protein expression and activity than young saline-treated rats (p < .05), although Nrf2, glutathione cysteine ligase-modulatory subunit, glutathione cysteine ligase-catalytic subunit, and cytochrome P450 2E1 protein expressions were unchanged. Primary hepatocytes isolated from young rats treated with 10 mM acetaminophen had lower survival than those from old rats (52.4% ± 5.8%, young; 83.6% ± 1.7%, old, p < .05). The pharmacokinetic changes described may decrease susceptibility to acetaminophen-induced hepatotoxicity but may increase risk of nephrotoxicity in old age.

  7. The gap junction inhibitor 2-aminoethoxy-diphenyl-borate protects against acetaminophen hepatotoxicity by inhibiting cytochrome P450 enzymes and c-jun N-terminal kinase activation

    SciTech Connect

    Du, Kuo; Williams, C. David; McGill, Mitchell R.; Xie, Yuchao; Farhood, Anwar; Vinken, Mathieu; Jaeschke, Hartmut

    2013-12-15

    Acetaminophen (APAP) hepatotoxicity is the leading cause of acute liver failure in the US. Although many aspects of the mechanism are known, recent publications suggest that gap junctions composed of connexin32 function as critical intercellular communication channels which transfer cytotoxic mediators into neighboring hepatocytes and aggravate liver injury. However, these studies did not consider off-target effects of reagents used in these experiments, especially the gap junction inhibitor 2-aminoethoxy-diphenyl-borate (2-APB). In order to assess the mechanisms of protection of 2-APB in vivo, male C56Bl/6 mice were treated with 400 mg/kg APAP to cause extensive liver injury. This injury was prevented when animals were co-treated with 20 mg/kg 2-APB and was attenuated when 2-APB was administered 1.5 h after APAP. However, the protection was completely lost when 2-APB was given 4–6 h after APAP. Measurement of protein adducts and c-jun-N-terminal kinase (JNK) activation indicated that 2-APB reduced both protein binding and JNK activation, which correlated with hepatoprotection. Although some of the protection was due to the solvent dimethyl sulfoxide (DMSO), in vitro experiments clearly demonstrated that 2-APB directly inhibits cytochrome P450 activities. In addition, JNK activation induced by phorone and tert-butylhydroperoxide in vivo was inhibited by 2-APB. The effects against APAP toxicity in vivo were reproduced in primary cultured hepatocytes without use of DMSO and in the absence of functional gap junctions. We conclude that the protective effect of 2-APB was caused by inhibition of metabolic activation of APAP and inhibition of the JNK signaling pathway and not by blocking connexin32-based gap junctions. - Highlights: • 2-APB protected against APAP-induced liver injury in mice in vivo and in vitro • 2-APB protected by inhibiting APAP metabolic activation and JNK signaling pathway • DMSO inhibited APAP metabolic activation as the solvent of 2-APB

  8. Hepato-protective effects of six schisandra lignans on acetaminophen-induced liver injury are partially associated with the inhibition of CYP-mediated bioactivation.

    PubMed

    Jiang, Yiming; Fan, Xiaomei; Wang, Ying; Tan, Huasen; Chen, Pan; Zeng, Hang; Huang, Min; Bi, Huichang

    2015-04-25

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Schisandra fructus is widely-used traditional Chinese medicine which possesses hepato-protective potential. Schisandrin A (SinA), Schisandrin B (SinB), Schisandrin C (SinC), Schisandrol A (SolA), Schisandrol B (SolB), and Schisantherin A (SthA) are the major bioactive lignans. Most recently, we found SolB exerts significant hepato-protection against APAP-induced liver injury. In this study, the protective effects of the other five schisandra lignans against APAP-induced acute hepatotoxicity in mice were investigated and compared with that of SolB. The results of morphological and biochemical assessment clearly demonstrated significant protective effects of SinA, SinB, SinC, SolA, SolB, and SthA against APAP-induced liver injury. Among these schisandra lignans, SinC and SolB exerted the strongest hepato-protective effects against APAP-induced hepatotoxicity. Six lignans pretreatment before APAP dosing could prevent the depletions of total liver glutathione (GSH) and mitochondrial GSH caused by APAP. Additionally, the lignans treatment inhibited the enzymatic activities of three CYP450 isoforms (CYP2E1, CYP1A2, and CYP3A11) related to APAP bioactivation, and further decreased the formation of APAP toxic intermediate N-acetyl-p-benzoquinone imine (NAPQI) in mouse microsomal incubation system. This study demonstrated that SinA, SinB, SinC, SolA, SolB and SthA exhibited significant protective actions toward APAP-induced liver injury, which was partially associated with the inhibition of CYP-mediated APAP bioactivation.

  9. 3-O-Hydroxytyrosol glucuronide and 4-O-hydroxytyrosol glucuronide reduce endoplasmic reticulum stress in vitro.

    PubMed

    Giordano, Elena; Dangles, Olivier; Rakotomanomana, Njara; Baracchini, Silvia; Visioli, Francesco

    2015-10-01

    Endoplasmic reticulum (ER) stress is important for atherosclerosis development and is mediated by the unfolded protein response (UPR). In this work, we synthesized two among the most physiologically-prominent hydroxytyrosol HT hepatic metabolites, i.e. 3-O-HT glucuronide and 4-O-HT glucuronide and we tested their activities on ER stress (in human hepatocarcinoma HepG2 cells), to gain further insight into the cardiopreventive properties of HT, extra virgin olive oil, and the Mediterranean diet. We report that 3-O-HT glucuronide and 4-O-HT glucuronide inhibit tunicamycin-induced ER stress. As compared with the effects of the parent molecule, 3-O-HT glucuronide and 4-O-HT glucuronide at 10 μM and 25 μM alone induced a milder change in mRNA expression levels of both CCAAT-enhancer-binding protein homologous protein (CHOP) and glucose regulated protein GRP78 immunoglobulin heavy chain binding protein (BiP). In conclusion, we add further evidence to the hypothesis that the HT intake might be atheroprotective and reiterate the usefulness to preferably use high-quality, high-(poly)phenol extra virgin olive oil as a prominent condiment.

  10. Acetaminophen and Codeine

    MedlinePlus

    The combination of acetaminophen and codeine comes as a tablet, capsule, and liquid to take by mouth. It usually is taken every 6 ... explain any part you do not understand. Take acetaminophen and codeine exactly as directed.Codeine can be ...

  11. Use of Arctium lappa Extract Against Acetaminophen-Induced Hepatotoxicity in Rats

    PubMed Central

    El-Kott, Attalla Farag; Bin-Meferij, Mashael Mohammed

    2015-01-01

    Background Severe destructive hepatic injuries can be induced by acetaminophen overdose and may lead to acute hepatic failure. Objective To investigate the ameliorative effects of Arctium lappa root extract on acetaminophen-induced hepatotoxicity. Methods Rats were divided into 4 groups: normal control group, Arctium lappa extract group, acetaminophen-injected group, and acetaminophen treated with Arctium lappa extract group. Results The treatment with Arctium lappa extract reduced serum alanine transaminase, aspartate aminotransferase, and alkaline phosphatase in the acetaminophen group when compared with the control group. DNA fragments in the acetaminophen-injected group were also significantly increased (P < 0.05). The comet assay revealed increased detaching tail length and DNA concentration during the hepatic toxicity in the acetaminophen group. The malondialdehyde content was inhibited by Arctium lappa treatment (12.97±0.89 nmol/mg) when compared with the acetaminophen-treated-only group (12.97±0.89 nmol/mg). Histopathologic examination revealed that acetaminophen administration produced hepatic cell necrosis, infiltrate of lymphocytes, and vacuolation that were associated with the acetaminophen-treated animal group, but the degree of acetaminophen-induced hepatotoxicity was mediated by treatment with Arctium lappa extract. Conclusions Arctium lappa can prevent most of the hepatic tissue damage caused by acetaminophen overdose in rats. PMID:26543508

  12. Apigenin-7-O-β-D-glucuronide inhibits LPS-induced inflammation through the inactivation of AP-1 and MAPK signaling pathways in RAW 264.7 macrophages and protects mice against endotoxin shock.

    PubMed

    Hu, Weicheng; Wang, Xinfeng; Wu, Lei; Shen, Ting; Ji, Lilian; Zhao, Xihong; Si, Chuan-Ling; Jiang, Yunyao; Wang, Gongcheng

    2016-02-01

    Apigenin-7-O-β-D-glucuronide (AG), an active flavonoid derivative isolated from the agricultural residue of Juglans sigillata fruit husks, possesses multiple pharmacological activities, including anti-oxidant, anti-complement, and aldose reductase inhibitory activities. To date, no report has identified the anti-inflammatory mechanisms of AG. This study was therefore designed to characterize the molecular mechanisms of AG on lipopolysaccharide (LPS)-induced inflammatory cytokines in RAW 264.7 cells and on endotoxin-induced shock in mice. AG suppressed the release of nitric oxide (NO), prostaglandin E2 (PGE2), and tumour necrosis factor-α (TNF-α) in LPS-stimulated RAW 264.7 macrophages in a dose-dependent manner without affecting cell viability. Additionally, AG suppressed LPS-induced mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α. AG treatment decreased the translocation of c-Jun into the nucleus, and decreased activator protein-1 (AP-1)-mediated luciferase activity through the inhibition of both p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) phosphorylation. Consistent with the in vitro observations, AG protected mice from LPS-induced endotoxin shock by inhibiting proinflammatory cytokine production. Taken together, these results suggest that AG may be used as a source of anti-inflammatory agents as well as a dietary complement for health promotion.

  13. Simultaneous quantification of acetaminophen and five acetaminophen metabolites in human plasma and urine by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry: Method validation and application to a neonatal pharmacokinetic study.

    PubMed

    Cook, Sarah F; King, Amber D; van den Anker, John N; Wilkins, Diana G

    2015-12-15

    Drug metabolism plays a key role in acetaminophen (paracetamol)-induced hepatotoxicity, and quantification of acetaminophen metabolites provides critical information about factors influencing susceptibility to acetaminophen-induced hepatotoxicity in clinical and experimental settings. The aims of this study were to develop, validate, and apply high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) methods for simultaneous quantification of acetaminophen, acetaminophen-glucuronide, acetaminophen-sulfate, acetaminophen-glutathione, acetaminophen-cysteine, and acetaminophen-N-acetylcysteine in small volumes of human plasma and urine. In the reported procedures, acetaminophen-d4 and acetaminophen-d3-sulfate were utilized as internal standards (IS). Analytes and IS were recovered from human plasma (10μL) by protein precipitation with acetonitrile. Human urine (10μL) was prepared by fortification with IS followed only by sample dilution. Calibration concentration ranges were tailored to literature values for each analyte in each biological matrix. Prepared samples from plasma and urine were analyzed under the same HPLC-ESI-MS/MS conditions, and chromatographic separation was achieved through use of an Agilent Poroshell 120 EC-C18 column with a 20-min run time per injected sample. The analytes could be accurately and precisely quantified over 2.0-3.5 orders of magnitude. Across both matrices, mean intra- and inter-assay accuracies ranged from 85% to 112%, and intra- and inter-assay imprecision did not exceed 15%. Validation experiments included tests for specificity, recovery and ionization efficiency, inter-individual variability in matrix effects, stock solution stability, and sample stability under a variety of storage and handling conditions (room temperature, freezer, freeze-thaw, and post-preparative). The utility and suitability of the reported procedures were illustrated by analysis of pharmacokinetic samples

  14. Effects of kale ingestion on pharmacokinetics of acetaminophen in rats.

    PubMed

    Yamasaki, Izumi; Uotsu, Nobuo; Yamaguchi, Kohji; Takayanagi, Risa; Yamada, Yasuhiko

    2011-12-01

    Kale is a cruciferous vegetable (Brassicaceae) that contains a large amount of health-promoting phytochemicals. The chronic ingestion of cabbage of the same family is known to accelerate conjugating acetaminophen (AA) and decrease the plasma AA level. Therefore, we examined to clarify the effects of kale on the pharmacokinetics of AA, its glucuronide (AA-G) and sulfate (AA-S). AA was orally administered to rats pre-treated with kale or cabbage (2000 mg/kg/day) for one week. Blood samples were collected from the jugular vein, and the concentrations of AA, AA-G and AA-S were determined. In results, kale ingestion induced an increase in the area under the concentration-time curve (AUC) and a decrease in the clearance of AA, whereas cabbage had almost no influence. In addition, there were significant differences in the AUC of AA-G between the control and kale groups. mRNA expression levels of UDP-glucuronosyltransferases, the enzymes involved in glucuronidation, in the kale group were significantly higher than those in the control group. In conclusion, kale ingestion increased the plasma concentrations of both AA and AA-G. The results suggest that kale ingestion accelerates the glucuronidation of AA, but an increase of plasma AA levels has a different cause than the cause of glucuronidation.

  15. Regioselective Glucuronidation of Diosmetin and Chrysoeriol by the Interplay of Glucuronidation and Transport in UGT1A9-Overexpressing HeLa Cells

    PubMed Central

    Zhao, Min; Chen, Qingwei; Wang, Liping; Jiang, Huangyu; Luo, Feifei; Zhu, Lijun; Lu, Linlin; Wang, Xinchun; Liu, Zhongqiu

    2016-01-01

    This study aimed to determine the reaction kinetics of the regioselective glucuronidation of diosmetin and chrysoeriol, two important methylated metabolites of luteolin, by human liver microsomes (HLMs) and uridine-5′-diphosphate glucuronosyltransferase (UGTs) enzymes. This study also investigated the effects of breast cancer resistance protein (BCRP) on the efflux of diosmetin and chrysoeriol glucuronides in HeLa cells overexpressing UGT1A9 (HeLa—UGT1A9). After incubation with HLMs in the presence of UDP-glucuronic acid, diosmetin and chrysoeriol gained two glucuronides each, and the OH—in each B ring of diosmetin and chrysoeriol was the preferable site for glucuronidation. Screening assays with 12 human expressed UGT enzymes and chemical-inhibition assays demonstrated that glucuronide formation was almost exclusively catalyzed by UGT1A1, UGT1A6, and UGT1A9. Importantly, in HeLa—UGT1A9, Ko143 significantly inhibited the efflux of diosmetin and chrysoeriol glucuronides and increased their intracellular levels in a dose-dependent manner. This observation suggested that BCRP-mediated excretion was the predominant pathway for diosmetin and chrysoeriol disposition. In conclusion, UGT1A1, UGT1A6, and UGT1A9 were the chief contributors to the regioselective glucuronidation of diosmetin and chrysoeriol in the liver. Moreover, cellular glucuronidation was significantly altered by inhibiting BCRP, revealing a notable interplay between glucuronidation and efflux transport. Diosmetin and chrysoeriol possibly have different effects on anti-cancer due to the difference of UGT isoforms in different cancer cells. PMID:27832172

  16. Aspirin curtails the acetaminophen-induced rise in brain norepinephrine levels.

    PubMed

    Maharaj, Himant; Maharaj, Deepa S; Saravanan, Karruppagounder S; Mohanakumar, Kochupurackal P; Daya, Santy

    2004-06-01

    We previously showed that acetaminophen administration to rats increases forebrain serotonin levels as a result of the inhibition of liver tryptophan-2,3-dioxygenase (TDO). In this study we determined whether aspirin alone and in combination with acetaminophen could further influence brain serotonin as well as norepinephrine levels and if so whether the status of the liver TDO activity would be altered. The results show that acetaminophen alone increases brain serotonin as well as norepinephrine levels with a concomitant inhibition of liver TDO activity. In contrast, aspirin did not alter the levels of these monoamines but increased serotonin turnover in the brain while acetaminophen decreased the turnover. When combined with acetaminophen, aspirin overrides the reduced serotonin turnover induced by acetaminophen. This report demonstrates the potential of these agents to alter neurotransmitter levels in the brain.

  17. Acetaminophen hepatotoxicity and sterile inflammation: The mechanism of protection of Chlorogenic acid.

    PubMed

    Jaeschke, Hartmut

    2016-01-05

    Acetaminophen hepatotoxicity is characterized by extensive necrotic cell death and a sterile inflammatory response. A recent report suggested that a therapeutic intervention with chlorogenic acid, a dietary polyphenolic compound, protects against acetaminophen-induced liver injury by inhibiting the inflammatory injury. The purpose of this letter is to discuss a number of reasons why the protective mechanism of chlorogenic acid against acetaminophen hepatotoxicity does not involve an anti-inflammatory effect and provides an alternative explanation for the observed protection.

  18. Autism and Phthalate Metabolite Glucuronidation

    ERIC Educational Resources Information Center

    Stein, T. Peter; Schluter, Margaret D.; Steer, Robert A.; Ming, Xue

    2013-01-01

    Exposure to environmental chemicals may precipitate autism spectrum disorders (ASD) in genetically susceptible children. Differences in the efficiency of the glucuronidation process may substantially modulate substrate concentrations and effects. To determine whether the efficiency of this pathway is compromised in children with ASD, we measured…

  19. Microdose study of 14C-acetaminophen with accelerator mass spectrometry to examine pharmacokinetics of parent drug and metabolites in healthy subjects.

    PubMed

    Tozuka, Z; Kusuhara, H; Nozawa, K; Hamabe, Y; Ikushima, I; Ikeda, T; Sugiyama, Y

    2010-12-01

    A study of the pharmacokinetics of (14)C-labeled acetaminophen (AAP) was performed in healthy Japanese subjects receiving an oral microdose of the drug. After separation by high-performance liquid chromatography (HPLC), the levels of AAP and its metabolites in the pooled plasma specimens were quantified using accelerator mass spectrometry (AMS). The total body clearance (CL(tot))/bioavailability (F) of AAP was within the variation in the reported values at therapeutic doses, indicating the linearity of AAP pharmacokinetics. AAP-glucuronide (Glu) and AAP-4-O-sulfate satisfied the criteria of safety testing of drug metabolites. AMS could detect AAP-Cys, the active metabolite of AAP conjugated with cysteine, in the urine. Probenecid prolonged the systemic elimination of total radioactivity and caused a marked decrease in AAP-Glu levels in plasma. Probenecid likely inhibited the glucuronidation of AAP and the renal elimination of AAP-4-O-sulfate. Microdosing of (14)C-labeled drug followed by AMS is a powerful tool that can be used in the early phase of drug development for pharmacokinetic analysis of drugs and their metabolites and for detecting the formation of active metabolites in humans.

  20. Ferroptosis is Involved in Acetaminophen Induced Cell Death.

    PubMed

    Lőrincz, Tamás; Jemnitz, Katalin; Kardon, Tamás; Mandl, József; Szarka, András

    2015-09-01

    The recently described form of programmed cell death, ferroptosis can be induced by agents causing GSH depletion or the inhibition of GPX4. Ferroptosis clearly shows distinct morphologic, biochemical and genetic features from apoptosis, necrosis and autophagy. Since NAPQI the highly reactive metabolite of the widely applied analgesic and antipyretic, acetaminophen induces a cell death which can be characterized by GSH depletion, GPX inhibition and caspase independency the involvement of ferroptosis in acetaminophen induced cell death has been investigated. The specific ferroptosis inhibitor ferrostatin-1 failed to elevate the viability of acetaminophen treated HepG2 cells. It should be noticed that these cells do not form NAPQI due to the lack of phase I enzyme expression therefore GSH depletion cannot be observed. However in the case of acetaminophen treated primary mouse hepatocytes the significant elevation of cell viability could be observed upon ferrostatin-1 treatment. Similar to ferrostatin-1 treatment, the addition of the RIP1 kinase inhibitor necrostatin-1 could also elevate the viability of acetaminophen treated primary hepatocytes. Ferrostatin-1 has no influence on the expression of CYP2E1 or on the cellular GSH level which suggest that the protective effect of ferrostatin-1 in APAP induced cell death is not based on the reduced metabolism of APAP to NAPQI or on altered NAPQI conjugation by cellular GSH. Our results suggest that beyond necroptosis and apoptosis a third programmed cell death, ferroptosis is also involved in acetaminophen induced cell death in primary hepatocytes.

  1. Identification of the human UDP-glucuronosyltransferase isoforms involved in the glucuronidation of the phytochemical ferulic acid.

    PubMed

    Li, Xiaojun; Shang, Liang; Wu, Yaohua; Abbas, Suzanne; Li, Dong; Netter, Patrick; Ouzzine, Mohamed; Wang, Hui; Magdalou, Jacques

    2011-01-01

    Ferulic acid (FA), a member of the hydroxycinnamate family, is an abundant dietary antioxidant that may offer beneficial effects against cancer, cardiovascular disease, diabetes, osteoarthritis and Alzheimer's disease. In this study, evidence for sulfation and glucuronidation of FA was investigated upon incubation with human liver microsomes and cytosol. Two main glucuronides, M1 (ether O-glucuronide) and M2 (ester acylglucuronide), were formed with a similar affinity (apparent K(m) 3.53 and 5.15 mM, respectively). A phenol sulfoconjugate was also formed with a higher affinity (K(m) 0.53 mM). Identification of the UDP-glucuronosyltransferase (UGT) isoforms involved in FA glucuronidation was investigated with 12 human recombinant enzymes. FA was mainly glucuronidated by UGT1A isoforms and by UGT2B7. UGT1A4, 2B4, 2B15 and 2B17 failed to glucuronidate the substance. Examination of the kinetic constants revealed that FA was mainly glucuronidated by UGT1A1 at the two nucleophilic groups. UGT1A3 was able to glucuronidate these two positions with the same, but low, efficiency. UGT1A6 and 1A8 were involved in the formation of the ether glucuronide only, whereas UGT1A7, 1A10 and 2B7 preferentially glucuronidated the carboxyl group. Moreover, octyl gallate, a marker substrate of UGT1A1, competitively inhibited FA glucuronidation mediated by this isoform. Altogether, the results suggest that FA glucuronidation is primarily mediated by UGT1A1.

  2. Inhibitory effects of Schisandra chinensis on acetaminophen-induced hepatotoxicity.

    PubMed

    Wang, Kun-Peng; Bai, Yu; Wang, Jian; Zhang, Jin-Zhen

    2014-05-01

    Schisandra chinensis is a well-known traditional medicinal herb. Acetaminophen is a commonly used over-the-counter analgesic and overdose of acetaminophen was the most frequent cause of acute liver failure. However, no studies have demonstrated the role of Schisandra chinensis in acetaminophen-induced acute liver failure to the best of our knowledge. In this study, an acute liver injury model was established in mice using acetaminophen. The protective role of Schisandra chinensis was detected by histopathological analysis, and measurement of the serum transaminase levels and hepatic Cyp activity levels in the mouse model. Subsequently, hepatocytes were isolated from the livers of the mouse model. The cell cycle, apoptosis, mitochondrial membrane potential and reactive oxygen species were determined using flow cytometry. Cell proliferation and 26S proteasome activity were determined using spectrophotometry. Schisandra chinensis was found to resist acetaminophen-induced hepatotoxicity by protecting mitochondria and lysosomes and inhibiting the phosphor-c-Jun N-terminal kinase signaling pathway. These findings provide a novel application of Schisandra chinensis against acetaminophen-induced acute liver failure.

  3. The effects of acetaminophen on pharmacokinetics and pharmacodynamics of warfarin.

    PubMed

    Kwan, D; Bartle, W R; Walker, S E

    1999-01-01

    The oral anticoagulant warfarin is clinically administered as a racemic mixture of two enantiomers, (R) and (S). Many relevant drug interactions with warfarin have been attributed to the specific metabolic inhibition of the elimination of the more pharmacologically active (S)-enantiomer. To investigate reports that acetaminophen can potentiate the anticoagulant effect of warfarin, 20 healthy male volunteers were each given single oral 20 mg doses of racemic warfarin on three separate occasions: (1) alone, (2) after 1 day of acetaminophen (4 g/d), and (3) after 2 weeks of acetaminophen (4 g/d). The urinary excretion pattern of acetaminophen and its metabolites was not significantly altered over its course of administration. The (R)- and (S)-enantiomers of warfarin exhibited significantly different pharmacokinetic properties. However, acetaminophen did not alter the disposition of either (R)- or (S)-warfarin. All subjects exhibited a pharmacodynamic response to racemic warfarin. The response was not significantly altered in the presence of acute or chronic acetaminophen dosing, as assessed by prothrombin time and factor VII concentrations.

  4. Abnormal serum transaminases following therapeutic doses of acetaminophen in the absence of known risk factors.

    PubMed

    Kwan, D; Bartle, W R; Walker, S E

    1995-09-01

    J.M., a healthy, 25-year-old male, volunteered for a study involving warfarin and acetaminophen. Acetaminophen 1 g four times a day was started for 21 days. Liver function tests taken at regular intervals for the first 12 days were unremarkable. On day 18, however, aspartate aminotransferase (AST) was 527 IU/liter and alanine aminotransferase (ALT) was 166 IU/liter. Acetaminophen was discontinued and serum transaminase levels returned to baseline levels two weeks later (AST = 26, ALT = 20). Analysis of J.M.'s urine samples over the first 18 days showed excretion patterns of glucuronide, sulfate, and glutathione derived cysteine and mercapturic acid conjugates were similar to the other subjects in the study. Acetaminophen causes hepatotoxicity in overdose or malnourished or alcoholic patients, none of which applied to our subject. Differences in metabolic activation and capacity for glutathione synthesis can predispose individuals given therapeutic doses of acetaminophen to adverse effects. Failure to detoxify a highly reactive metabolite, formed by P-450 metabolism, via glutathione conjugation is responsible for the development of acute hepatic necrosis. Accumulation of the toxic metabolite due to depleted glutathione stores may have occurred with prolonged high dosing in our subject and been responsible for his abnormal rise in liver enzymes.

  5. Acetaminophen protects brain endothelial cells against oxidative stress.

    PubMed

    Tripathy, Debjani; Grammas, Paula

    2009-05-01

    Increasing evidence suggests that acetaminophen has unappreciated anti-oxidant and anti-inflammatory properties. Drugs that affect oxidant and inflammatory stress in the brain are of interest because both processes are thought to contribute to the pathogenesis of neurodegenerative disease. The objective of this study is to determine whether acetaminophen affects the response of brain endothelial cells to oxidative stress. Cultured brain endothelial cells are pre-treated with acetaminophen and then exposed to the superoxide-generating compound menadione (25 microM). Cell survival, inflammatory protein expression, and anti-oxidant enzyme activity are measured. Menadione causes a significant (p<0.001) increase in endothelial cell death as well as an increase in RNA and protein levels of tumor necrosis factor alpha, interleukin-1, macrophage inflammatory protein alpha, and RANTES. Menadione also evokes a significant (p<0.001) increase in the activity of the anti-oxidant enzyme superoxide dismutase (SOD). Pre-treatment of endothelial cell cultures with acetaminophen (25-100 microM) increases endothelial cell survival and inhibits menadione-induced expression of inflammatory proteins and SOD activity. In addition, we document, for the first time, that acetaminophen increases expression of the anti-apoptotic protein Bcl2. Suppressing Bcl2 with siRNA blocks the pro-survival effect of acetaminophen. These data show that acetaminophen has anti-oxidant and anti-inflammatory effects on the cerebrovasculature and suggest a heretofore unappreciated therapeutic potential for this drug in neurodegenerative diseases such as Alzheimer's disease that are characterized by oxidant and inflammatory stress.

  6. Wuzhi tablet (Schisandra Sphenanthera extract) protects against acetaminophen-induced hepatotoxicity by inhibition of CYP-mediated bioactivation and regulation of NRF2-ARE and p53/p21 pathways.

    PubMed

    Fan, Xiaomei; Jiang, Yiming; Wang, Ying; Tan, Huasen; Zeng, Hang; Wang, Yongtao; Chen, Pan; Qu, Aijuan; Gonzalez, Frank J; Huang, Min; Bi, Huichang

    2014-12-01

    Schisandra sphenanthera is widely used as a tonic and restorative in many countries to enhance the function of liver and other organs. Wuzhi tablet (WZ) is a preparation of an ethanol extract of Schisandra sphenanthera. Our previous study demonstrated that WZ exerted a protective effect toward acetaminophen (APAP)-induced hepatotoxicity. However, the molecular mechanisms of this protection remain unclear. This study aimed to determine what molecular pathways contributed to the hepatoprotective effects of WZ against APAP toxicity. Administration of WZ 3 days before APAP treatment significantly attenuated APAP hepatotoxicity in a dose-dependent manner and reduced APAP-induced JNK activation. Treatment with WZ resulted in potent inhibition of CYP2E1, CYP3A11, and CYP1A2 activities and then caused significant inhibition of the formation of the oxidized APAP metabolite N-acetyl-p-benzoquinone imine-reduced glutathione. The expression of NRF2 was increased after APAP and/or WZ treatment, whereas KEAP1 levels were decreased. The protein expression of NRF2 target genes including Gclc, Gclm, Ho-1, and Nqo1 was significantly increased by WZ treatment. Furthermore, APAP increased the levels of p53 and its downstream gene p21 to trigger cell cycle arrest and apoptosis, whereas WZ pretreatment could inhibit p53/p21 signaling to induce cell proliferation-associated proteins including cyclin D1, CDK4, PCNA, and ALR to promote hepatocyte proliferation. This study demonstrated that WZ prevented APAP-induced liver injury by inhibition of cytochrome P450-mediated APAP bioactivation, activation of the NRF2-antioxidant response element pathway to induce detoxification and antioxidation, and regulation of the p53, p21, cyclin D1, CDK4, PCNA, and ALR to facilitate liver regeneration after APAP-induced liver injury.

  7. Regioselective Glucuronidation of Flavonols by Six Human UGT1A Isoforms

    PubMed Central

    Wu, Baojian; Hu, Ming

    2012-01-01

    Purpose Flavonols, a class of polyphenols, show a variety of biological activities such as antioxidant and anticancer. However, rapid in vivo O-glucuronidation posed a challenge to develop them as therapeutic agents. The objective of this paper is to determine the regioselective glucuronidation of flavonols by UGT1A isoforms (i.e., UGT1A1, UGT1A3, UGT1A7, UGT1A8, UGT1A9 and UGT1A10). Methods The kinetics of UGT1A1-, 1A3- and 1A7~1A10-mediated metabolisms of four flavonols that contain 7-OH group were characterized and kinetic parameters (Km, Vmax and intrinsic clearance (CLint=Vmax/Km)) were determined. Results UGT1A1 and 1A3 regioselectively metabolized 7-OH, whereas UGT1A7~1A10 preferred to glucuronidate 3-OH group. UGT1A1 and UGT1A9 were the most efficient conjugating enzymes with Km of ≤1 µM and Vmax/Km of >3 ml/min/mg protein, resulting in a CLint value as high as 6 ml/min/mg protein. Additionally, the four flavonols generally strongly self-inhibited the UGT1A1-mediated glucuronidation, with Ks (substrate inhibition constant) of ≤ 5.4 µM. Conclusion UGT1A isoforms displayed distinct positional preferences between 3-OH and 7-OH in the glucuronidation of flavonols. The differentiated kinetics properties between 3-O- and 7-O- glucuronidation indicated that at least two distinct binding modes within the catalytic domain were responsible for the formation of these two glucuronide isomers. PMID:21472492

  8. Quercitrin from Toona sinensis (Juss.) M.Roem. Attenuates Acetaminophen-Induced Acute Liver Toxicity in HepG2 Cells and Mice through Induction of Antioxidant Machinery and Inhibition of Inflammation.

    PubMed

    Truong, Van-Long; Ko, Se-Yeon; Jun, Mira; Jeong, Woo-Sik

    2016-07-15

    Quercitrin is found in many kinds of vegetables and fruits, and possesses various bioactive properties. The aim of the present study was to elucidate hepatoprotective mechanisms of quercitrin isolated from Toona sinensis (Juss.) M.Roem. (syn. Cedrela sinensis Juss.), using acetaminophen (APAP)-treated HepG2 cell and animal models. In an in vitro study, quercitrin suppressed the production of reactive oxygen species and enhanced expression of nuclear factor E2-related factor 2 (Nrf2), activity of antioxidant response element (ARE)-reporter gene, and protein levels of NADPH: quinone oxidoreductase 1 (NQO1), catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase 2 (SOD-2) in APAP-treated HepG2 cells. In an in vivo study, Balb/c mice were orally administered with 10 or 50 mg/kg of quercitrin for 7 days and followed by the injection with single dose of 300 mg/kg APAP. Quercitrin decreased APAP-caused elevation of alanine aminotransferase and aspartate aminotransferase levels, liver necrosis, the expression of pro-inflammatory factors including inducible nitric oxide synthase, cyclooxygenase 2 and inerleukin-1β, and phosphorylation of kinases including c-Jun N-terminal kinase and p38. Quercitrin restored protein levels of Nrf2, NQO1 and activities and expressions of CAT, GPx, SOD-2. The results suggested that quercitrin attenuates APAP-induced liver damage by the activation of defensive genes and the inhibition of pro-inflammatory genes via the suppressions of JNK and p38 signaling.

  9. Liquid microjunction surface sampling of acetaminophen, terfenadine and their metabolites in thin tissue sections

    DOE PAGES

    Kertesz, Vilmos; Paranthaman, Nithya; Moench, Paul; ...

    2014-10-01

    The aim of this paper was to evaluate the analytical performance of a fully automated droplet-based surface-sampling system for determining the distribution of the drugs acetaminophen and terfenadine, and their metabolites, in rat thin tissue sections. The following are the results: The rank order of acetaminophen concentration observed in tissues was stomach > small intestine > liver, while the concentrations of its glucuronide and sulfate metabolites were greatest in the liver and small intestine. Terfenadine was most concentrated in the liver and kidney, while its major metabolite, fexofenadine, was found in the liver and small intestine. In conclusion, the spatialmore » distributions of both drugs and their respective metabolites observed in this work were consistent with previous studies using radiolabeled drugs.« less

  10. Liquid microjunction surface sampling of acetaminophen, terfenadine and their metabolites in thin tissue sections

    SciTech Connect

    Kertesz, Vilmos; Paranthaman, Nithya; Moench, Paul; Catoire, Alexandre; Flarakos, Jimmy; Van Berkel, Gary J.

    2014-10-01

    The aim of this paper was to evaluate the analytical performance of a fully automated droplet-based surface-sampling system for determining the distribution of the drugs acetaminophen and terfenadine, and their metabolites, in rat thin tissue sections. The following are the results: The rank order of acetaminophen concentration observed in tissues was stomach > small intestine > liver, while the concentrations of its glucuronide and sulfate metabolites were greatest in the liver and small intestine. Terfenadine was most concentrated in the liver and kidney, while its major metabolite, fexofenadine, was found in the liver and small intestine. In conclusion, the spatial distributions of both drugs and their respective metabolites observed in this work were consistent with previous studies using radiolabeled drugs.

  11. High-dose acetaminophen inhibits the lethal effect of doxorubicin in HepG2 cells: the role of P-glycoprotein and mitogen-activated protein kinase p44/42 pathway.

    PubMed

    Manov, Irena; Bashenko, Yulia; Eliaz-Wolkowicz, Anat; Mizrahi, Meital; Liran, Oded; Iancu, Theodore C

    2007-09-01

    Doxorubicin (DOX) is a widely used chemotherapeutic drug for human hepatocellular carcinoma (HCC). A major limitation to its effectiveness is the development of multidrug resistance of cancer cells. In clinical trials, patients with advanced HCC were treated with high-dose acetaminophen (HAAP) in an effort to improve the antitumor activity of chemotherapeutics. In this study, we investigated the effect of concomitant treatment of DOX and HAAP on hepatoma-derived HepG2 cells. Viability, cell cycle distribution, and ultrastructure were examined. Unexpectedly, HAAP, when added to DOX-exposed cells, increased cell viability, released cell cycle arrest, and decreased apoptosis. To elucidate the mechanisms by which HAAP reduces the DOX lethal effect to HepG2 cells, we investigated the multidrug resistance P-glycoprotein (P-gp) and p44/42-mitogen-activated protein kinase (MAPK) pathways. The P-gp function was enhanced by DOX and HAAP, and it was further stimulated during combined treatment, leading to decreased DOX retention. Verapamil (VRP), when added to DOX + HAAP exposure, increased DOX accumulation and restored DOX-induced toxicity. The increased phospho-p44/42-MAPK level in DOX-exposed cells was inhibited by HAAP. In addition, suppression of p44/42 activation by the p44/42-MAPK inhibitor 2'-amino-3'-methoxyflavone (PD98059) blocked DOX-induced apoptosis. These findings suggest that the antagonistic effect of concomitant DOX + HAAP treatment occurs as a result of interactive stimulation of P-gp, generating decreased intracellular drug concentrations. Furthermore, inhibition of the p44/42-MAPK phosphorylation by HAAP could abolish the DOX-induced cell death pathway. Thus, combined treatment by DOX + HAAP, intended to improve chemotherapeutic efficacy, could have an opposite effect facilitating cancer cell survival.

  12. The common pain of surrealism and death: acetaminophen reduces compensatory affirmation following meaning threats.

    PubMed

    Randles, Daniel; Heine, Steven J; Santos, Nathan

    2013-06-01

    The meaning-maintenance model posits that any violation of expectations leads to an affective experience that motivates compensatory affirmation. We explore whether the neural mechanism that responds to meaning threats can be inhibited by acetaminophen, in the same way that acetaminophen inhibits physical pain or the distress caused by social rejection. In two studies, participants received either acetaminophen or a placebo and were provided with either an unsettling experience or a control experience. In Study 1, participants wrote about either their death or a control topic. In Study 2, participants watched either a surrealist film clip or a control film clip. In both studies, participants in the meaning-threat condition who had taken a placebo showed typical compensatory affirmations by becoming more punitive toward lawbreakers, whereas those who had taken acetaminophen, and those in the control conditions, did not.

  13. Influence of combinations of acetylsalicylic acid, acetaminophen, and diclofenac on platelet aggregation.

    PubMed

    Galliard-Grigioni, Katja S; Fehr, Martin; Reinhart, Walter H

    2008-10-24

    Acetylsalicylic acid (aspirin) is often given together with other nonsteroidal anti-inflammatory drugs and acetaminophen. The latter have been accused in epidemiologic studies to cause an increased cardiovascular risk. We have, therefore, analysed the influence of various such drug combinations on platelet aggregation in vitro. Citrated blood was incubated with either 25 microg/ml acetaminophen, 0.5 microg/ml aspirin, 0.04 microg/ml diclofenac, or buffer; followed by a second of the above-mentioned solutions. After a 20 min incubation, platelet aggregation was assessed with a platelet function analyser (PFA-100), which measures the pore closure time (CT) by aggregating platelets. The length of CT reflects the degree of platelet inhibition. Acetaminophen alone did not affect platelet aggregation. Aspirin and diclofenac both increased CT (184+/-69 s, P<0.01 and 196+/-54 s, P<0.001; control 120+/-13 s). Combinations of either aspirin and diclofenac, aspirin and acetaminophen, or diclofenac and acetaminophen increased CT further (290+/-22 s, 281+/-36 s, 288+/-25 s, respectively, P<0.001). The time sequence of drug application was important: when diclofenac or acetaminophen was added before aspirin, platelet aggregation was less inhibited than when given in opposite order, i.e. aspirin prior to diclofenac or acetaminophen. We conclude that acetaminophen by itself does not affect platelet aggregation, but potentiates the antiaggregatory effect of aspirin or diclofenac. Aspirin given before acetaminophen or diclofenac had a more potent antiaggregatory effect than vice versa. These observations may have clinical implications.

  14. Acetaminophen and Children: Why Dosage Matters

    MedlinePlus

    Healthy Lifestyle Children's health An acetaminophen overdose is serious — and it can happen easier than you might think. ... 29, 2017 Original article: http://www.mayoclinic.org/healthy-lifestyle/childrens-health/in-depth/acetaminophen/art-20046721 . Mayo ...

  15. Lithocholate glucuronide is a cholestatic agent

    SciTech Connect

    Oelberg, D.G.; Chari, M.V.; Little, J.M.; Adcock, E.W.; Lester, R.

    1984-06-01

    Lithocholic acid and its taurine, glycine, and sulfate derivatives are potent cholestatic agents. (3 beta-/sup 3/H)lithocholate 3-O-beta-D-glucuronide was synthesized, and chemical and radiochemical purity were established. The aqueous solubility of lithocholate glucuronide was determined and found to be greater than that of lithocholic acid or several of its derivatives. In the range of concentrations examined, calcium ions precipitated lithocholate glucuronide stoichiometrically. The material was administered to rats prepared with an external biliary fistula. When 17-25 micrograms quantities were administered, 89.1 +/- 4.5% (mean +/- SEM) of the radiolabel was secreted in bile within the first 20 h after administration, the major fraction being secreted in less than 20 min. Four-fifths of the radiolabeled material in bile was the administered unaltered parent compound, while a minor fraction consisted of a more polar derivative(s). We showed that increasing biliary concentrations of more polar derivatives were observed with milligram doses of (3H)lithocholate glucuronide, and with time after the administration of these loading doses. Milligram doses of (3H)lithocholate glucuronide resulted in partial or complete cholestasis. When induced cholestasis was partial, secretion in bile remained the primary excretory route (82.5-105.6% recovery in bile), while, when complete cholestasis was induced, wide tissue distribution of radiolabel was observed. Cholestasis developed rapidly during infusion of (3H)lithocholate glucuronide. Bile flow was diminished within 10-20 min of the start of an infusion of 0.05 mumol, 100 g-1 body weight, minute-1, administered concomitantly with an equimolar infusion of taurocholate. The results establish that lithocholate glucuronide exerts cholestatic effects comparable to those exerted by unconjugated lithocholic acid.

  16. Contribution of acetaminophen-cysteine to acetaminophen nephrotoxicity in CD-1 mice: I. Enhancement of acetaminophen nephrotoxicity by acetaminophen-cysteine

    SciTech Connect

    Stern, Stephan T.; Bruno, Mary K.; Hennig, Gayle E.; Horton, Robert A.; Roberts, Jeanette C.; Cohen, Steven D. . E-mail: scohen@mcp.edu

    2005-01-15

    Acetaminophen (APAP) nephrotoxicity has been observed both in humans and research animals. Recent studies suggest a contributory role for glutathione (GSH)-derived conjugates of APAP in the development of nephrotoxicity. Inhibitors of either {gamma}-glutamyl transpeptidase ({gamma}-GT) or the probenecid-sensitive organic anion transporter ameliorate APAP-induced nephrotoxicity but not hepatotoxicity in mice and inhibition of {gamma}-GT similarly protected rats from APAP nephrotoxicity. Protection against APAP nephrotoxicity by disruption of these GSH conjugate transport and metabolism pathways suggests that GSH conjugates are involved. APAP-induced renal injury may involve the acetaminophen-glutathione (APAP-GSH) conjugate or a metabolite derived from APAP-GSH. Acetaminophen-cysteine (APAP-CYS) is a likely candidate for involvement in APAP nephrotoxicity because it is both a product of the {gamma}-GT pathway and a probable substrate for the organic anion transporter. The present experiments demonstrated that APAP-CYS treatment alone depleted renal but not hepatic glutathione (GSH) in a dose-responsive manner. This depletion of renal GSH may predispose the kidney to APAP nephrotoxicity by diminishing GSH-mediated detoxification mechanisms. Indeed, pretreatment of male CD-1 mice with APAP-CYS before challenge with a threshold toxic dose of APAP resulted in significant enhancement of APAP-induced nephrotoxicity. This was evidenced by histopathology and plasma blood urea nitrogen (BUN) levels at 24 h after APAP challenge. APAP alone was minimally nephrotoxic and APAP-CYS alone produced no detectable injury. By contrast, APAP-CYS pretreatment did not alter the liver injury induced by APAP challenge. These data are consistent with there being a selective, contributory role for APAP-GSH-derived metabolites in APAP-induced renal injury that may involve renal-selective GSH depletion.

  17. Fennel and raspberry leaf as possible inhibitors of acetaminophen oxidation.

    PubMed

    Langhammer, Astrid Jordet; Nilsen, Odd Georg

    2014-10-01

    In addition to CYP2E1, several CYP isoenzymes, notably CYP1A2, 2D6, and 3A4, are suggested to contribute in acetaminophen oxidation and formation of the hepatotoxic metabolite N-acetyl-p-benzoquinone imine (NAPQI). The in vitro CYP2E1 inhibitory potentials of fennel and raspberry leaf, herbs previously found to inhibit CYP1A2, 2D6, and 3A4 activities in vitro, were investigated. Extracts from commercially available herbal products were incubated with recombinant cDNA-expressed human CYP2E1. A validated LC/MS/MS methodology was applied for determination of 6-hydroxychlorzoxazone formation with disulfiram used as a positive inhibitory control. CYP2E1 IC50 inhibition constants were found to be 23 ± 4 and 27 ± 5 µg/ml for fennel and raspberry leaf, respectively, constants significantly lower than those presented in the literature for other herbal extracts. Together with previous findings, the presented in vitro data for CYP2E1 inhibition suggest that fennel and raspberry leaf have a significant potential of inhibiting all the major metabolic pathways for acetaminophen oxidation and NAPQI formation. Both herbs should be further investigated for their in vivo ability of inhibiting acetaminophen oxidation and NAPQI formation.

  18. Quercitrin from Toona sinensis (Juss.) M.Roem. Attenuates Acetaminophen-Induced Acute Liver Toxicity in HepG2 Cells and Mice through Induction of Antioxidant Machinery and Inhibition of Inflammation

    PubMed Central

    Truong, Van-Long; Ko, Se-Yeon; Jun, Mira; Jeong, Woo-Sik

    2016-01-01

    Quercitrin is found in many kinds of vegetables and fruits, and possesses various bioactive properties. The aim of the present study was to elucidate hepatoprotective mechanisms of quercitrin isolated from Toona sinensis (Juss.) M.Roem. (syn. Cedrela sinensis Juss.), using acetaminophen (APAP)-treated HepG2 cell and animal models. In an in vitro study, quercitrin suppressed the production of reactive oxygen species and enhanced expression of nuclear factor E2-related factor 2 (Nrf2), activity of antioxidant response element (ARE)-reporter gene, and protein levels of NADPH: quinone oxidoreductase 1 (NQO1), catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase 2 (SOD-2) in APAP-treated HepG2 cells. In an in vivo study, Balb/c mice were orally administered with 10 or 50 mg/kg of quercitrin for 7 days and followed by the injection with single dose of 300 mg/kg APAP. Quercitrin decreased APAP-caused elevation of alanine aminotransferase and aspartate aminotransferase levels, liver necrosis, the expression of pro-inflammatory factors including inducible nitric oxide synthase, cyclooxygenase 2 and inerleukin-1β, and phosphorylation of kinases including c-Jun N-terminal kinase and p38. Quercitrin restored protein levels of Nrf2, NQO1 and activities and expressions of CAT, GPx, SOD-2. The results suggested that quercitrin attenuates APAP-induced liver damage by the activation of defensive genes and the inhibition of pro-inflammatory genes via the suppressions of JNK and p38 signaling. PMID:27428996

  19. Glucuronides from metabolites to medicines: a survey of the in vivo generation, chemical synthesis and properties of glucuronides.

    PubMed

    Stachulski, Andrew V; Meng, Xiaoli

    2013-06-01

    Covering: 1998 to 2011. Previous review: Nat. Prod. Rep., 1998, 15, 173-186. The fourteen years that have passed since the previous review on this topic have seen a significant increase of interest in many aspects of glucuronide chemistry and biology. Glucuronides are the most important class of phase 2 xenobiotic metabolites and typically act in a detoxifying role. While this is generally true for O-alkyl and O-aryl glucuronides, a number of glucuronides are known to be pharmacologically active per se. Additionally the use of glucuronide prodrugs, notably to ameliorate the cytotoxicity of anticancer agents, has markedly increased. Whereas the previous review covered only the synthesis of O-glucuronides, we now include N-, S- and C-glucuronides also and discuss both synthetic and biological aspects. Synthetic methods for all classes of glucuronides are reviewed and updated, together with advances in the enzymatic synthesis of glucuronides and methods for their detection. Finally we discuss the biological reactivity of glucuronides where known, including the important morphine-6-glucuronide. A lively debate has continued for several years on whether O-acyl glucuronide metabolites of carboxylic acids are toxic, affecting both the safety assessment of well-used drugs and new drug development programmes. We summarise the current understanding, together with other known examples of interaction between glucuronides and macromolecules.

  20. In silico prediction of acyl glucuronide reactivity

    NASA Astrophysics Data System (ADS)

    Potter, Tim; Lewis, Richard; Luker, Tim; Bonnert, Roger; Bernstein, Michael A.; Birkinshaw, Timothy N.; Thom, Stephen; Wenlock, Mark; Paine, Stuart

    2011-11-01

    Drugs and drug candidates containing a carboxylic acid moiety, including many widely used non-steroidal anti-inflammatory drugs (NSAIDs) are often metabolized to form acyl glucuronides (AGs). NSAIDs such as Ibuprofen are amongst the most widely used drugs on the market, whereas similar carboxylic acid drugs such as Suprofen have been withdrawn due to adverse events. Although the link between these AG metabolites and toxicity is not proven, there is circumstantial literature evidence to suggest that more reactive acyl glucuronides may, in some cases, present a greater risk of exhibiting toxic effects. We wished therefore to rank the reactivity of potential new carboxylate-containing drug candidates, and performed kinetic studies on synthetic acyl glucuronides to benchmark our key compounds. Driven by the desire to quickly rank the reactivity of compounds without the need for lengthy synthesis of the acyl glucuronide, a correlation was established between the degradation half-life of the acyl glucuronide and the half life for the hydrolysis of the more readily available methyl ester derivative. This finding enabled a considerable broadening of chemical property space to be investigated. The need for kinetic measurements was subsequently eliminated altogether by correlating the methyl ester hydrolysis half-life with the predicted 13C NMR chemical shift of the carbonyl carbon together with readily available steric descriptors in a PLS model. This completely in silico prediction of acyl glucuronide reactivity is applicable within the earliest stages of drug design with low cost and acceptable accuracy to guide intelligent molecular design. This reactivity data will be useful alongside the more complex additional pharmacokinetic exposure and distribution data that is generated later in the drug discovery process for assessing the overall toxicological risk of acidic drugs.

  1. Identification of Human UDP-Glucuronosyltransferase 1A4 as the Major Isozyme Responsible for the Glucuronidation of 20(S)-Protopanaxadiol in Human Liver Microsomes

    PubMed Central

    Li, Jia; He, Chunyong; Fang, Lianxiang; Yang, Li; Wang, Zhengtao

    2016-01-01

    20(S)-protopanaxadiol (PPD), one of the representative aglycones of ginsenosides, has a broad spectrum of pharmacological activities. Although phase I metabolism has been investigated extensively, information regarding phase II metabolism of this compound remains to be elucidated. Here, a glucuronidated metabolite of PPD in human liver microsomes (HLMs) and rat liver microsomes (RLMs) was unambiguously identified as PPD-3-O-β-d-glucuronide by nuclear magnetic resonance spectroscopy and high resolution mass spectrometry. The chemical inhibition and recombinant human UDP-Glucuronosyltransferase (UGT) isoforms assay showed that the PPD glucuronidation was mainly catalyzed by UGT1A4 in HLM, whereas UGT1A3 showed weak catalytic activity. In conclusion, PPD-3-O-β-d-glucuronide was first identified as the principal glucuronidation metabolite of PPD in HLMs, which was catalyzed by UGT1A4. PMID:27005621

  2. Intravenous paracetamol (acetaminophen).

    PubMed

    Duggan, Sean T; Scott, Lesley J

    2009-01-01

    Intravenous paracetamol (rINN)/intravenous acetaminophen (USAN) is an analgesic and antipyretic agent, recommended worldwide as a first-line agent for the treatment of pain and fever in adults and children. In double-blind clinical trials, single or multiple doses of intravenous paracetamol 1 g generally provided significantly better analgesic efficacy than placebo treatment (as determined by primary efficacy endpoints) in adult patients who had undergone dental, orthopaedic or gynaecological surgery. Furthermore, where evaluated, intravenous paracetamol 1 g generally showed similar analgesic efficacy to a bioequivalent dose of propacetamol, and a reduced need for opioid rescue medication. In paediatric surgical patients, recommended doses of intravenous paracetamol 15 mg/kg were not significantly different from propacetamol 30 mg/kg for the treatment of pain, and showed equivocal analgesic efficacy compared with intramuscular pethidine 1 mg/kg in several randomized, active comparator-controlled studies. In a randomized, noninferiority study in paediatric patients with an infection-induced fever, intravenous paracetamol 15 mg/kg treatment was shown to be no less effective than propacetamol 30 mg/kg in terms of antipyretic efficacy. Intravenous paracetamol was well tolerated in clinical trials, having a tolerability profile similar to placebo. Additionally, adverse reactions emerging from the use of the intravenous formulation of paracetamol are extremely rare (<1/10 000). [table: see text].

  3. Metabonomic analysis of Bombyx mori (Heterocera: Bombysidae) treated with acetaminophen.

    PubMed

    Yin, W M; Xu, X; He, Y; Wei, G B; Sima, Y H; Shi-Qing, Xu

    2014-01-01

    The feasibility of using Bombyx mori as model animal is attracting more attention. Whether the effect of drugs on the metabolite profiling was consistent with those in mammals was an aspect to evaluate the feasibility of B. mori as model animal. In this study, we used acetaminophen to treat Dazao fifth-instar B. mori, and its metabolites in hemolymph were detected by gas chromatography-mass spectrometry. The corresponding data were processed and analyzed by total model analysis, principal component analysis, partial least squares-discriminant analysis, orthogonal partial least squares-discriminant analysis, and finally, the difference metabolites between acetaminophen group and control group were selected and identified by our reference material database and the National Institute of Standard and Technology database. The results showed that acetaminophen administration induced elevation of metabolites related to energy source, the intermediate of cholesterol synthesis, and the metabolites related to melanization and also induced the decrease of metabolites in pathway of Krebs cycle, the cholesterol, and sitosterol, which suggested that acetaminophen administration inhibited energy metabolism and promoted the expenditure and imbalance of hormone and melanization.

  4. Transcriptomic studies on liver toxicity of acetaminophen.

    PubMed

    Toska, Endrit; Zagorsky, Robert; Figler, Bryan; Cheng, Feng

    2014-09-01

    Acetaminophen is widely used as a pain reliever and to reduce fever. At high doses, it can cause severe hepatotoxicity. Acetaminophen overdose has become the leading cause of acute liver failure in the US. The mechanisms for acetaminophen-induced liver injury are unclear. Transcriptomic studies can identify the changes in expression of thousands of genes when exposed to supratherapeutic doses of acetaminophen. These studies elucidated the mechanism of acetaminophen-induced hepatotoxicity and also provide insight into future development of diagnosis and treatment options for acetaminophen-induced acute liver failure. The following is a brief overview of some recent transcriptomic studies and gene-expression-based prediction models on liver toxicity induced by acetaminophen.

  5. Effect of Acetaminophen Ingestion on Thermoregulation of Normothermic, Non-febrile Humans.

    PubMed

    Foster, Josh; Mauger, Alexis; Thomasson, Katie; White, Stephanie; Taylor, Lee

    2016-01-01

    temperature, heart rate, or thermal sensation between the acetaminophen and placebo trials (p > 0.05). The results indicate oral acetaminophen reduces core temperature of humans exposed to an environment beneath the thermal neutral zone. These results suggest that acetaminophen may inhibit the thermogenic mechanisms required to regulate core temperature during exposure to sub-neutral environments.

  6. Comparison of Bile Acids and Acetaminophen Protein Adducts in Children and Adolescents with Acetaminophen Toxicity

    PubMed Central

    James, Laura; Yan, Ke; Pence, Lisa; Simpson, Pippa; Bhattacharyya, Sudeepa; Gill, Pritmohinder; Letzig, Lynda; Kearns, Gregory; Beger, Richard

    2015-01-01

    Metabolomics approaches have enabled the study of new mechanisms of liver injury in experimental models of drug toxicity. Disruption of bile acid homeostasis is a known mechanism of drug induced liver injury. The relationship of individual bile acids to indicators of oxidative drug metabolism (acetaminophen protein adducts) and liver injury was examined in children with acetaminophen overdose, hospitalized children with low dose exposure to acetaminophen, and children with no recent exposure to acetaminophen. Nine bile acids were quantified through targeted metabolomic analysis in the serum samples of the three groups. Bile acids were compared to serum levels of acetaminophen protein adducts and alanine aminotransferase. Glycodeoxycholic acid, taurodeoxycholic acid, and glycochenodeoxycholic acid were significantly increased in children with acetaminophen overdose compared to healthy controls. Among patients with acetaminophen overdose, bile acids were higher in subjects with acetaminophen protein adduct values > 1.0 nmol/mL and modest correlations were noted for three bile acids and acetaminophen protein adducts as follows: taurodeoxycholic acid (R=0.604; p<0.001), glycodeoxycholic acid (R=0.581; p<0.001), and glycochenodeoxycholic acid (R=0.571; p<0.001). Variability in bile acids was greater among hospitalized children receiving low doses of acetaminophen than in healthy children with no recent acetaminophen exposure. Compared to bile acids, acetaminophen protein adducts more accurately discriminated among children with acetaminophen overdose, children with low dose exposure to acetaminophen, and healthy control subjects. In children with acetaminophen overdose, elevations of conjugated bile acids were associated with specific indicators of acetaminophen metabolism and non-specific indicators of liver injury. PMID:26208104

  7. Comparison of Bile Acids and Acetaminophen Protein Adducts in Children and Adolescents with Acetaminophen Toxicity.

    PubMed

    James, Laura; Yan, Ke; Pence, Lisa; Simpson, Pippa; Bhattacharyya, Sudeepa; Gill, Pritmohinder; Letzig, Lynda; Kearns, Gregory; Beger, Richard

    2015-01-01

    Metabolomics approaches have enabled the study of new mechanisms of liver injury in experimental models of drug toxicity. Disruption of bile acid homeostasis is a known mechanism of drug induced liver injury. The relationship of individual bile acids to indicators of oxidative drug metabolism (acetaminophen protein adducts) and liver injury was examined in children with acetaminophen overdose, hospitalized children with low dose exposure to acetaminophen, and children with no recent exposure to acetaminophen. Nine bile acids were quantified through targeted metabolomic analysis in the serum samples of the three groups. Bile acids were compared to serum levels of acetaminophen protein adducts and alanine aminotransferase. Glycodeoxycholic acid, taurodeoxycholic acid, and glycochenodeoxycholic acid were significantly increased in children with acetaminophen overdose compared to healthy controls. Among patients with acetaminophen overdose, bile acids were higher in subjects with acetaminophen protein adduct values > 1.0 nmol/mL and modest correlations were noted for three bile acids and acetaminophen protein adducts as follows: taurodeoxycholic acid (R=0.604; p<0.001), glycodeoxycholic acid (R=0.581; p<0.001), and glycochenodeoxycholic acid (R=0.571; p<0.001). Variability in bile acids was greater among hospitalized children receiving low doses of acetaminophen than in healthy children with no recent acetaminophen exposure. Compared to bile acids, acetaminophen protein adducts more accurately discriminated among children with acetaminophen overdose, children with low dose exposure to acetaminophen, and healthy control subjects. In children with acetaminophen overdose, elevations of conjugated bile acids were associated with specific indicators of acetaminophen metabolism and non-specific indicators of liver injury.

  8. 2D QSAR Study for Gemfibrozil Glucuronide as the Mechanism-based Inhibitor of CYP2C8

    PubMed Central

    Taxak, N.; Bharatam, P. V.

    2013-01-01

    Mechanism-based inhibition of cytochrome P450 involves the bioactivation of the drug to a reactive metabolite, which leads to cytochrome inhibition via various mechanisms. This is generally seen in the Phase I of drug metabolism. However, gemfibrozil (hypolipidemic drug) leads to mechanism-based inhibition after generating glucuronide conjugate (gemfibrozil acyl-β-glucuronide) in the Phase II metabolism reaction. The mechanism involves the covalent binding of the benzyl radical (generated from the oxidation of aromatic methyl group in conjugate) to the heme of CYP2C8. This article deals with the development of a 2D QSAR model based on the inhibitory potential of gemfibrozil, its analogues and corresponding glucuronide conjugates in inhibiting the CYP2C8-catalysed amodiaquine N-deethylation. The 2D QSAR model was developed using multiple linear regression analysis in Accelrys Discovery Studio 2.5 and helps in identifying the descriptors, which are actually contributing to the inhibitory potency of the molecules studied. The built model was further validated using leave one out method. The best quantitative structure activity relationship model was selected having a correlation coefficient (r) of 0.814 and cross-validated correlation coefficient (q2) of 0.799. 2D QSAR revealed the importance of volume descriptor (Mor15v), shape descriptor (SP09) and 3D matrix-based descriptor (SpMax_RG) in defining the activity for this series of molecules. It was observed that volume and 3D matrix-based descriptors were crucial in imparting higher potency to gemfibrozil glucuronide conjugate, as compared with other molecules. The results obtained from the present study may be useful in predicting the inhibitory potential (IC50 for CYP2C8 inhibition) of the glucuronide conjugates of new molecules and compare with the standard gemfibrozil acyl-β-glucuronide (in terms of pIC50 values) in early stages of drug discovery and development. PMID:24591743

  9. Glucuronidation of Dihydrotestosterone and trans-Androsterone by Recombinant UDP-Glucuronosyltransferase (UGT) 1A4: Evidence for Multiple UGT1A4 Aglycone Binding Sites

    PubMed Central

    Zhou, Jin; Tracy, Timothy S.

    2010-01-01

    UDP-glucuronosyltransferase (UGT) 1A4-catalyzed glucuronidation is an important drug elimination pathway. Although atypical kinetic profiles (nonhyperbolic, non-Michaelis-Menten) of UGT1A4-catalyzed glucuronidation have been reported occasionally, systematic kinetic studies to explore the existence of multiple aglycone binding sites in UGT1A4 have not been conducted. To this end, two positional isomers, dihydrotestosterone (DHT) and trans-androsterone (t-AND), were used as probe substrates, and their glucuronidation kinetics with HEK293-expressed UGT1A4 were evaluated both alone and in the presence of a UGT1A4 substrate [tamoxifen (TAM) or lamotrigine (LTG)]. Coincubation with TAM, a high-affinity UGT1A4 substrate, resulted in a concentration-dependent activation/inhibition effect on DHT and t-AND glucuronidation, whereas LTG, a low-affinity UGT1A4 substrate, noncompetitively inhibited both processes. The glucuronidation kinetics of TAM were then evaluated both alone and in the presence of different concentrations of DHT or t-AND. TAM displayed substrate inhibition kinetics, suggesting that TAM may have two binding sites in UGT1A4. However, the substrate inhibition kinetic profile of TAM became more hyperbolic as the DHT or t-AND concentration was increased. Various two-site kinetic models adequately explained the interactions between TAM and DHT or TAM and t-AND. In addition, the effect of TAM on LTG glucuronidation was evaluated. In contrast to the mixed effect of TAM on DHT and t-AND glucuronidation, TAM inhibited LTG glucuronidation. Our results suggest that multiple aglycone binding sites exist within UGT1A4, which may result in atypical kinetics (both homotropic and heterotropic) in a substrate-dependent fashion. PMID:20007295

  10. Glucuronidation of dihydrotestosterone and trans-androsterone by recombinant UDP-glucuronosyltransferase (UGT) 1A4: evidence for multiple UGT1A4 aglycone binding sites.

    PubMed

    Zhou, Jin; Tracy, Timothy S; Remmel, Rory P

    2010-03-01

    UDP-glucuronosyltransferase (UGT) 1A4-catalyzed glucuronidation is an important drug elimination pathway. Although atypical kinetic profiles (nonhyperbolic, non-Michaelis-Menten) of UGT1A4-catalyzed glucuronidation have been reported occasionally, systematic kinetic studies to explore the existence of multiple aglycone binding sites in UGT1A4 have not been conducted. To this end, two positional isomers, dihydrotestosterone (DHT) and trans-androsterone (t-AND), were used as probe substrates, and their glucuronidation kinetics with HEK293-expressed UGT1A4 were evaluated both alone and in the presence of a UGT1A4 substrate [tamoxifen (TAM) or lamotrigine (LTG)]. Coincubation with TAM, a high-affinity UGT1A4 substrate, resulted in a concentration-dependent activation/inhibition effect on DHT and t-AND glucuronidation, whereas LTG, a low-affinity UGT1A4 substrate, noncompetitively inhibited both processes. The glucuronidation kinetics of TAM were then evaluated both alone and in the presence of different concentrations of DHT or t-AND. TAM displayed substrate inhibition kinetics, suggesting that TAM may have two binding sites in UGT1A4. However, the substrate inhibition kinetic profile of TAM became more hyperbolic as the DHT or t-AND concentration was increased. Various two-site kinetic models adequately explained the interactions between TAM and DHT or TAM and t-AND. In addition, the effect of TAM on LTG glucuronidation was evaluated. In contrast to the mixed effect of TAM on DHT and t-AND glucuronidation, TAM inhibited LTG glucuronidation. Our results suggest that multiple aglycone binding sites exist within UGT1A4, which may result in atypical kinetics (both homotropic and heterotropic) in a substrate-dependent fashion.

  11. Cannabinoid receptor-mediated antinociception with acetaminophen drug combinations in rats with neuropathic spinal cord injury pain

    PubMed Central

    Hama, Aldric T.; Sagen, Jacqueline

    2010-01-01

    Pre-clinical evidence demonstrates that neuropathic spinal cord injury (SCI) pain is maintained by a number of neurobiological mechanisms, suggesting that treatments directed at several pain-related targets may be more advantageous compared to a treatment focused on a single target. The current study evaluated the efficacy of the non-opiate analgesic acetaminophen, which has several putative analgesic mechanisms, combined with analgesic drugs used to treat neuropathic pain in a rat model of below-level neuropathic SCI pain. Following an acute compression of the mid-thoracic spinal cord, rats exhibited robust hind paw hypersensitivity to innocuous mechanical stimulation. Fifty percent antinociceptive doses of gabapentin, morphine, tramadol or memantine were combined with an ineffective dose of acetaminophen; acetaminophen alone was not antinociceptive. The combination of acetaminophen with either tramadol or memantine resulted in an additive antinociceptive effect. Acetaminophen combined with either morphine or gabapentin, however, resulted in supra-additive (synergistic) efficacy. One of the analgesic mechanisms of acetaminophen is inhibiting the uptake of endocannabinoids from the extracellular space. Pre-treatment with AM251, a cannabinoid receptor subtype-1 (CB1) antagonist, significantly diminished the antinociceptive effect of the acetaminophen+gabapentin combination. Pre-treatment with AM630, a cannabinoid receptor subtype-2 (CB2) antagonist, did not have an effect on this combination. By contrast, both AM251 and AM630 reduced the efficacy of the acetaminophen+morphine combination. None of the active drugs alone were affected by either CB receptor antagonist. The results imply that modulation of the endocannabinoid system in addition to other mechanisms mediate the synergistic antinociceptive effects of acetaminophen combinations. Despite the presence of a cannabinoid mechanism, synergism was not present in all acetaminophen combinations. The combination of

  12. Acyl glucuronides: the good, the bad and the ugly.

    PubMed

    Regan, Sophie L; Maggs, James L; Hammond, Thomas G; Lambert, Craig; Williams, Dominic P; Park, B Kevin

    2010-10-01

    Acyl glucuronidation is the major metabolic conjugation reaction of most carboxylic acid drugs in mammals. The physiological consequences of this biotransformation have been investigated incompletely but include effects on drug metabolism, protein binding, distribution and clearance that impact upon pharmacological and toxicological outcomes. In marked contrast, the exceptional but widely disparate chemical reactivity of acyl glucuronides has attracted far greater attention. Specifically, the complex transacylation and glycation reactions with proteins have provoked much inconclusive debate over the safety of drugs metabolised to acyl glucuronides. It has been hypothesised that these covalent modifications could initiate idiosyncratic adverse drug reactions. However, despite a large body of in vitro data on the reactions of acyl glucuronides with protein, evidence for adduct formation from acyl glucuronides in vivo is limited and potentially ambiguous. The causal connection of protein adduction to adverse drug reactions remains uncertain. This review has assessed the intrinsic reactivity, metabolic stability and pharmacokinetic properties of acyl glucuronides in the context of physiological, pharmacological and toxicological perspectives. Although numerous experiments have characterised the reactions of acyl glucuronides with proteins, these might be attenuated substantially in vivo by rapid clearance of the conjugates. Consequently, to delineate a relationship between acyl glucuronide formation and toxicological phenomena, detailed pharmacokinetic analysis of systemic exposure to the acyl glucuronide should be undertaken adjacent to determining protein adduct concentrations in vivo. Further investigation is required to ascertain whether acyl glucuronide clearance is sufficient to prevent covalent modification of endogenous proteins and consequentially a potential immunological response.

  13. Aspirin and acetaminophen: should they be available over the counter?

    PubMed

    Brune, Kay; Hinz, Burkhard; Otterness, Ivan

    2009-02-01

    Traditional nonsteroidal anti-inflammatory drugs block cyclooxygenase (COX). They are the most widely used drugs for pain relief. They are indispensable for their effects but are condemned for their adverse drug reactions. Two COX inhibitors, acetaminophen and aspirin, are the most widely used over-the-counter drugs. They have low (but useful) therapeutic activity, but they are endowed with specific risks that are not seen with most other COX inhibitors. Both are lethal if taken in overdose. Each is stigmatized by severe adverse effects. Aspirin results in prolonged inhibition of blood coagulation, and acetaminophen can result in liver toxicity at normal dose and liver failure at higher dose. Both drugs cause many deaths every year. We recommend that the status of both drugs be changed to prescription only. Their continued availability over the counter poses an unacceptable risk to the general population.

  14. A highly toxic morphine-3-glucuronide derivative.

    PubMed

    Salvatella, Mariona; Arsequell, Gemma; Valencia, Gregorio; Rodríguez, Raquel E

    2004-02-23

    By the coupling of octylamine to the uronic acid function of morphine-3-glucuronide (M3G) a new glycoconjugate (morphine-3-octylglucuronamide, M3GOAM) was prepared. When assayed in both rats and mice up to ng/kg (i.p.) doses none of the animals survived. The aliphatic octyl chain may be the lethal factor since a closely related derivative (M3GNH2), was not toxic and showed similar opioid antagonist properties than naloxone.

  15. Comparison of inhibitory effects between acetaminophen-glutathione conjugate and reduced glutathione in human glutathione reductase.

    PubMed

    Nýdlová, Erika; Vrbová, Martina; Cesla, Petr; Jankovičová, Barbora; Ventura, Karel; Roušar, Tomáš

    2014-09-01

    Acetaminophen overdose is the most frequent cause of acute liver injury. The main mechanism of acetaminophen toxicity has been attributed to oxidation of acetaminophen. The oxidation product is very reactive and reacts with glutathione generating acetaminophen-glutathione conjugate (APAP-SG). Although this conjugate has been recognized to be generally nontoxic, we have found recently that APAP-SG could produce a toxic effect. Therefore, the aim of our study was to estimate the toxicity of purified APAP-SG by characterizing the inhibitory effect in human glutathione reductase (GR) and comparing that to the inhibitory effect of the natural inhibitor reduced glutathione. We used two types of human GR: recombinant and freshly purified from red blood cells. Our results show that GR was significantly inhibited in the presence of both APAP-SG and reduced glutathione. For example, the enzyme activity of recombinant and purified GR was reduced in the presence of 4 mm APAP-SG (with 0.5 mm glutathione disulfide) by 28% and 22%, respectively. The type of enzyme inhibition was observed to be competitive in the cases of both APAP-SG and glutathione. As glutathione inhibits GR activity in cells under physiological conditions, the rate of enzyme inhibition ought to be weaker in the case of glutathione depletion that is typical of acetaminophen overdose. Notably, however, enzyme activity likely remains inhibited due to the presence of APAP-SG, which might enhance the pro-oxidative status in the cell. We conclude that our finding could reflect some other pathological mechanism that may contribute to the toxicity of acetaminophen.

  16. Acetaminophen-induced hepatotoxicity in mice is dependent on Tlr9 and the Nalp3 inflammasome.

    PubMed

    Imaeda, Avlin B; Watanabe, Azuma; Sohail, Muhammad A; Mahmood, Shamail; Mohamadnejad, Mehdi; Sutterwala, Fayyaz S; Flavell, Richard A; Mehal, Wajahat Z

    2009-02-01

    Hepatocyte death results in a sterile inflammatory response that amplifies the initial insult and increases overall tissue injury. One important example of this type of injury is acetaminophen-induced liver injury, in which the initial toxic injury is followed by innate immune activation. Using mice deficient in Tlr9 and the inflammasome components Nalp3 (NACHT, LRR, and pyrin domain-containing protein 3), ASC (apoptosis-associated speck-like protein containing a CARD), and caspase-1, we have identified a nonredundant role for Tlr9 and the Nalp3 inflammasome in acetaminophen-induced liver injury. We have shown that acetaminophen treatment results in hepatocyte death and that free DNA released from apoptotic hepatocytes activates Tlr9. This triggers a signaling cascade that increases transcription of the genes encoding pro-IL-1beta and pro-IL-18 in sinusoidal endothelial cells. By activating caspase-1, the enzyme responsible for generating mature IL-1beta and IL-18 from pro-IL-1beta and pro-IL-18, respectively, the Nalp3 inflammasome plays a crucial role in the second step of proinflammatory cytokine activation following acetaminophen-induced liver injury. Tlr9 antagonists and aspirin reduced mortality from acetaminophen hepatotoxicity. The protective effect of aspirin on acetaminophen-induced liver injury was due to downregulation of proinflammatory cytokines, rather than inhibition of platelet degranulation or COX-1 inhibition. In summary, we have identified a 2-signal requirement (Tlr9 and the Nalp3 inflammasome) for acetaminophen-induced hepatotoxicity and some potential therapeutic approaches.

  17. Cooperativity in CYP2E1 metabolism of acetaminophen and styrene mixtures.

    PubMed

    Hartman, Jessica H; Letzig, Lynda G; Roberts, Dean W; James, Laura P; Fifer, E Kim; Miller, Grover P

    2015-10-01

    Risk assessment for exposure to mixtures of drugs and pollutants relies heavily on in vitro characterization of their bioactivation and/or metabolism individually and extrapolation to mixtures assuming no interaction. Herein, we demonstrated that in vitro CYP2E1 metabolic activation of acetaminophen and styrene mixtures could not be explained through the Michaelis-Menten mechanism or any models relying on that premise. As a baseline for mixture studies with styrene, steady-state analysis of acetaminophen oxidation revealed a biphasic kinetic profile that was best described by negative cooperativity (Hill coefficient=0.72). The best-fit mechanism for this relationship involved two binding sites with differing affinities (Ks=830μM and Kss=32mM). Introduction of styrene inhibited that reaction less than predicted by simple competition and thus provided evidence for a cooperative mechanism within the mixture. Likewise, acetaminophen acted through a mixed-type inhibition mechanism to impact styrene epoxidation. In this case, acetaminophen competed with styrene for CYP2E1 (Ki=830μM and Ksi=180μM for catalytic and effector sites, respectively) and resulted in cooperative impacts on binding and catalysis. Based on modeling of in vivo clearance, cooperative interactions between acetaminophen and styrene resulted in profoundly increased styrene activation at low styrene exposure levels and therapeutic acetaminophen levels. Current Michaelis-Menten based toxicological models for mixtures such as styrene and acetaminophen would fail to detect this concentration-dependent relationship. Hence, future studies must assess the role of alternate CYP2E1 mechanisms in bioactivation of compounds to improve the accuracy of interpretations and predictions of toxicity.

  18. Acetaminophen use and asthma in children

    PubMed Central

    Sakulchit, Teeranai; Goldman, Ran D.

    2017-01-01

    Abstract Question A child with a history of asthma came to my clinic with acute fever. I have heard that acetaminophen might be associated with exacerbation of asthma. Is it safe if I recommend acetaminophen for this child? Answer Most studies suggest an association between acetaminophen use in children and development of asthma later in childhood. However, several confounding factors in study design might contribute to this positive correlation, and without a prospective controlled trial, confirming this finding is challenging. If children have a known history of asthma, it is likely safe to administer a single dose of acetaminophen without concern of precipitating adverse respiratory symptoms. Regular use of acetaminophen to relieve fever or pain does not seem to exacerbate asthma in children more than ibuprofen does. PMID:28292797

  19. Acetaminophen use and asthma in children.

    PubMed

    Sakulchit, Teeranai; Goldman, Ran D

    2017-03-01

    Question A child with a history of asthma came to my clinic with acute fever. I have heard that acetaminophen might be associated with exacerbation of asthma. Is it safe if I recommend acetaminophen for this child? Answer Most studies suggest an association between acetaminophen use in children and development of asthma later in childhood. However, several confounding factors in study design might contribute to this positive correlation, and without a prospective controlled trial, confirming this finding is challenging. If children have a known history of asthma, it is likely safe to administer a single dose of acetaminophen without concern of precipitating adverse respiratory symptoms. Regular use of acetaminophen to relieve fever or pain does not seem to exacerbate asthma in children more than ibuprofen does.

  20. Protective effect of pioglitazone, a PPARγ agonist against acetaminophen-induced hepatotoxicity in rats.

    PubMed

    Gupta, Gaurav; Krishna, Gopala; Chellappan, Dinesh Kumar; Gubbiyappa, Kumar Shiva; Candasamy, Mayuren; Dua, Kamal

    2014-08-01

    Acetaminophen has a reasonable safety profile when consumed in therapeutic doses. However, it could induce hepatotoxicity and even acute liver failure when taken at an overdose. Pioglitazone, PPARγ ligand, is clinically tested and used in treatment of diabetes. PPARγ is a key nuclear hormone receptor of lipid metabolisms and regulates several gene transcriptions associated with differentiation, growth arrest, and apoptosis. The aim of our study was to evaluate the hepatoprotective activity of pioglitazone on acetaminophen-induced hepatotoxicity and to understand the relationship between the PPARγ and acetaminophen-induced hepato injury. For the experiment, Sprague-Dawley rats (160-180 g) were used and divided into four groups. Groups I and II were normal and experimental controls, respectively. Groups III and IV received the pioglitazone 20 mg/kg for 10 days. Hepatotoxicity was induced in Groups II and III on the eighth day with acetaminophen (i.p. 350 mg/kg body weight). The hepatoprotective effect was evaluated by performing an assay of the total protein, total bilirubin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and α-fetoprotein as well as glutathione peroxidase, lipid peroxidation, catalase, superoxide dismutase, and glutathione transferase and liver histopathology. The assay results were presented as mean and standard error of mean for each group. The study group was compared with the control group by one-way ANOVA test. A p value of <0.05 was considered significant. Pioglitazone significantly reduced the elevated level of above serum marker enzymes and also inhibits the free radical formation by scavenging hydroxyl ions. It also restored the level of LPO and significantly elevated the levels of endogenous antioxidant enzymes in acetaminophen-challenged hepatotoxicity. Liver histopathological examination showed that pioglitazone administration antagonized acetaminophen -induced liver pathological damage. Various

  1. Understanding lactic acidosis in paracetamol (acetaminophen) poisoning.

    PubMed

    Shah, Anoop D; Wood, David M; Dargan, Paul I

    2011-01-01

    Paracetamol (acetaminophen) is one of the most commonly taken drugs in overdose in many areas of the world, and the most common cause of acute liver failure in both the UK and USA. Paracetamol poisoning can result in lactic acidosis in two different scenarios. First, early in the course of poisoning and before the onset of hepatotoxicity in patients with massive ingestion; a lactic acidosis is usually associated with coma. Experimental evidence from studies in whole animals, perfused liver slices and cell cultures has shown that the toxic metabolite of paracetamol, N-acetyl-p-benzo-quinone imine, inhibits electron transfer in the mitochondrial respiratory chain and thus inhibits aerobic respiration. This occurs only at very high concentrations of paracetamol, and precedes cellular injury by several hours. The second scenario in which lactic acidosis can occur is later in the course of paracetamol poisoning as a consequence of established liver failure. In these patients lactate is elevated primarily because of reduced hepatic clearance, but in shocked patients there may also be a contribution of peripheral anaerobic respiration because of tissue hypoperfusion. In patients admitted to a liver unit with paracetamol hepatotoxicity, the post-resuscitation arterial lactate concentration has been shown to be a strong predictor of mortality, and is included in the modified King's College criteria for consideration of liver transplantation. We would therefore recommend that post-resuscitation lactate is measured in all patients with a severe paracetamol overdose resulting in either reduced conscious level or hepatic failure.

  2. Intestinal first-pass glucuronidation activities of selected dihydroxyflavones.

    PubMed

    Wong, Yin Cheong; Zhang, Li; Lin, Ge; Zuo, Zhong

    2009-01-21

    Flavonoids have low bioavailabilities due to extensive intestinal first-pass metabolisms, especially glucuronidation. The present study aimed to evaluate the intestinal glucuronidation of dihydroxyflavones and provide more information on their structure-activity relationships. Seven dihydroxyflavones, namely 3,7-, 5,7-, 6,7-, 7,8-, 2',7-, 3',7-, and 4',7-dihydroxyflavone and a monohydroxyflavone, 7-hydroxyflavone, were investigated by incubating each hydroxyflavone at various concentrations with either human jejunum microsome or rat intestinal microsome. Two mono-glucuronides were identified for each dihydroxyflavone. For human jejunum microsome, most of the studied dihydroxyflavones demonstrated greater glucuronidation activities than that of 7-hydroxyflavone except for 3,7-dihydroxyflavone and 4',7-dihydroxyflavone. 3',7-dihydroxyflavone had the greatest intrinsic clearance which was at least seven times greater than that of all other dihydroxyflavones. In addition, species difference in glucuronidation activity was observed with human jejunum microsome higher than rat intestinal microsome for all hydroxyflavones except for 3,7-dihydroxyflavone. The results further demonstrated that the hydroxyl group positions do affect the intestinal glucuronidation activity of hydroxyflavones. Increasing the number of hydroxyl groups on A- or B-ring (except for 4'-OH) would enhance the glucuronidation activity of flavones, whereas adding a 3-OH on C-ring might not. Furthermore, existence of hydroxyl group at 3' position may enhance the glucuronidation activity of flavonoids.

  3. Glucuronidation, a new metabolic pathway for pyrrolizidine alkaloids.

    PubMed

    He, Yu-Qi; Yang, Li; Liu, Hui-Xin; Zhang, Jiang-Wei; Liu, Yong; Fong, Alan; Xiong, Ai-Zhen; Lu, Yan-Liu; Yang, Ling; Wang, Chang-Hong; Wang, Zheng-Tao

    2010-03-15

    Pyrrolizidine alkaloids (PAs) possess significant hepatotoxicity to humans and animals after metabolic activation by liver P450 enzymes. Metabolism pathways of PAs have been studied for several decades, including metabolic activation, hydroxylation, N-oxidation, and hydrolysis. However, the glucuronidation of intact PAs has not been investigated, although glucuronidation plays an important role in the elimination and detoxication of xenobiotics. In this study, PAs glucuronidation was investigated, and three important points were found. First, we demonstrated that senecionine (SEN)-a representative hepatotoxic PA-could be conjugated by glucuronic acid via an N-glucuronidation reaction catalyzed by uridine diphosphate glucuronosyl transferase in human liver microsomes. Second, glucuronidation of SEN was catalyzed not only by human but also other animal species and showed significant species differences. Rabbits, cattle, sheep, pigs, and humans showed the significantly higher glucuronidation activity than mice, rats, dogs, and guinea pigs on SEN. Kinetics of SEN glucuronidation in humans, pigs, and rabbits followed the one-site binding model of the Michaelis-Menten equation, while cattle and sheep followed the two-sites binding model of the Michaelis-Menten equation. Third, besides SEN, other hepatotoxic PAs including monocrotaline, adonifoline, and isoline also underwent N-glucuronidation in humans and several animal species such as rabbits, cattle, sheep, and pigs.

  4. 17β-Estradiol protects against acetaminophen-overdose-induced acute oxidative hepatic damage and increases the survival rate in mice.

    PubMed

    Chandrasekaran, Victor Raj Mohan; Periasamy, Srinivasan; Liu, Li-Lian; Liu, Ming-Yie

    2011-01-01

    Acetaminophen overdose causes acute liver injury or even death in both humans and experimental animals. We investigated the effect of 17β-estradiol against acetaminophen-induced acute liver injury and mortality in mice. Male mice were given acetaminophen (p-acetamidophenol; 300 mg/kg; orally) to induce acute liver injury. Acetaminophen significantly increased the levels of aspartate transaminase, alanine transaminase, myeloperoxidase, lipid peroxidation, and glutathione reductase, but it decreased superoxide dismutase, catalase, and glutathione. In addition, acetaminophen-induced mortality began 4h post-treatment, and all mice died within 9h. 17β-Estradiol (200 μg/kg; i.p.) protected against acetaminophen-induced oxidative hepatic damage by inhibiting neutrophil infiltration and stimulating the antioxidant defense system. However, 17β-estradiol did not affect acetaminophen-induced glutathione depletion or increased glutathione reductase activity. We conclude that 17β-estradiol specifically attenuates acute hepatic damage and decreases mortality in acetaminophen-overdosed male mice.

  5. Satkara (Citrus macroptera) Fruit Protects against Acetaminophen-Induced Hepatorenal Toxicity in Rats

    PubMed Central

    Paul, Sudip; Islam, Md. Aminul; Tanvir, E. M.; Ahmed, Romana; Das, Sagarika; Rumpa, Nur-E-Noushin; Hossen, Md. Sakib; Parvez, Mashud; Gan, Siew Hua; Khalil, Md. Ibrahim

    2016-01-01

    Although Citrus macroptera (Rutaceae), an indigenous fruit in Bangladesh, has long been used in folk medicine, however, there is a lack of information concerning its protective effects against oxidative damage. The protective effects of an ethanol extract of Citrus macroptera (EECM) against acetaminophen-induced hepatotoxicity and nephrotoxicity were investigated in rats. Rats (treatment groups) were pretreated with EECM at doses of 250, 500, and 1000 mg/kg, respectively, orally for 30 days followed by acetaminophen administration. Silymarin (100 mg/kg) was administered as a standard drug over a similar treatment period. Our findings indicated that oral administration of acetaminophen induced severe hepatic and renal injuries associated with oxidative stress, as observed by 2-fold higher lipid peroxidation (TBARS) compared to control. Pretreatment with EECM prior to acetaminophen administration significantly improved all investigated biochemical parameters, that is, transaminase activities, alkaline phosphatase, lactate dehydrogenase, γ-glutamyl transferase activities and total bilirubin, total cholesterol, triglyceride and creatinine, urea, uric acid, sodium, potassium and chloride ions, and TBARS levels. These findings were confirmed by histopathological examinations. The improvement was prominent in the group that received 1000 mg/kg EECM. These findings suggested that C. macroptera fruit could protect against acetaminophen-induced hepatonephrotoxicity, which might be via the inhibition of lipid peroxidation. PMID:27034701

  6. The Social Side Effects of Acetaminophen

    NASA Astrophysics Data System (ADS)

    Mischkowski, Dominik

    About 23% of all adults in the US take acetaminophen during an average week (Kaufman, Kelly, Rosenberg, Anderson, & Mitchell, 2002) because acetaminophen is an effective physical painkiller and easily accessible over the counter. The physiological side effects of acetaminophen are well documented and generally mild when acetaminophen is consumed in the appropriate dosage. In contrast, the psychological and social side effects of acetaminophen are largely unknown. Recent functional neuroimaging research suggests that the experience of physical pain is fundamentally related to the experience of empathy for the pain of other people, indicating that pharmacologically reducing responsiveness to physical pain also reduces cognitive, affective, and behavioral responsiveness to the pain of others. I tested this hypothesis across three double-blind between-subjects drug intervention studies. Two experiments showed that acetaminophen had moderate effects on empathic affect, specifically personal distress and empathic concern, and a small effect on empathic cognition, specifically perceived pain, when facing physical and social pain of others. The same two experiments and a third experiment also showed that acetaminophen can increase the willingness to inflict pain on other people, i.e., actual aggressive behavior. This effect was especially pronounced among people low in dispositional empathic concern. Together, these findings suggest that the physical pain system is more involved in the regulation of social cognition, affect, and behavior than previously assumed and that the experience of physical pain and responsiveness to the pain of others share a common neurochemical basis. Furthermore, these findings suggest that acetaminophen has unappreciated but serious social side effects, and that these side effects may depend on psychological characteristics of the drug consumer. This idea is consistent with recent theory and research on the context-dependency of neurochemical

  7. Acetaminophen toxicity with concomitant use of carbamazepine.

    PubMed

    Jickling, Glen; Heino, Angela; Ahmed, S Nizam

    2009-12-01

    Acetaminophen is a widely used analgesic that can cause acute liver failure when consumed above a maximum daily dose. Certain patients may be at increased risk of hepatocellular damage even at conventional therapeutic doses. We report a case of a 34-year-old man on carbamazepine for complex partial seizures who developed acute liver and renal failure on less than 2.5 grams a day of acetaminophen. This raises caution that patients on carbamazepine should avoid chronic use of acetaminophen, and if required use at lower doses with vigilant monitoring for signs of liver damage.

  8. A specific immunoassay for the determination of morphine and its glucuronides in human blood.

    PubMed

    Beike, J; Blaschke, G; Mertz, A; Köhler, H; Brinkmann, B

    1998-01-01

    The development of specific antisera for immunochemical determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide is described. Morphine was N-demethylated to normorphine and N-alkylated to give N-aminopropyl-normorphine as hapten for antisera against morphine. As haptens for antisera against morphine-3-glucuronide and morphine-6-glucuronide, N-aminopropyl-nor-morphine was glucuronidated in position 3 or 6 respectively. Each of these three haptens were coupled to BSA employing the glutaraldehyde method to obtain three different immunogens. Immunisation of rabbits with these conjugates gave anti-morphine, anti-morphine-3-glucuronide and anti-morphine-6-glucuronide antisera, which were tested in a competitive, heterogeneous radioimmunoassay. Tracers for this radioimmunoassay procedure were synthesised by substitution of morphine and morphine-6-glucuronide in position 2 with 125I and indirect iodination of the morphine-3-glucuronide hapten according to the method of Bolton and Hunter. The resulting antisera show very specific reactions with morphine, morphine-3-glucuronide and morphine-6-glucuronide. Cross reactivities of each antiserum with structurally related opiates and opioides are very low. The cross reactivities of the anti-morphine antiserum against morphine-3-glucuronide, morphine-6-glucuronide, codeine, codeine-6-glucuronide or dihydrocodeine were less than 0.3%, the anti-morphine-3-glucuronide antiserum against morphine, morphine-6-glucuronide, codeine, codeine-6-glucuronide or dihydrocodeine less than 0.1% and the anti-morphine-6-glucuronide antiserum against morphine, morphine-3-glucuronide, codeine or dihydrocodeine less than 0.1%, against codeine-6-glucuronide less than 2.3%. The determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide in blood samples (limit of detection= 3, 1, 0.5 ng/g) of nine cases of fatal heroin overdose with this radioimmunoassay method and the comparison with a GC/MS method is described.

  9. Structure-activity relationship (SAR): effort towards blocking N-glucuronidation of indazoles (PF-03376056) by human UGT1A enzymes.

    PubMed

    Rose, Kelly; Yang, Young-Sun; Sciotti, Richard; Cai, Hongliang

    2009-01-01

    GyrATPase is a cellular enzyme that has been used as an antibacterial target for treatment of nosocomial and community acquired bacterial infections. The leading chemical series targeted at inhibiting this enzyme, indazoles, were rapidly cleared in rats (CL > 70 mL/min/kg). The predominant metabolite identified in both urine and bile samples from a bile duct-cannulated study corresponded to direct glucuronidation of the parent compound and was excreted rapidly. Subsequently, a carefully designed analog was used to pinpoint the site of glucuronidation (N-glucuronidation) by incubation with rat hepatocytes and followed by mass spectrometry analysis. Reaction mapping with an array of recombinant UGT isozymes revealed that N-glucuronidation was predominantly catalyzed by the UGT1A family of enzymes. Based on the results, the following approaches were considered to reduce or eliminate glucuronidation: 1) adding sterically hindered substitutions on the phenyl ring of the indazole core; 2) changing the electron distribution by substituting with electron-donating or -withdrawing groups; 3) replacing the site of glucuronidation. The resulted compounds were evaluated in vitro in rat hepatocytes to assess their metabolic stabilities followed by in vivo efficacy studies in the murine peritonitis sepsis model (at 50 mg/kg) for selected compounds.

  10. Glucuronidation in the polar bear (Ursus maritimus).

    PubMed

    Sacco, James C; James, Margaret O

    2004-01-01

    Polar bears bioaccumulate lipophilic pollutants, including polychlorinated biphenyls (PCBs), into their bodies from their exclusive diet of marine organisms. Hydroxylated PCB metabolites (OH-PCBs) have been found in plasma, presumably due to CYP-dependent biotransformation of PCBs in liver. Little is known about the phase 2 metabolism of hydroxylated xenobiotics in polar bears. The objective of this study was to examine UDP-glucuronosyltransferase (UGT) activity with OH-PCBs and a hydroxylated polycyclic aromatic hydrocarbon, 3-hydroxy-benzo(a)pyrene (3-OH-BaP), in polar bear liver. Samples of frozen polar bear liver were used to prepare microsomes. UGT activity with 3-OH-BaP in Brij-treated microsomes, measured by a fluorescence assay, was readily measurable with protein concentrations in assay tubes of up to 10 g/ml, but dropped off very sharply at higher protein concentrations. The apparent Km for 3-OH-BaP was 1.71 +/- 0.04 microM, and Vmax 1.26 +/- 0.16 nmol/min/mg protein (mean +/- SD, n=3). UGT activities with a model tetrachloro-OH-PCB (4'-OH-CB72) and a model hexachloro-OH-PCB (4'-OH-CB159) were assayed with [14-C]-UDPGA and separation of the [14-C]-glucuronide by ion-pair extraction and thin-layer chromatography. [14-C]-glucuronide conjugates were readily formed by polar bear liver microsomes in the absence of added substrate, apparently from contaminants present in liver. This phenomenon was not observed using hepatic microsomes from laboratory-held catfish. Glucuronidation efficiency was much higher with 4'-OH-CB72 (Km 7.3 microM; Vmax 1.55 nmol/min/mg) than 4'-OH-CB159 (Km 16.1 microM; Vmax 0.46 nmol/min/mg). The identities of the aglycones present in polar bear liver are not known, but could include OH-PCBs or hydroxylated metabolites of other persistent organic pollutants. This study demonstrates that UGT with high activity for 3-OH-BaP and other substrates is present in polar bear liver.

  11. Did acetaminophen provoke the autism epidemic?

    PubMed

    Good, Peter

    2009-12-01

    Schultz et al (2008) raised the question whether regression into autism is triggered, not by the measles-mumps-rubella (MMR) vaccine, but by acetaminophen (Tylenol) given for its fever and pain. Considerable evidence supports this contention, most notably the exponential rise in the incidence of autism since 1980, when acetaminophen began to replace aspirin for infants and young children. The impetus for this shift - a Centers for Disease Control and Prevention warning that aspirin was associated with Reye's syndrome - has since been compellingly debunked. If aspirin is not to be feared as a cause of Reyes syndrome, and acetaminophen is to be feared as a cause of autism, can the autism epidemic be reversed by replacing acetaminophen with aspirin or other remedies?

  12. Acrolein, a highly toxic aldehyde generated under oxidative stress in vivo, aggravates the mouse liver damage after acetaminophen overdose.

    PubMed

    Arai, Tomoya; Koyama, Ryo; Yuasa, Makoto; Kitamura, Daisuke; Mizuta, Ryushin

    2014-01-01

    Although acetaminophen-induced liver injury in mice has been extensively studied as a model of human acute drug-induced hepatitis, the mechanism of liver injury remains unclear. Liver injury is believed to be initiated by metabolic conversion of acetaminophen to the highly reactive intermediate N-acetyl p-benzoquinoneimine, and is aggravated by subsequent oxidative stress via reactive oxygen species (ROS), including hydrogen peroxide (H2O2) and the hydroxyl radical (•OH). In this study, we found that a highly toxic unsaturated aldehyde acrolein, a byproduct of oxidative stress, has a major role in acetaminophen-induced liver injury. Acetaminophen administration in mice resulted in liver damage and increased acrolein-protein adduct formation. However, both of them were decreased by treatment with N-acetyl-L-cysteine (NAC) or sodium 2-mercaptoethanesulfonate (MESNA), two known acrolein scavengers. The specificity of NAC and MESNA was confirmed in cell culture, because acrolein toxicity, but not H2O2 or •OH toxicity, was inhibited by NAC and MESNA. These results suggest that acrolein may be more strongly correlated with acetaminophen-induced liver injury than ROS, and that acrolein produced by acetaminophen-induced oxidative stress can spread from dying cells at the primary injury site, causing damage to the adjacent cells and aggravating liver injury.

  13. IN VITRO GLUCURONIDATION OF APREPITANT: A MODERATE INHIBITOR OF UGT2B7

    PubMed Central

    House, Larry; Ramirez, Jacqueline; Seminerio, Michael; Mirkov, Snezana; Ratain, Mark J.

    2016-01-01

    Aprepitant, an oral antiemetic, commonly used in the prevention of chemotherapy-induced nausea and vomiting, is primarily metabolized by CYP3A4. Aprepitant glucuronidation has yet to be evaluated in humans. The contribution of human UDP-glucuronosyltransferase (UGT) isoforms to the metabolism of aprepitant was investigated by performing kinetic studies, inhibition studies, and correlation analyses. In addition, aprepitant was evaluated as an inhibitor of UGTs.Glucuronidation of aprepitant was catalyzed by UGT1A4 (82%), UGT1A3 (12%), and UGT1A8 (6%) and Kms were 161.6 ± 15.6 µM, 69.4 ± 1.9 µM, and 197.1 ± 28.2 µM, respectively. Aprepitant glucuronidation was significantly correlated with both UGT1A4 substrates anastrazole and imipramine (rs = 0.77, P < 0.0001 for both substrates; n = 44), and with the UGT1A3 substrate thyroxine (rs = 0.58, P < 0.0001; n = 44).We found aprepitant to be a moderate inhibitor of UGT2B7 with a Ki of ~10 µM for 4-MU, morphine, and zidovudine. Our results suggest aprepitant can alter clearance of drugs primarily eliminated by UGT2B7. Given the likelihood for first-pass metabolism by intestinal UGT2B7, this is of particular concern for oral aprepitant co-administered with oral substrates of UGT2B7, such as zidovudine and morphine. PMID:26053558

  14. Acetaminophen (paracetamol) oral absorption and clinical influences.

    PubMed

    Raffa, Robert B; Pergolizzi, Joseph V; Taylor, Robert; Decker, John F; Patrick, Jeffrey T

    2014-09-01

    Acetaminophen (paracetamol) is a widely used nonopioid, non-NSAID analgesic that is effective against a variety of pain types, but the consequences of overdose can be severe. Because acetaminophen is so widely available as a single agent and is increasingly being formulated in fixed-ratio combination analgesic products for the potential additive or synergistic analgesic effect and/or reduced adverse effects, accidental cumulative overdose is an emergent concern. This has rekindled interest in the sites, processes, and pharmacokinetics of acetaminophen oral absorption and the clinical factors that can influence these. The absorption of oral acetaminophen occurs primarily along the small intestine by passive diffusion. Therefore, the rate-limiting step is the rate of gastric emptying into the intestines. Several clinical factors can affect absorption per se or the rate of gastric emptying, such as diet, concomitant medication, surgery, pregnancy, and others. Although acetaminophen does not have the abuse potential of opioids or the gastrointestinal bleeding or organ adverse effects of NSAIDs, excess amounts can produce serious hepatic injury. Thus, an understanding of the sites and features of acetaminophen absorption--and how they might be influenced by factors encountered in clinical practice--is important for pain management using this agent. It can also provide insight for design of formulations that would be less susceptible to clinical variables.

  15. Limited Knowledge of Acetaminophen in Patients with Liver Disease

    PubMed Central

    Saab, Sammy; Konyn, Peter G.; Viramontes, Matthew R.; Jimenez, Melissa A.; Grotts, Jonathan F.; Hamidzadah, Wally; Dang, Veronica P.; Esmailzadeh, Negin L.; Choi, Gina; Durazo, Francisco A.; El-Kabany, Mohamed M.; Han, Steven-Huy B.; Tong, Myron J.

    2016-01-01

    Abstract Background and Aims: Unintentional acetaminophen overdose remains the leading cause of acute liver failure in the United States. Patients with underlying liver disease are at higher risk of poor outcomes from acetaminophen overdose. Limited knowledge of acetaminophen may be a preventable contributor to elevated rates of overdose and thus acute liver failure. The purpose of this study is to assess knowledge of acetaminophen dosing and presence of acetaminophen in common combination products in patients with liver disease. Methods: We performed a cross-sectional study of patients with liver disease at the Pfleger Liver Institute at the University of California, Los Angeles between June 2015 and August 2016. Patients completed a demographic questionnaire and an acetaminophen knowledge survey. Additional information was obtained from the medical record. Results: Of 401 patients with liver disease, 30 (15.7%) were able to correctly identify that people without liver disease can safely take up to 4 g/day of acetaminophen. The majority of patients (79.9%–86.8%) did not know that Norco® (hydrocone/acetaminophen), Vicodin® (hydrocone/acetaminophen) and Percocet® (oxycodone/acetaminophen) contained acetaminophen. Only 45.3% of the patients knew that Tylenol® #3 contained acetaminophen. Conclusions: We conclude that patients with liver disease have critically low levels of knowledge of acetaminophen, putting them at risk both of acetaminophen overdose, as well as undermedication, and inadequate management of chronic pain. We recommend an increase in education efforts regarding acetaminophen dosage and its safety in the setting of liver disease. Increasing education for those at risk of low acetaminophen knowledge is essential to minimizing acetaminophen overdose rates and optimizing pain management. PMID:28097095

  16. Involvement of UDP-glucuronosyltransferases UGT1A9 and UGT2B7 in ethanol glucuronidation, and interactions with common drugs of abuse.

    PubMed

    Al Saabi, Alaa; Allorge, Delphine; Sauvage, François-Ludovic; Tournel, Gilles; Gaulier, Jean-Michel; Marquet, Pierre; Picard, Nicolas

    2013-03-01

    Ethyl glucuronide (EtG) determination is increasingly used in clinical and forensic toxicology to document ethanol consumption. The enzymes involved in EtG production, as well as potential interactions with common drugs of abuse, have not been extensively studied. Activities of human liver (HLM), kidney (HKM), and intestinal (HIM) microsomes, as well as of 12 major human recombinant UDP-glucuronosyltransferases (UGTs), toward ethanol (50 and 500 mM) were evaluated in vitro using liquid chromatography-tandem mass spectrometry. Enzyme kinetic parameters were determined for pooled microsomes and recombinant UGTs with significant activity. Individual contributions of UGTs were estimated using the relative activity factor approach, proposed for scaling activities obtained with cDNA-expressed enzymes to HLM. Interaction of morphine, codeine, lorazepam, oxazepam, nicotine, cotinine, cannabinol, and cannabidiol (5, 10, 15 mg/l) with ethanol (1.15, 4.6, 11.5 g/l; i.e., 25, 100, 250 mM) glucuronidation was assessed using pooled HLM. Ethanol glucuronidation intrinsic clearance (Cl(int)) was 4 and 12.7 times higher for HLM than for HKM and HIM, respectively. All recombinant UGTs, except UGT1A1, 1A6, and 1A10, produced EtG in detectable amounts. UGT1A9 and 2B7 were the most active enzymes, each accounting for 17 and 33% of HLM Cl(int), respectively. Only cannabinol and cannabidiol significantly affected ethanol glucuronidation. Cannabinol increased ethanol glucuronidation in a concentration-dependent manner, whereas cannabidiol significantly inhibited EtG formation in a noncompetitive manner (IC(50) = 1.17 mg/l; inhibition constant (K(i)) = 3.1 mg/l). UGT1A9 and 2B7 are the main enzymes involved in ethanol glucuronidation. In addition, our results suggest that cannabinol and cannabidiol could significantly alter ethanol glucuronidation.

  17. Parents: Acetaminophen in Pain Relief Medicines Can Cause Liver Damage

    MedlinePlus

    ... Parents: Acetaminophen in pain relief medicines can cause liver damage Share Tweet Linkedin Pin it More sharing ... whole word or may have the abbreviation "APAP." Liver damage: Giving your child more acetaminophen than directed ...

  18. Analysis of R- and S-Hydroxywarfarin Glucuronidation Catalyzed by Human Liver Microsomes and Recombinant UDP-Glucuronosyltransferases

    PubMed Central

    Bratton, Stacie M.; Mosher, Carrie M.; Khallouki, Farid; Finel, Moshe; Court, Michael H.; Moran, Jeffery H.

    2012-01-01

    Coumadin (R-, S-warfarin) is a challenging drug to accurately dose, both initially and for maintenance, because of its narrow therapeutic range and wide interpatient variability and is typically administered as a racemic (Rac) mixture, which complicates the biotransformation pathways. The goal of the current work was to identify the human UDP-glucuronosyltransferases (UGTs) involved in the glucuronidation of the separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin and the possible interactions between these enantiomers. The kinetic and inhibition constants for human recombinant 1A family UGTs toward these separated enantiomers have been assessed using high-performance liquid chromatography (HPLC)-UV-visible analysis, and product confirmations have been made using HPLC-mass spectrometry/mass spectrometry. We found that separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin demonstrate significantly different glucuronidation kinetics and can be mutually inhibitory. In some cases significant substrate inhibition was observed, as shown by Km, Vmax, and Ki, comparisons. In particular, UGT1A1 and extrahepatic UGT1A10 have significantly higher capacities than other isoforms for S-7-hydroxywarfarin and R-7-hydroxywarfarin glucuronidation, respectively. Activity data generated using a set of well characterized human liver microsomes supported the recombinant enzyme data, suggesting an important (although not exclusive) role for UGT1A1 in glucuronidation of the main warfarin metabolites, including Rac-6- and 7-hydroxywarfarin and their R- and S-enantiomers in the liver. This is the first demonstration that the R- and S-enantiomers of hydroxywarfarins are glucuronidated, with significantly different enzymatic affinity and capacity, and supports the importance of UGT1A1 as the major hepatic isoform involved. PMID:21972237

  19. Structure- and isoform-specific glucuronidation of six curcumin analogs.

    PubMed

    Lu, Danyi; Liu, Hui; Ye, Wencai; Wang, Ying; Wu, Baojian

    2017-04-01

    1. In the present study, we aimed to characterize the glucuronidation of six curcumin analogs (i.e. RAO-3, RAO-8, RAO-9, RAO-18, RAO-19, and RAO-23) derived from galangal using human liver microsomes (HLM) and twelve expressed UGT enzymes. 2. Formation of glucuronide was confirmed using high-resolution mass spectrometry. Single glucuronide metabolite was generated from each of six curcumin analogs. The fragmentation patterns were analyzed and were found to differ significantly between alcoholic and phenolic glucuronides. 3. All six curcumin analogs except one (RAO-23) underwent significant glucuronidation in HLM and expressed UGT enzymes. In general, the methoxy group (close to the phenolic hydroxyl group) enhanced the glucuronidation liability of the curcumin analogs. 4. UGT1A9 and UGT2B7 were primarily responsible for the glucuronidation of two alcoholic analogs (RAO-3 and RAO-18). By contrast, UGT1A9 and four UGT2Bs (UGT2B4, 2B7, 2B15 and 2B17) played important roles in conjugating three phenolic analogs (RAO-8, RAO-9, and RAO-19). Interestingly, the conjugated double bonds system (in the aliphatic chain) was crucial to the substrate selectivity of gastrointestinal UGTs (i.e. UGT1A7, 1A8 and 1A10). 5. In conclusion, glucuronidation of six curcumin analogs from galangal were structure- and isoform-specific. The knowledge should be useful in identifying a curcumin analog with improved metabolic property.

  20. Transplacental Passage of Acetaminophen in Term Pregnancy.

    PubMed

    Nitsche, Joshua F; Patil, Avinash S; Langman, Loralie J; Penn, Hannah J; Derleth, Douglas; Watson, William J; Brost, Brian C

    2016-11-02

    Objective The objective of this study was to determine the maternal and fetal pharmacokinetic (PK) profiles of acetaminophen after administration of a therapeutic oral dose. Study Design After obtaining Institutional Review Board approval and their written informed consent, pregnant women were given a single oral dose (1,000 mg) of acetaminophen upon admission for scheduled cesarean delivery. Maternal venous blood and fetal cord blood were obtained at the time of delivery and acetaminophen levels were measured using gas chromatography-mass spectroscopy. PK parameters were calculated by noncompartmental analysis. Nonparametric correlation of maternal/fetal acetaminophen levels and PK curves were calculated. Results In this study, 34 subjects were enrolled (median, 32 years; range, 25-39 years). The median maternal weight was 82 kg (range, 62-100 kg). All but two subjects were delivered beyond 39 weeks' gestation. The median newborn birth weight was 3,590 g (interquartile range, 3,403-3,848 g). Noncompartmental analysis described similar PK parameters in the maternal (T1/2, 84 minutes; apparent clearance [Cl/F], 28.8 L/h; apparent volume of distribution [Vd/F], 57.5 L) and fetal compartments (T1/2, 82 minutes; Cl/F, 31.2 L/h; Vd/F, 61.2 L). Paired maternal/fetal acetaminophen levels were highly correlated (p < 0.0001). Conclusion Fetal acetaminophen PKs in the fetus parallels that in the mother suggesting that placental transfer is flow limited. Maternal acetaminophen levels can be used as a surrogate for fetal exposure.

  1. Glucuronidation of fenamates: kinetic studies using human kidney cortical microsomes and recombinant UDP-glucuronosyltransferase (UGT) 1A9 and 2B7.

    PubMed

    Gaganis, Paraskevi; Miners, John O; Knights, Kathleen M

    2007-05-15

    Mefenamic acid, a non-steroidal anti-inflammatory drug (NSAID), is used commonly to treat menorrhagia. This study investigated the glucuronidation kinetics of flufenamic, mefenamic and niflumic acid using human kidney cortical microsomes (HKCM) and recombinant UGT1A9 and UGT2B7. Using HKCM Michaelis-Menten (MM) kinetics were observed for mefenamic (K(m)(app) 23 microM) and niflumic acid (K(m)(app) 123 microM) glucuronidation, while flufenamic acid exhibited non-hyperbolic (atypical) glucuronidation kinetics. Notably, the intrinsic renal clearance of mefenamic acid (CL(int) 17+/-5.5 microL/minmg protein) was fifteen fold higher than that of niflumic acid (CL(int) 1.1+/-0.8 microL/minmg protein). These data suggest that renal glucuronidation of mefenamic acid may result in high intrarenal exposure to mefenamic acyl-glucuronide and subsequent binding to renal proteins. Diverse kinetics were observed for fenamate glucuronidation by UGT2B7 and UGT1A9. Using UGT2B7 MM kinetics were observed for flufenamic (K(m)(app) 48 microM) and niflumic acid (K(m)(app) 135 microM) glucuronidation and atypical kinetics with mefenamic acid. Similarity in K(m)(app) between HKCM and UGT2B7 suggests that UGT2B7 may be the predominant renal UGT isoform catalysing niflumic acid glucuronidation. In contrast, UGT1A9 glucuronidation kinetics were characterised by negative cooperativity with mefenamic (S(50) 449 microM, h 0.4) and niflumic acid (S(50) 7344 microM, h 0.4) while atypical kinetics were observed with flufenamic acid. Additionally, potent inhibition of the renal glucuronidation of the UGT substrate 'probe' 4-methylumbelliferone by flufenamic, mefenamic and niflumic acid was observed. These data suggest that inhibitory metabolic interactions may occur between fenamates and other substrates metabolised by UGT2B7 and UGT1A9 in human kidney.

  2. Serotonin deficiency exacerbates acetaminophen-induced liver toxicity in mice.

    PubMed

    Zhang, Jingyao; Song, Sidong; Pang, Qing; Zhang, Ruiyao; Zhou, Lei; Liu, Sushun; Meng, Fandi; Wu, Qifei; Liu, Chang

    2015-01-29

    Acetaminophen (APAP) overdose is a major cause of acute liver failure. Peripheral 5-hydroxytryptamine (serotonin, 5-HT) is a cytoprotective neurotransmitter which is also involved in the hepatic physiological and pathological process. This study seeks to investigate the mechanisms involved in APAP-induced hepatotoxicity, as well as the role of 5-HT in the liver's response to APAP toxicity. We induced APAP hepatotoxicity in mice either sufficient of serotonin (wild-type mice and TPH1-/- plus 5- Hydroxytryptophan (5-HTP)) or lacking peripheral serotonin (Tph1-/- and wild-type mice plus p-chlorophenylalanine (PCPA)). Mice with sufficient 5-HT exposed to acetaminophen have a significantly lower mortality rate and a better outcome compared with mice deficient of 5-HT. This difference is at least partially attributable to a decreased level of inflammation, oxidative stress and endoplasmic reticulum (ER) stress, Glutathione (GSH) depletion, peroxynitrite formation, hepatocyte apoptosis, elevated hepatocyte proliferation, activation of 5-HT2B receptor, less activated c-Jun NH₂-terminal kinase (JNK) and hypoxia-inducible factor (HIF)-1α in the mice sufficient of 5-HT versus mice deficient of 5-HT. We thus propose a physiological function of serotonin that serotonin could ameliorate APAP-induced liver injury mainly through inhibiting hepatocyte apoptosis ER stress and promoting liver regeneration.

  3. Bioavailability of the glucuronide and sulfate conjugates of genistein and daidzein in breast cancer resistance protein 1 knockout mice.

    PubMed

    Álvarez, Ana I; Vallejo, Fernando; Barrera, Borja; Merino, Gracia; Prieto, Julio G; Tomás-Barberán, Francisco; Espín, Juan C

    2011-11-01

    The dietary polyphenols genistein and daidzein are potent effectors of biological processes. The plasma profile of both isoflavones is governed by the presence of phase II conjugates, mainly glucuronides and sulfates. Breast cancer resistance protein (ABCG2/BCRP) interacts with genistein and daidzein, which are among the natural substrates of the transporter and competitively inhibit ABCG2-mediated drug efflux. ABCG2/BCRP can also transport glucuronide and sulfate conjugates. In this study, we analyzed the plasma levels of aglycones and derived conjugated metabolites, glucuronides, and sulfates, after intragastric administration of these isoflavones to wild-type and Bcrp1(-/-) knockout mice. The results show that overall plasmatic profile is mainly governed by sulfate and glucuronide derivatives, the concentration of which was significantly increased (7- to 10-fold) in Bcrp1(-/-) mice. The total AUC h nM (0-180 min), as the sum of aglycones, glucuronides, and sulfates, was 901 ± 207 in wild-type mice versus 4988 ± 508 in Bcrp1(-/-) mice after genistein administration (50 mg/kg b.wt.); 584.3 ± 90 in wild-type mice versus 4012 ± 612 in Bcrp1(-/-) after daidzein administration (50 mg/kg); and 926 ± 140 in wild-type mice versus 5174 ± 696 in Bcrp1(-/-) after genistein+daidzein administration (25 + 25 mg/kg). Therefore, our results indicate a direct and conclusive Bcrp1 efflux action on phase II metabolites of these isoflavones in vivo and suggest a possible novel concept for ABCG2/BCRP as part of metabolism-driven efflux transport of these conjugates.

  4. Kinetic modeling of the interactions between 4-methylumbelliferone, 1-naphthol, and zidovudine glucuronidation by udp-glucuronosyltransferase 2B7 (UGT2B7) provides evidence for multiple substrate binding and effector sites.

    PubMed

    Uchaipichat, Verawan; Galetin, Aleksandra; Houston, J Brian; Mackenzie, Peter I; Williams, J Andrew; Miners, John O

    2008-10-01

    Interactions between the UGT2B7-catalyzed glucuronidation of zidovudine (AZT), 4-methylumbelliferone (4MU), and 1-naphthol (1NP) were analyzed using multisite and empirical kinetic models to explore the existence of multiple substrate and effector binding sites within this important drug metabolizing enzyme. 4MU and 1NP glucuronidation by UGT2B7 exhibit sigmoidal kinetics characteristic of homotropic cooperativity (autoactivation), which may be modeled assuming the existence of two equivalent, interacting substrate binding sites. In contrast, UGT2B7-catalyzed AZT glucuronidation follows hyperbolic (Michaelis-Menten) kinetics. Although 4MU and 1NP decreased the binding affinity of AZT, the kinetics of AZT glucuronidation changed from hyperbolic to sigmoidal in the presence of both modifiers. Data were well described by a generic two-substrate binding site model in which there is no interaction between the sites in the absence of 4MU or 1NP, but heterotropic cooperativity results from the binding of modifier. Inhibition of 4MU and 1NP glucuronidation by AZT and interactions between 4MU and 1NP required more complex three-site models, where the modifier acts via a distinct effector site to alter either substrate binding affinity or Vmax without affecting the homotropic cooperativity characteristic of 4MU and 1NP glucuronidation. It is noteworthy that 1NP inhibited 4MU glucuronidation, whereas 4MU activated 1NP glucuronidation. The results are consistent with the existence of two "catalytic" sites for each substrate within the UGT2B7 active site, along with multiple effector sites. The multiplicity of binding and effector sites results in complex kinetic interactions between UGT2B7 substrates, which potentially complicates inhibition screening studies.

  5. [Acetaminophen (paracetamol) causing renal failure: report on 3 pediatric cases].

    PubMed

    Le Vaillant, J; Pellerin, L; Brouard, J; Eckart, P

    2013-06-01

    Renal failure secondary to acetaminophen poisoning is rare and occurs in approximately 1-2 % of patients with acetaminophen overdose. The pathophysiology is still being debated, and renal acetaminophen toxicity consists of acute tubular necrosis, without complication if treated promptly. Renal involvement can sometimes occur without prior liver disease, and early renal manifestations usually occur between the 2nd and 7th day after the acute acetaminophen poisoning. While therapy is exclusively symptomatic, sometimes serious metabolic complications can be observed. The monitoring of renal function should therefore be considered as an integral part of the management of children with acute, severe acetaminophen intoxication. We report 3 cases of adolescents who presented with acute renal failure as a result of voluntary drug intoxication with acetaminophen. One of these 3 girls developed severe renal injury without elevated hepatic transaminases. None of the 3 girls' renal function required hemodialysis, but one of the 3 patients had metabolic complications after her acetaminophen poisoning.

  6. Peristalsis in the Guinea pig small intestine in vitro is impaired by acetaminophen but not aspirin and dipyrone.

    PubMed

    Herbert, Michael K; Weis, Rebecca; Holzer, Peter; Roewer, Norbert

    2005-01-01

    Inhibition of intestinal peristalsis is a major side effect of opioid analgesics. It is unknown whether non-opioid analgesics, such as acetaminophen, acetylsalicylic acid, and dipyrone, exert any effect on intestinal motility. In the current in vitro study we examined the effect of these analgesics on intestinal peristalsis and analyzed some of their mechanisms of action. In isolated segments of the guinea pig small intestine peristalsis was triggered by a perfusion-induced increase of the intraluminal pressure. The peristaltic pressure threshold (PPT) at which peristaltic waves were elicited was used to quantify drug effects on peristalsis. Vehicle (Tyrode's solution), acetaminophen (0.01-100 microM), acetylsalicylic acid (100-300 microM), and dipyrone (10-100 microM) were added extraserosally to the organ bath. Acetaminophen concentration-dependently increased PPT and abolished peristalsis in four of six segments at the concentration of 10 microM and in all segments tested at 100 microM (EC50=6.0 microM). The increase in PPT resulting from 3 microM acetaminophen was reduced by naloxone and apamin but not changed by L-nitro-arginine methylester (L-NAME), its inactive enantiomer D-NAME, acetylsalicylic acid, methysergide, or tropisetron. Acetylsalicylic acid and dipyrone did not affect peristalsis. The results reveal, for the first time, that acetaminophen concentration-dependently impairs intestinal peristalsis, whereas acetylsalicylic acid and dipyrone lacked such an effect. The inhibition caused by acetaminophen involves transmitters acting via small conductance Ca2+-activated potassium channels, endogenous opioidergic pathways, and presumably inhibition of cyclooxygenase-3.

  7. Nonsteroidal antiinflammatory drugs, acetaminophen, and hypertension.

    PubMed

    Sudano, Isabella; Flammer, Andreas J; Roas, Susanne; Enseleit, Frank; Noll, Georg; Ruschitzka, Frank

    2012-08-01

    Selective and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) as well as acetaminophen belong to the most widely prescribed therapeutic agents worldwide. Their efficacy in pain relief notwithstanding, the use of NSAIDs is associated with an increased cardiovascular risk, which can be partly attributed to their blood pressure raising potential. Adequately powered placebo-controlled trials specifically evaluating the cardiovascular safety of NSAIDs vs. selective COX inhibitors are currently underway. This review summarizes the current knowledge on the cardiovascular effects of NSAIDs and acetaminophen, and their potential clinical consequences.

  8. Effect of sesame oil against acetaminophen-induced acute oxidative hepatic damage in rats.

    PubMed

    Chandrasekaran, Victor Raj Mohan; Wan, Chang-Hsin; Liu, Li-Lian; Hsu, Dur-Zong; Liu, Ming-Yie

    2008-08-01

    Acetaminophen (APAP) overdose causes acute liver injury or even death in both humans and experimental animals. We investigated the effect of sesame oil on APAP-induced acute liver injury. Male Wistar rats were given APAP (1,000 mg/kg; orally) to induce acute liver injury. Acetaminophen significantly increased aspartate transaminase, alanine transaminase, lipid peroxidation, and superoxide anion and hydroxyl radical generation levels; it also induced glutathione depletion. Sesame oil (8 mL/kg; orally) did not alter the gastric absorption of APAP, but it inhibited all the parameters altered by APAP and protected the rats against APAP-induced acute liver injury. We hypothesize that sesame oil maintained the intracellular glutathione levels, reduced reactive oxygen species levels, and inhibited lipid peroxidation in rats with APAP-induced acute liver injury.

  9. Glucuronidation of active tamoxifen metabolites by the human UDP glucuronosyltransferases.

    PubMed

    Sun, Dongxiao; Sharma, Arun K; Dellinger, Ryan W; Blevins-Primeau, Andrea S; Balliet, Renee M; Chen, Gang; Boyiri, Telih; Amin, Shantu; Lazarus, Philip

    2007-11-01

    Tamoxifen (TAM) is an antiestrogen that has been widely used in the treatment and prevention of breast cancer in women. One of the major mechanisms of metabolism and elimination of TAM and its major active metabolites 4-hydroxytamoxifen (4-OH-TAM) and 4-OH-N-desmethyl-TAM (endoxifen; 4-hydroxy-N-desmethyl-tamoxifen) is via glucuronidation. Although limited studies have been performed characterizing the glucuronidation of 4-OH-TAM, no studies have been performed on endoxifen. In the present study, characterization of the glucuronidating activities of human UDP glucuronosyltransferases (UGTs) against isomers of 4-OH-TAM and endoxifen was performed. Using homogenates of individual UGT-overexpressing cell lines, UGTs 2B7 approximately 1A8 > UGT1A10 exhibited the highest overall O-glucuronidating activity against trans-4-OH-TAM as determined by Vmax/K(M), with the hepatic enzyme UGT2B7 exhibiting the highest binding affinity and lowest K(M) (3.7 microM). As determined by Vmax/K(M), UGT1A10 exhibited the highest overall O-glucuronidating activity against cis-4-OH-TAM, 10-fold higher than the next-most active UGTs 1A1 and 2B7, but with UGT1A7 exhibiting the lowest K(M). Although both N- and O-glucuronidation occurred for 4-OH-TAM in human liver microsomes, only O-glucuronidating activity was observed for endoxifen; no endoxifen-N-glucuronidation was observed for any UGT tested. UGTs 1A10 approximately 1A8 > UGT2B7 exhibited the highest overall glucuronidating activities as determined by Vmax/K(M) for trans-endoxifen, with the extrahepatic enzyme UGT1A10 exhibiting the highest binding affinity and lowest K(M) (39.9 microM). Similar to that observed for cis-4-OH-TAM, UGT1A10 also exhibited the highest activity for cis-endoxifen. These data suggest that several UGTs, including UGTs 1A10, 2B7, and 1A8 play an important role in the metabolism of 4-OH-TAM and endoxifen.

  10. Morphine, morphine-6-glucuronide and morphine-3-glucuronide pharmacokinetics in newborn infants receiving diamorphine infusions.

    PubMed

    Barrett, D A; Barker, D P; Rutter, N; Pawula, M; Shaw, P N

    1996-06-01

    1. The pharmacokinetics of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) were studied in 19 ventilated newborn infants (24-41 weeks gestation) who were given a loading dose of 50 micrograms kg-1 or 200 micrograms kg-1 of diamorphine followed by an intravenous infusion of 15 micrograms kg-1 h-1 of diamorphine. Plasma concentrations of morphine, M3G and M6G were measured during the accrual to steady-state and at steady state of the diamorphine infusion. 2. Following both the 50 micrograms kg-1 or 200 micrograms kg-1 loading doses the mean steady-state plasma concentration (+/- s.d.) of morphine, M3G and M6G were 86 +/- 52 ng ml-1, 703 +/- 400 ng ml-1 and 48 +/- 28 ng ml-1 respectively and morphine clearance was found to be 4.6 +/- 3.2 ml min-1 kg-1. 3. M3G formation clearance was estimated to be 2.5 +/- 1.8 ml min-1 kg-1, and the formation clearance of M6G was estimated to be 0.46 +/- 0.32 ml min-1 kg-1. 4. M3G metabolite clearance was 0.46 +/- 0.60 ml min-1 kg-1, the elimination half-life was 11.1 +/- 11.3 h and the volume of distribution was 0.55 +/- 1.13 l kg-1. M6G metabolite clearance was 0.71 +/- 0.36 ml min-1 kg-1, the elimination half-life was 18.2 +/- 13.6 h and the volume of distribution was 1.03 +/- 0.88 l kg-1. 5. No significant effect of the loading dose (50 micrograms kg-1 or 200 micrograms kg-1) on the plasma morphine or metabolite concentrations or their derived pharmacokinetic parameters was found. 6. We were unable to identify correlations between gestational age of the infants and any of the determined pharmacokinetic parameters. 7. M3G: morphine and M6G: morphine steady-state plasma concentration ratios were 11.0 +/- 10.8 and 0.8 +/- 0.8, respectively. 8. The metabolism of morphine in neonates, in terms of the respective contributions of each glucuronide pathway, was similar to that in adults.

  11. Microvascular protective activity of flavonoid glucuronides fraction from Tulipa gesneriana.

    PubMed

    Budzianowski, J; Korzeniowska, K; Chmara, E; Mrozikiewicz, A

    1999-03-01

    A mixture of flavonoid glucuronides, consisting of 7-O-glucuronides of kaempferol and quercetin 3-O-rutinosides, 3-O-gentiobiosides and 3-O-glucosides, was isolated from the perianths of Tulipa gesneriana L. var. 'Paradae'. It showed protective activity against the increased (both chloroform and histamine) skin vascular permeability in rabbits. The protective effect, measured as the reduction in leakage of Evans blue, was 59.8% after peritoneal treatment at a dose of 25 mg/kg, while that of troxerutin was 45.5%.

  12. Inhibitory effect of ciprofloxacin on β-glucuronidase-mediated deconjugation of mycophenolic acid glucuronide.

    PubMed

    Kodawara, Takaaki; Masuda, Satohiro; Yano, Yoshitaka; Matsubara, Kazuo; Nakamura, Toshiaki; Masada, Mikio

    2014-07-01

    The interaction between mycophenolate (MPA) and quinolone antibiotics such as ciprofloxacin is considered to reduce the enterohepatic recycling of MPA, which is biotransformed in the intestine from MPA glucuronide (MPAG) conjugate excreted via the biliary system; however, the molecular mechanism underlying this biotransformation of MPA is still unclear. In this study, an in vitro system was established to evaluate β-glucuronidase-mediated deconjugation and to examine the influence of ciprofloxacin on the enzymatic deconjugation of MPAG and MPA resynthesis. Resynthesis of MPA via deconjugation of MPAG increased in a time-dependent manner from 5 to 60 min in the presence of β-glucuronidase. Ciprofloxacin and phenolphthalein-β-d-glucuronide (PhePG), a typical β-glucuronidase substrate, significantly decreased the production of MPA from MPAG in the β-glucuronidase-mediated deconjugation system. In addition, enoxacin significantly inhibited the production of MPA from MPAG, while levofloxacin and ofloxacin had no inhibitory effect on MPA synthesis. Pharmacokinetic analysis revealed that ciprofloxacin showed a dose-dependent inhibitory effect on MPA production from MPAG via β-glucuronidase with a half-maximal inhibitory concentration (IC50 ) value of 30.4 µm. While PhePG inhibited the β-glucuronidase-mediated production of MPA from MPAG in a competitive manner, ciprofloxacin inhibited MPA synthesis via noncompetitive inhibition. These findings suggest that the reduction in the serum MPA concentration during the co-administration of ciprofloxacin is at least in part due to the decreased enterohepatic circulation of MPA because of noncompetitive inhibition of deconjugation of MPAG by intestinal β-glucuronidase.

  13. Quantitation of Buprenorphine, Norbuprenorphine, Buprenorphine Glucuronide, Norbuprenorphine Glucuronide, and Naloxone in Urine by LC-MS/MS.

    PubMed

    Marin, Stephanie J; McMillin, Gwendolyn A

    2016-01-01

    Buprenorphine is an opioid drug that has been used to treat opioid dependence on an outpatient basis, and is also prescribed for managing moderate to severe pain. Some formulations of buprenorphine also contain naloxone to discourage misuse. The major metabolite of buprenorphine is norbuprenorphine. Both compounds are pharmacologically active and both are extensively metabolized to their glucuronide conjugates, which are also active metabolites. Direct quantitation of the glucuronide conjugates in conjunction with free buprenorphine, norbuprenorphine, and naloxone in urine can distinguish compliance with prescribed therapy from specimen adulteration intended to mimic compliance with prescribed buprenorphine. This chapter quantitates buprenorphine, norbuprenorphine, their glucuronide conjugates and naloxone directly in urine by liquid chromatography tandem mass spectrometry (LC-MS/MS). Urine is pretreated with formic acid and undergoes solid phase extraction (SPE) prior to analysis by LC-MS/MS.

  14. Acetaminophen Attenuates Lipid Peroxidation in Children Undergoing Cardiopulmonary Bypass

    PubMed Central

    Simpson, Scott A.; Zaccagni, Hayden; Bichell, David P.; Christian, Karla G.; Mettler, Bret A.; Donahue, Brian S.; Roberts, L. Jackson; Pretorius, Mias

    2014-01-01

    Objective Hemolysis, occurring during cardiopulmonary bypass (CPB), is associated with lipid peroxidation and postoperative acute kidney injury (AKI). Acetaminophen (ApAP) inhibits lipid peroxidation catalyzed by hemeproteins and in an animal model attenuated rhabdomyolysis-induced AKI. This pilot study tests the hypothesis that ApAP attenuates lipid peroxidation in children undergoing CPB. Design Single center prospective randomized double blinded study. Setting University-affiliated pediatric hospital. Patients Thirty children undergoing elective surgical correction of a congenital heart defect. Interventions Patients were randomized to ApAP (OFIRMEV® (acetaminophen) injection, Cadence Pharmaceuticals, San Diego, CA) or placebo every 6 hours for 4 doses starting before the onset of CPB. Measurement and Main Results Markers of hemolysis, lipid peroxidation (isofurans and F2-isoprostanes) and AKI were measured throughout the perioperative period. CPB was associated with a significant increase in free hemoglobin (from a pre-bypass level of 9.8±6.2 mg/dl to a peak of 201.5±42.6 mg/dl post-bypass). Plasma and urine isofuran and F2-isoprostane concentrations increased significantly during surgery. The magnitude of increase in plasma isofurans was greater than the magnitude in increase in plasma F2-isoprostanes. ApAP attenuated the increase in plasma isofurans compared to placebo (P=0.02 for effect of study drug). There was no significant effect of ApAP on plasma F2-isoprostanes or urinary makers of lipid peroxidation. ApAP did not affect postoperative creatinine, urinary neutrophil gelatinase-associated lipocalin or prevalence of AKI. Conclusion CPB in children is associated with hemolysis and lipid peroxidation. ApAP attenuated the increase in plasma isofuran concentrations. Future studies are needed to establish whether other therapies that attenuate or prevent the effects of free hemoglobin result in more effective inhibition of lipid peroxidation in patients

  15. Cremophor EL-based nanoemulsion enhances transcellular permeation of emodin through glucuronidation reduction in UGT1A1-overexpressing MDCKII cells.

    PubMed

    Zhang, Tianpeng; Dong, Dong; Lu, Danyi; Wang, Shuai; Wu, Baojian

    2016-03-30

    Oral emodin, a natural anthraquinone and active component of many herbal medicines, is poorly bioavailable because of extensive first-pass glucuronidation. Here we aimed to prepare emodin nanoemulsion (EMO-NE) containing cremophor EL, and to assess its potential for enhancing transcellular absorption of emodin using UGT1A1-overexpressing MDCKII cells (or MDCK1A1 cells). EMO-NE was prepared using a modified emulsification technique and subsequently characterized by particle size, morphology, stability, and drug release. MDCKII cells were stably transfected with UGT1A1 using the lentiviral transfection approach. Emodin transport and metabolism were evaluated in Transwell-cultured MDCK1A1 cells after apical dosing of EMO-NE or control solution. The obtained EMO-NE (116 ± 6.5 nm) was spherical and stable for at least 2 months. Emodin release in vitro was a passive diffusion-driven process. EMO-NE administration increased the apparent permeability of emodin by a 2.3-fold (p<0.001) compared to the pure emodin solution (1.2 × 10(-5) cm/s vs 5.3 × 10(-6) cm/s). Further, both apical and basolateral excretion of emodin glucuronide (EMO-G) were significantly decreased (≥56.5%, p<0.001) in EMO-NE group. This was accompanied by a marked reduction (57.4%, p<0.001) in total emodin glucuronidation. It was found that the reduced glucuronidation was due to inhibition of cellular metabolism by cremophor EL. Cremophor EL inhibited UGT1A1-mediated glucuronidation of emodin using the mixed-type inhibition mechanism. In conclusion, cremophor EL-based nanoemulsion greatly enhanced transcellular permeation of emodin through inhibition of UGT metabolism. This cremophor EL-based nanoformulation may be a promising strategy to improve the oral bioavailability of emodin.

  16. Acetaminophen-induced cellulitis-like fixed drug eruption.

    PubMed

    Fathallah, Neila; Ben Salem, Chaker; Slim, Raoudha; Boussofara, Lobna; Ghariani, Najet; Bouraoui, Kamel

    2011-03-01

    Acetaminophen is a widely used analgesic drug. Its adverse reactions are rare but severe. An 89-year-old man developed an indurated edematous and erythematous plaque on his left arm 1 day after acetaminophen ingestion. Cellulitis was suspected and antibiotictherapy was started but there was no improvement of the rash; there was a spectacular extension of the lesion with occurrence of flaccid vesicles and blisters in the affected sites. The diagnosis of generalized-bullous-fixed drug eruption induced by acetaminophen was considered especially with a reported history of a previous milder reaction occurring in the same site. Acetaminophen was withdrawn and the rash improved significantly. According to the Naranjo probability scale, the eruption experienced by the patient was probably due to acetaminophen. Clinicians should be aware of the ability of acetaminophen to induce fixed drug eruption that may clinically take several aspects and may be misdiagnosed.

  17. A Randomized Controlled Trial on Analgesic Effects of Intravenous Acetaminophen versus Dexamethasone after Pediatric Tonsillectomy

    PubMed Central

    Faiz, Seyed Hamid Reza; Rahimzadeh, Poupak; Alebouyeh, Mahmoud Reza; Sedaghat, Minow

    2013-01-01

    Background A few studies are available actually comparing the clinical efficacy of intravenous acetaminophen with other medications such as dexamethasone to inhibit postoperative adverse events in children. Objectives This randomized blinded controlled trial was designed to compare controlling status of postoperative events in children after tonsillectomy randomized to receive either intravenous acetaminophen or dexamethasone. Patients and Methods Eighty four children aged between 4 to 13 undergoing tonsillectomy were randomized using a computer-generated schedule to double-blind treatment with intravenous acetaminophen (15 mg/kg) or intravenous dexamethasone (0.1 mg/kg). Children were post-operatively assessed for swallowing pain, pain while opening mouth, ear pain, and postoperative sore throat in recovery room (within one hour after surgery), at the time of admission to the ward, as well as at 12 and 24 hours after surgery, assessed by the objective pain scoring system (OPS; minimum score: 0 = no pain, maximum score: 10 = extreme pain). Results There were no significant differences between the two groups with regard to the severity of postoperative pain due to swallowing or opening mouth measured at the different study time points from postoperative recovery to 24 hours after the surgery. There was no difference in ear pain severity at the time of postoperative recovery, at the admission time to ward and also at 12 hours after surgery; however mean score of ear pain severity was significantly higher in those who administered acetaminophen 24 hours after operation. Also, the mean score severity of sore throat was significantly higher in the acetaminophen compared with the dexamethasone group within 12 hours of surgery. Postoperative vomiting and bleeding were similarly observed between the two study groups. The severity of swallowing pain, pain while opening mouth, ear pain, as well as postoperative sore throat as gradually assuaged within 24 hours of

  18. Magnetic beads as an extraction medium for simultaneous quantification of acetaminophen and structurally related compounds in human serum.

    PubMed

    Bylda, Caroline; Velichkova, Vanya; Bolle, Jens; Thiele, Roland; Kobold, Uwe; Volmer, Dietrich A

    2015-06-01

    This paper describes a sample preparation method that complements a previously published liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for acetaminophen and eight structurally-related compounds in human serum (C. Bylda, R. Thiele, U. Kobold, D.A. Volmer. Drug Test. Anal. 2014, 6, 451). The analytes (acetaminophen [APAP] + metabolites acetaminophen-glucuronide [APG], -cysteine [APC], -mercapturate [APM] and -cysteine [APC], structurally similar analogues phenacetin and p-phenetidine, as well as tricyclic antidepressants imipramine and amitryptiline) were extracted from serum using magnetized hyper-crosslinked polystyrene particles. The sample preparation protocol was developed by means of a design of experiments (DoE) statistical approach. Using three representative compounds from the analyte panel with different polarities (high, medium, and low), two screening designs were used to identify factors that exhibited significant impact on recovery of the analytes. These parameters were then optimized to permit extraction of the complete target panel exhibiting a broad range of chemical polarities. Liquid chromatographic separations were achieved by gradient elution using a pentafluorphenyl column with subsequent detection by electrospray ionization-triple quadrupole mass spectrometry in multiple reaction monitoring (MRM) mode. The method was linear over the range 0.1-100 µg/mL for APAP, APG, p-phenetidine and phenacetin, 0.03-50 µg/mL for APS, and 0.01-10 µg/mL for APM, APC, imipramine and amitriptyline, with R(2)  > 0.99. The assay exhibited good precision with CVs ranging from 2 to 9% for all analytes; the accuracy was assessed by comparing two LC-MS/MS methods using a set of 68 patient samples.

  19. In Vitro Glucuronidation of Fenofibric Acid by Human UDP-Glucuronosyltransferases and Liver Microsomes

    PubMed Central

    Tojcic, Jelena; Benoit-Biancamano, Marie-Odile; Court, Michael H.; Straka, Robert J.; Caron, Patrick

    2009-01-01

    Fenofibric acid (FA), the active moiety of fenofibrate, is an agonist of the peroxisome proliferator-activated nuclear receptor α that modulates triglyceride and cholesterol profiles. Lipid response to fenofibrate and FA serum concentrations is highly variable. Although FA is reported to be almost exclusively inactivated by UDP-glucuronosyltransferases (UGTs) into FA-glucuronide (FA-G), the contribution of UGT isoenzymes has never been systematically assessed. Heterologously expressed human UGT1A and UGT2B and their coding variants were tested for FA glucuronidation using liquid chromatography/mass spectrometry. Recombinant UGT2B7 presented the highest Vmax/Km value (2.10 μl/min/mg), 16-fold higher than the activity of other reactive UGTs, namely, UGT1A3, UGT1A6, and UGT1A9 (0.13, 0.09, and 0.02 μl/min/mg, respectively). UGT2B7.1 (His268) and UGT2B7.2 (Tyr268) enzyme activity was similar, whereas UGT1A3.2 (R11A47), UGT1A3.3 (Trp11), and UGT1A9.3 (Thr33) showed 61 to 96% reduced Vmax/Km values compared with the respective (1) reference proteins. FA-G formation by a human liver bank (n = 48) varied by 10-fold, but the rate of formation was not associated with common genetic variations in UGT1A3, UGT1A6, UGT1A9, and UGT2B7. Correlation with activities for the probe substrates zidovudine (UGT2B7; r2 = 0.75), mycophenolic acid (UGT1A9; r2 = 0.42), fulvestrant (UGT1A3; r2 = 0.36), but not serotonin (UGT1A6; r2 = 0.06) indicated a primary role for UGT2B7 and lesser roles of UGT1A9 and UGT1A3 in hepatic FA glucuronidation. This was confirmed by a strong correlation of FA-G formation with UGT2B7 protein content and inhibition by fluconazole, a known UGT2B7 selective inhibitor. Additional studies are required to identify genetic factors contributing to the observed FA glucuronidation variability. PMID:19661212

  20. Stereoselective pharmacokinetics of ketoprofen and ketoprofen glucuronide in end-stage renal disease: evidence for a ‘futile cycle’ of elimination

    PubMed Central

    Grubb, N G; Rudy, D W; Brater, D C; Hall, S D

    1999-01-01

    Aims To assess if futile cycling of ketoprofen occurs in patients with decreased renal function. Methods Ketoprofen was administered to six haemodialysis-dependent patients with end-stage renal disease as single (50 mg) or multiple doses (50 mg three times daily, for 7 days). Plasma and dialysate concentrations of the unconjugated and glucuronidated R- and S-enantiomers of ketoprofen were determined using h.p.l.c. following the single and multiple dosing. Results The oral clearance was decreased and terminal elimination half-lives of R- and S-ketoprofen and the corresponding acyl glucuronides were increased in functionally anephric patients compared with healthy subjects. In contrast with the R-isomers, S-ketoprofen and S-ketoprofen glucuronide exhibited an unexpected accumulation (2.7–3.8 fold) after repeated dosing achieving S:R ratios of 3.3±1.7 and 11.2±5.3, respectively. The plasma dialysis clearances for R- and S-ketoprofen glucuronides were 49.4±19.8 and 39.0±15.9 ml min−1, respectively, and 10.8±17.6 and 13.3±23.5 ml min−1 for unconjugated R- and S-ketoprofen. Conclusions The selective accumulation of S-ketoprofen and its acyl glucuronide are consistent with amplification of chiral inversion subsequent to futile cycling between R-ketoprofen and R-ketoprofen glucuronide. Severe renal insufficiency, and possibly more modest decrements, results in a disproportionate increase in systemic exposure to the S-enantiomer which inhibits both pathologic and homeostatic prostaglandin synthesis. PMID:10583018

  1. Fate of glucuronide conjugated estradiol in the environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate and transport of conjugated reproductive hormones, which are polar compared to parent hormones, are little understood. Laboratory bench-scale soil (Hamar; Sandy, mixed, frigid typic Endoaquolls) sorption studies were conducted using [14C] 17ß-estradiol-3-glucuronide for a range of concentra...

  2. Decreased Expression of Multidrug Resistance-Associated Protein 4 (MRP4/ABCC4) Leads to Reduced Glucuronidation of Flavonoids in UGT1A1-Overexpressing HeLa Cells: The Role of Futile Recycling.

    PubMed

    Sun, Hua; Zhou, Xiaotong; Zhang, Xingwang; Wu, Baojian

    2015-07-08

    In this study, the role of futile recycling (or deglucuronidation) in the disposition of two flavonoids (i.e., genistein and apigenin) was explored using UGT1A1-overexpressing HeLa cells (or HeLa1A1 cells). Glucuronidation of the flavonoids by HeLa1A1 cell lysate followed the substrate inhibition kinetics (Vmax = 0.10 nmol/min/mg, Km = 0.54 μM, and Ksi = 2.0 μM for genistein; Vmax = 0.19 nmol/min/mg, Km = 0.56 μM, and Ksi = 3.7 μM for apigenin). Glucuronide was efficiently generated and excreted after incubation of the cells with the aglycone (at doses of 1.25-20 nmol). The excretion rates were 0.40-0.69 and 0.84-1.1 nmol/min/mg protein for genistein glucuronide (GG) and apigenin glucuronide (AG), respectively. Furthermore, glucuronide excretion and total glucuronidation were significantly reduced in MRP4 knocked-down as compared to control cells. The alterations were well characterized by a two-compartment pharmacokinetic model incorporating the process of futile recycling (defined by a first-order rate constant, Kde). The derived Kde values were 15 and 25 h(-1) for GG and AG, respectively. This was well consistent with the in vitro observation that AG was subjected to more efficient futile recycling compared to GG. In conclusion, futile recycling was involved in cellular glucuronidation, accounting for transporter-dependent glucuronidation of flavonoids.

  3. Enantiomer selective glucuronidation of the non-steroidal pure anti-androgen bicalutamide by human liver and kidney: role of the human UDP-glucuronosyltransferase (UGT)1A9 enzyme.

    PubMed

    Grosse, Laurent; Campeau, Anne-Sophie; Caron, Sarah; Morin, Frédéric-Alexandre; Meunier, Kim; Trottier, Jocelyn; Caron, Patrick; Verreault, Mélanie; Barbier, Olivier

    2013-08-01

    Bicalutamide (Casodex(®) ) is a non-steroidal pure anti-androgen used in the treatment of localized prostate cancer. It is a racemate drug, and its activity resides in the (R)-enantiomer, with little in the (S)-enantiomer. A major metabolic pathway for bicalutamide is glucuronidation catalysed by UDP-glucuronosyltransferase (UGT) enzymes. While (S)bicalutamide is directly glucuronidated, (R)bicalutamide requires hydroxylation prior to glucuronidation. The contribution of human tissues and UGT isoforms in the metabolism of these enantiomers has not been extensively investigated. In this study, both (R) and/or (S)bicalutamide were converted into glucuronide (-G) derivatives after incubation of pure and racemic solutions with microsomal extracts from human liver and kidney. Intestinal microsomes exhibited only low reactivity with these substrates. Km values of liver and kidney samples for (S)bicalutamide glucuronidation were similar, and lower than values obtained with the (R)-enantiomer. Among the 16 human UGTs tested, UGT1A8 and UGT1A9 were able to form both (S) and (R)bicalutamide-G from pure or racemic substrates. UGT2B7 was also able to form (R)bicalutamide-G. Kinetic parameters of the recombinant UGT2B7, UGT1A8 and UGT1A9 enzymes support a predominant role of the UGT1A9 isoform in bicalutamide metabolism. Accordingly, (S)bicalutamide inhibited the ability of human liver and kidney microsomes to glucuronidate the UGT1A9 probe substrate, propofol. In conclusion, the present study provides the first comprehensive analysis of in vitro bicalutamide glucuronidation by human tissues and UGTs and identifies UGT1A9 as a major contributor for (R) and (S) glucuronidation in the human liver and kidney.

  4. Enantiomer selective glucuronidation of the non-steroidal pure anti-androgen bicalutamide by human liver and kidney: role of the human UDP-glucuronosyltransferase (UGT)1A9 enzyme

    PubMed Central

    Grosse, Laurent; Campeau, Anne-Sophie; Caron, Sarah; Morin, Frédéric-Alexandre; Meunier, Kim; Trottier, Jocelyn; Caron, Patrick; Verreault, Mélanie; Barbier, Olivier

    2013-01-01

    Bicalutamide (Casodex®) is a non-steroidal pure anti-androgen used in the treatment of localized prostate cancer. It is a racemate drug and its activity resides in the (R)-enantiomer, with little in the (S)-enantiomer. A major metabolic pathway for bicalutamide is glucuronidation catalyzed by UDP-glucuronosyltransferase (UGT) enzymes. While (S)bicalutamide is directly glucuronidated, (R)bicalutamide requires hydroxylation prior to glucuronidation. The contribution of human tissues and UGT isoforms in the metabolism of these enantiomers has not been extensively investigated. In this study, both (R) and/or (S)bicalutamide were converted into glucuronide (-G) derivatives following incubation of pure and racemic solutions with microsomal extracts from human liver and kidney. Intestinal microsomes exhibited only low reactivity with these substrates. Km values of liver and kidney samples for (S)bicalutamide glucuronidation were similar, and lower than values obtained with the (R)-enantiomer. Among the 16 human UGTs tested, UGT1A8 and UGT1A9 were able to form both (S) and (R)bicalutamide-G from pure or racemic substrates. UGT2B7 was also able to form (R)bicalutamide-G. Kinetic parameters of the recombinant UGT2B7, UGT1A8 and UGT1A9 enzymes support a predominant role of the UGT1A9 isoform in bicalutamide metabolism. Accordingly, (S)bicalutamide inhibited the ability of human liver and kidney microsomes to glucuronidate the UGT1A9 probe substrate, propofol. In conclusion, the present study provides the first comprehensive analysis of in vitro bicalutamide glucuronidation by human tissues and UGTs, and identifies UGT1A9 as a major contributor for (R) and (S) glucuronidation in the human liver and kidney. PMID:23527766

  5. Acetaminophen overdose associated with double serum concentration peaks

    PubMed Central

    Papazoglu, Cristian; Ang, Jonathan R.; Mandel, Michael; Basak, Prasanta; Jesmajian, Stephen

    2015-01-01

    Acetaminophen is the most commonly used analgesic–antipyretic medication in the United States. Acetaminophen overdose, a frequent cause of drug toxicity, has been recognized as the leading cause of fatal and non-fatal hepatic necrosis. N-Acetylcysteine is the recommended antidote for acetaminophen poisoning. Despite evidence on the efficacy of N-acetylcysteine for prevention of hepatic injury, controversy persists about the optimal duration of the therapy. Here, we describe the case of a 65-year-old male with acetaminophen overdose and opioid co-ingestion who developed a second peak in acetaminophen serum levels after completing the recommended 21-hour intravenous N-acetylcysteine protocol and when the standard criteria for monitoring drug levels was achieved. Prolongation of N-acetylcysteine infusion beyond the standard protocol, despite a significant gap in treatment, was critical for successful avoidance of hepatotoxicity. Delay in acetaminophen absorption may be associated with a second peak in serum concentration following an initial declining trend, especially in cases of concomitant ingestion of opioids. In patients with acetaminophen toxicity who co-ingest other medications that may potentially delay gastric emptying or in those with risk factors for delayed absorption of acetaminophen, we recommend close monitoring of aminotransferase enzyme levels, as well as trending acetaminophen concentrations until undetectable before discontinuing the antidote therapy. PMID:26653695

  6. Morphine, morphine-6-glucuronide and morphine-3-glucuronide pharmacokinetics in newborn infants receiving diamorphine infusions

    PubMed Central

    BARRETT, D. A.; BARKER, D. P.; RUTTER, N.; PAWULA, M.; SHAW, P. N.

    1996-01-01

    1The pharmacokinetics of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) were studied in 19 ventilated newborn infants(24–41 weeks gestation) who were given a loading dose of 50 μg kg−1 or 200 μg kg−1 of diamorphine followed by an intravenous infusion of 15 μg kg−1 h−1 of diamorphine. Plasma concentrations of morphine, M3G and M6G were measured during the accrual to steady-state and at steady state of the diamorphine infusion. 2Following both the 50 μg kg−1 or 200 μg kg−1 loading doses the mean steady-state plasma concentration (±s.d.) of morphine, M3G and M6G were 86±52 ng ml−1, 703±400 ng ml−1 and 48±28 ng ml−1 respectively and morphine clearance was found to be 4.6±3.2 ml min−1 kg−1. 3M3G formation clearance was estimated to be 2.5±1.8 ml min−1 kg−1, and the formation clearance of M6G was estimated to be 0.46±0.32 ml min−1 kg−1. 4M3G metabolite clearance was 0.46±0.60 ml min−1 kg−1, the elimination half-life was 11.1±11.3 h and the volume of distribution was 0.55±1.13 l kg−1. M6G metabolite clearance was 0.71±0.36 ml min−1 kg−1, the elimination half-life was 18.2±13.6 h and the volume of distribution was 1.03±0.88 l kg−1. 5No significant effect of the loading dose (50 μg kg−1 or 200 μg kg−1) on the plasma morphine or metabolite concentrations or their derived pharmacokinetic parameters was found. 6We were unable to identify correlations between gestational age of the infants and any of the determined pharmacokinetic parameters. 7M3G:morphine and M6G:morphine steady-state plasma concentration ratios were 11.0±10.8 and 0.8±0.8, respectively. 8The metabolism of morphine in neonates, in terms of the respective contributions of each glucuronide pathway, was similar to that in adults. PMID:8799518

  7. Immunochemical quantitation of 3-(cystein-S-yl)acetaminophen adducts in serum and liver proteins of acetaminophen-treated mice.

    PubMed

    Pumford, N R; Hinson, J A; Potter, D W; Rowland, K L; Benson, R W; Roberts, D W

    1989-01-01

    Using a recently developed enzyme-linked immunosorbent assay specific for 3-(cystein-S-yl)acetaminophen adducts we have quantitated the formation of these specific adducts in liver and serum protein of B6C3F1 male mice dosed with acetaminophen. Administration of acetaminophen at doses of 50, 100, 200, 300, 400 and 500 mg/kg to mice resulted in evidence of hepatotoxicity (increase in serum levels of alanine aminotransferase and aspartate aminotransferase) at 4 hr in the 300, 400 and 500 mg/kg treatment groups only. The formation of 3-(cystein-S-yl)acetaminophen adducts in liver protein was not observed in the groups receiving 50, 100 and 200 mg/kg doses, but was observed in the groups receiving doses above 300 mg/kg of acetaminophen. Greater levels of adduct formation were observed at the higher doses. 3-(Cystein-S-yl)acetaminophen protein adducts were also observed in serum of mice receiving hepatotoxic doses of acetaminophen. After a 400 mg/kg dose of acetaminophen, 3-(cystein-S-yl)acetaminophen adducts in the liver protein reached peak levels 2 hr after dosing. By 12 hr the levels decreased to approximately 10% of the peak level. In contrast, 3-(cystein-S-yl)acetaminophen adducts in serum protein were delayed, reaching a sustained peak 6 to 12 hr after dosing. The dose-response correlation between the appearance of serum aminotransferases and 3-(cystein-S-yl)acetaminophen adducts in serum protein and the temporal correlation between the decrease in 3-(cystein-S-yl)acetaminophen adducts in liver protein and the appearance of adducts in serum protein are consistent with a hepatic origin of the adducts detected in serum protein.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Interindividual variability in nicotine metabolism: C-oxidation and glucuronidation.

    PubMed

    Nakajima, Miki; Yokoi, Tsuyoshi

    2005-08-01

    Nicotine has roles in the addiction to smoking, replacement therapy for smoking cessation, as a potential medication for several diseases such as Parkinson's disease, Alzheimer's disease, and ulcerative colitis. The absorbed nicotine is rapidly and extensively metabolized and eliminated to urine. A major pathway of nicotine metabolism is C-oxidation to cotinine, which is catalyzed by CYP2A6 in human livers. Cotinine is subsequently metabolized to trans-3'-hydroxycotinine by CYP2A6. Nicotine and cotinine are glucuronidated to N-glucuronides mainly by UGT1A4 and partly by UGT1A9. Trans-3'-hydroxycotinine is glucuronidated to O-glucuronide mainly by UGT2B7 and partly by UGT1A9. Approximately 90% of the total nicotine uptake is eliminated as these metabolites and nicotine itself. The nicotine metabolism is an important determinant of the clearance of nicotine. Recently, advances in the understanding of the interindividual variability in nicotine metabolism have been made. There are substantial data suggesting that the large interindividual differences in cotinine formation are associated with genetic polymorphisms of the CYP2A6 gene. Interethnic differences have also been observed in the cotinine formation and the allele frequencies of the CYP2A6 alleles. Since the genetic polymorphisms of the CYP2A6 gene have a major impact on nicotine clearance, its relationships with smoking behavior or the risk of lung cancer have been suggested. The metabolic pathways of the glucuronidation of nicotine, cotinine, and trans-3'-hydroxycotinine in humans would be one of the causal factors for the interindividual differences in nicotine metabolism. This review mainly summarizes recent results from our studies.

  9. Isolation and identification of androstanediol glucuronide from human plasma.

    PubMed

    Rao, P N; Burdett, J E; Moore, P H; Horton, R

    1987-11-01

    [3H]Dihydrotestosterone (50 microCi) was infused into normal men and women for 8 h. It was previously shown that this was sufficient time for this material to reach a steady state. Venous plasma was obtained at 6 and 8 h, pooled, and the unconjugated steroids removed by ether extraction. The remaining plasma was adjusted to pH 4.9 and the steroid conjugate was extracted first with ethyl acetate and then with an ether-ethanol mixture. The extracts were combined and taken to dryness. Steroid sulfates were solvolyzed using dioxane, and the mixture partitioned between ether and 1% NaOH. The aqueous phase was acidified and added to an XAD-2 column, washed with water, and the glucuronide fraction eluted with methanol. The solvent was concentrated and the methanol extract was passed through a C18 Sep-Pak, filtered through an Acrodisc CR and then subjected to gradient high performance liquid chromatography [HPLC] (Nova-Pak C18, KH2PO4, pH 3, and methanol). The fractions containing steroid glucuronides were collected and esterified with diazomethane and then acetylated with acetic anhydride in pyridine. The glucuronide triacetyl methyl ester (GAME) derivatives were then run in a second HPLC system (3 Lichrosorb 5 mu columns, 4 mm x 25 cm) using a gradient of ethanol-heptane and heptane. We clearly established that this system separates 3 alpha-diol GAME conjugated at the 17 and 3 positions (44 vs 50 min) with authentic samples previously synthesized in our laboratory. We concluded that the pooled plasma contained only the 17-GAME conjugate. No significant activity of the 3-glucuronide was detected. The natural compound in circulation, therefore, is 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide.

  10. Acetaminophen hepatotoxicity and HIF-1α induction in acetaminophen toxicity in mice occurs without hypoxia.

    PubMed

    Chaudhuri, Shubhra; McCullough, Sandra S; Hennings, Leah; Letzig, Lynda; Simpson, Pippa M; Hinson, Jack A; James, Laura P

    2011-05-01

    HIF-1α is a nuclear factor important in the transcription of genes controlling angiogenesis including vascular endothelial growth factor (VEGF). Both hypoxia and oxidative stress are known mechanisms for the induction of HIF-1α. Oxidative stress and mitochondrial permeability transition (MPT) are mechanistically important in acetaminophen (APAP) toxicity in the mouse. MPT may occur as a result of oxidative stress and leads to a large increase in oxidative stress. We previously reported the induction of HIF-1α in mice with APAP toxicity and have shown that VEGF is important in hepatocyte regeneration following APAP toxicity. The following study was performed to examine the relative contribution of hypoxia versus oxidative stress to the induction of HIF-1α in APAP toxicity in the mouse. Time course studies using the hypoxia marker pimonidazole showed no staining for pimonidazole at 1 or 2h in B6C3F1 mice treated with APAP. Staining for pimonidazole was present in the midzonal to periportal regions at 4, 8, 24 and 48h and no staining was observed in centrilobular hepatocytes, the sites of the toxicity. Subsequent studies with the MPT inhibitor cyclosporine A showed that cyclosporine A (CYC; 10mg/kg) reduced HIF-1α induction in APAP treated mice at 1 and 4h and did not inhibit the metabolism of APAP (depletion of hepatic non-protein sulfhydryls and hepatic protein adduct levels). The data suggest that HIF-1α induction in the early stages of APAP toxicity is secondary to oxidative stress via a mechanism involving MPT. In addition, APAP toxicity is not mediated by a hypoxia mechanism.

  11. Alteration in metabolism and toxicity of acetaminophen upon repeated administration in rats.

    PubMed

    Kim, Sun J; Lee, Min Y; Kwon, Do Y; Kim, Sung Y; Kim, Young C

    2009-10-01

    Our previous studies showed that administration of a subtoxic dose of acetaminophen (APAP) to female rats increased generation of carbon monoxide from dichloromethane, a metabolic reaction catalyzed mainly by cytochrome P450 (CYP) 2E1. In this study we examined the changes in metabolism and toxicity of APAP upon repeated administration. An intraperitoneal dose of APAP (500 mg/kg) alone did not increase aspartate aminotransferase, alanine aminotransferase, or sorbitol dehydrogenase activity in serum, but was significantly hepatotoxic when the rats had been pretreated with an identical dose of APAP 18 h earlier. The concentrations and disappearance of APAP and its metabolites in plasma were monitored for 8 h after the treatment. APAP pretreatment reduced the elevation of APAP-sulfate, but increased APAP-cysteine concentrations in plasma. APAP or APAP-glucuronide concentrations were not altered. Administration of a single dose of APAP 18 h before sacrifice increased microsomal CYP activities measured with p-nitrophenol, p-nitroanisole, and aminopyrine as probes. Expression of CYP2E1, CYP3A, and CYP1A proteins in the liver was also elevated significantly. The results suggest that administration of APAP at a subtoxic dose may result in an induction of hepatic CYP enzymes, thereby altering metabolism and toxicological consequences of various chemical substances that are substrates for the same enzyme system.

  12. Establishment of a model of acetaminophen-induced hepatotoxicity in different weekly-aged ICR mice.

    PubMed

    Taguchi, K; Tokuno, M; Yamasaki, K; Kadowaki, D; Seo, H; Otagiri, M

    2015-10-01

    Acetaminophen (APAP), a widely used analgesic and antipyretic drug, has the potential to cause lethal hepatotoxicity. Mice are widely used for developing murine models of APAP-induced hepatotoxicity, and many researchers have used these models for APAP-related studies including the fields of biology, pharmacology and toxicology. Although drug-induced hepatotoxicity is dependent on a number of factors (species, gender and age), very few studies have investigated the effect of aging on APAP hepatotoxicity. In this study, we evaluated the effect of age on APAP-induced hepatotoxicity in different weekly-aged mice to establish a model of APAP-induced hepatotoxicity that is an accurate reflection of general experimental conditions. Male ICR mice 4, 6, 8, 10 and 12 weeks old were given APAP intraperitoneally, and mortality, hepatic damage and the plasma concentration of APAP metabolites were evaluated. It was found that younger male ICR mice were relatively resistant to hepatotoxicity induced by intraperitoneal APAP administration. In addition, the APAP-glucuronide concentration in plasma remained essentially the same among the differently-aged mice, while APAP-sulfate levels were dramatically decreased in an age-dependent manner. Thus, it is recommended that mice of the same ages be used in studies related to APAP-induced hepatotoxixity. These results provide evidence in support of not only the age-related changes in susceptibility to APAP-derived hepatotoxicity in mice but also in developing mouse models for APAP-related studies.

  13. In Vitro Stability of Free and Glucuronidated Cannabinoids in Urine Following Controlled Smoked Cannabis

    PubMed Central

    Desrosiers, Nathalie A.; Lee, Dayong; Scheidweiler, Karl B.; Concheiro-Guisan, Marta; Gorelick, David A.; Huestis, Marilyn A.

    2014-01-01

    Analyte stability is an important factor in urine test interpretation, yet cannabinoid stability data are limited. A comprehensive study of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol, cannabinol, THC-glucuronide, and THCCOOH-glucuronide stabilities in authentic urine was completed. Urine samples after ad libitum cannabis smoking were pooled to prepare low and high pools for each study participant; baseline concentrations were measured within 24h at room temperature (RT), 4°C and −20°C. Stability at RT, 4°C and −20°C was evaluated by Friedman tests for up to 1 year. THCCOOH, THC-glucuronide, and THCCOOH-glucuronide were quantified in baseline pools. RT THCCOOH baseline concentrations were significantly higher than −20°C, but not 4°C baseline concentrations. After 1 week at RT, THCCOOH increased, THCCOOH-glucuronide decreased, but THC-glucuronide was unchanged. In RT low pool, total THCCOOH (THCCOOH+THCCOOH-glucuronide) was significantly lower after 1 week. At 4°C, THCCOOH was stable 2 weeks, THCCOOH-glucuronide 1 month and THC-glucuronide for at least 6 months. THCCOOH was stable frozen for 1 year, but 6 months high pool results were significantly higher than baseline; THC-glucuronide and THCCOOH-glucuronide were stable for 6 months. Total THCCOOH was stable 6 months at 4°C, and frozen 6 months (low) and 1 year (high). THC, cannabidiol and cannabinol were never detected in urine; although not detected initially, 11-OH-THC was detected in 2 low and 3 high pools after one week at RT. Substantial THCCOOH-glucuronide deconjugation was observed at RT and 4°C. Analysis should be conducted within 3 months if non-hydrolyzed THCCOOH or THCCOOH-glucuronide quantification is required. PMID:24292435

  14. Protective effects of hydrogen sulfide anions against acetaminophen-induced hepatotoxicity in mice.

    PubMed

    Ishii, Isao; Kamata, Shotaro; Hagiya, Yoshifumi; Abiko, Yumi; Kasahara, Tadashi; Kumagai, Yoshito

    2015-12-01

    The key mechanism for hepatotoxicity resulting from acetaminophen (APAP) overdose is cytochrome P450-dependent formation of N-acetyl-p-benzoquinone imine (NAPQI), a potent electrophilic metabolite that forms protein adducts. The fundamental roles of glutathione in the effective conjugation/clearance of NAPQI have been established, giving a molecular basis for the clinical use of N-acetylcysteine as a sole antidote. Recent evidence from in vitro experiments suggested that sulfide anions (S(2-)) to yield hydrogen sulfide anions (HS(-)) under physiological pH could effectively react with NAPQI. This study evaluated the protective roles of HS(-) against APAP-induced hepatotoxicity in mice. We utilized cystathionine γ-lyase-deficient (Cth(-/-)) mice that are highly sensitive to acetaminophen toxicity. Intraperitoneal injection of acetaminophen (150 mg/kg) into Cth(-/-) mice resulted in highly elevated levels of serum alanine/aspartate aminotransferases and lactate dehydrogenase associated with marked increases in oncotic hepatocytes; all of which were significantly inhibited by intraperitoneal preadministration of sodium hydrosulfide (NaHS). NaHS preadministration significantly suppressed APAP-induced serum malondialdehyde level increases without abrogating APAP-induced rapid depletion of hepatic glutathione. These results suggest that exogenous HS(-) protects hepatocytes by directly scavenging reactive NAPQI rather than by increasing cystine uptake and thereby elevating intracellular glutathione levels, which provides a novel therapeutic approach against acute APAP poisoning.

  15. Possible effects of repeated exposure to ibuprofen and acetaminophen on the intestinal immune response in young infants.

    PubMed

    Langhendries, J-P; Allegaert, K; Van Den Anker, J N; Veyckemans, F; Smets, F

    2016-02-01

    There has been an exponential increase in the frequency of immune deviations in young children. Consequently, research investigating environmental causes for this increase has become a Public Health priority. We have summarized the experimental observations and epidemiological data that could link repeated acetaminophen and ibuprofen exposure in early infancy to this increase. Recent observations on the maturational immunity of the intestinal sub-mucosal lamina propria underscore indeed the importance of prostaglandins (PGE2s). PGE2 appearing at this sub-mucosal level is a product of arachidonic acid metabolism mediated by type-2 cyclooxygenase (COX-2) situated on the membrane of many immune cells. Moreover, it seems that acetaminophen - like ibuprofen - also carries a non-selective inhibitory action on peripheral COXs, besides its central action. This inhibitory action of acetaminophen on COX2 only relates to physiological, low arachidonic acid concentrations. This explains the difference in anti-inflammatory effects. The impact of repeated inhibition of mucosal PGE2 synthesis due to COX-inhibitor exposure on maturational immunity has been demonstrated in animal experiments. Repeatedly exposed young animals do not develop tolerance to food antigens and exhibit autoimmune deviations. Several recent epidemiological studies have also reported on the magnitude of acetaminophen and ibuprofen exposure in children and the increase in immune deviations, it is important to better understand the potential negative impact of repeated inhibitions of prostaglandin synthesis by COX2s during infancy. Since acetaminophen and ibuprofen are commonly administered analgesics and antipyretics, a well-designed prospective strategy for pharmacovigilance and -epidemiology of COX-inhibitor exposure in infancy is urgently needed.

  16. The effect of morbid obesity on morphine glucuronidation.

    PubMed

    Lloret-Linares, Celia; Luo, Huilong; Rouquette, Alexandra; Labat, Laurence; Poitou, Christine; Tordjman, Joan; Bouillot, Jean-Luc; Mouly, Stéphane; Scherrmann, Jean-Michel; Bergmann, Jean-François; Declèves, Xavier

    2017-04-01

    The purpose of the present work was to study the change in morphine metabolic ratio in obese subjects before and after Roux-en-Y Gastric Bypass (RYGB) and to identify clinical and/or biological factors associated with this change. The pharmacokinetics (PK) of oral morphine (30mg), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) was performed in patients before (n=25; mean BMI=43.2 (35.4-61.9)kg/m(2)), 7-15days (n=16) and 6 months after RYGB (n=19; mean BMI=32.3 (25.4-46.0)kg/m(2)). Morphine Cmax and AUC0-inf were significantly increased and morphine Tmax significantly shortened at 6 months after RYGB compared with preoperative data, indicating an important increase in the rate and extent of morphine absorption. The morphine metabolic ratio 0-inf M3G+M6G/Morphine, decreased significantly from the preoperative to 6 months postoperative period with an average of -26% (range -74%; +21%; p=0.004), but not in the immediate post-operative period. The change in morphine metabolic ratio was associated with a change in BMI, fat mass in kg, and triglyceride levels (rho=0.5, p≤0.04). The degree of change in several markers of low-grade inflammation, or the level of liver steatosis and fibrosis before surgery, was not associated with the change in morphine metabolic ratios. Our findings indicate that RYGB-induced weight loss significantly decreases morphine metabolic ratio, arguing for an effect of morbid obesity on glucuronidation. With glucuronide exposure at 6 months similar to preoperative values, a higher morphine AUC0-inf should encourage reducing morphine dosage in patients undergoing RYGB and chronically receiving immediate-release oral morphine.

  17. Enzyme-assisted synthesis and structural characterization of the 3-, 8-, and 15-glucuronides of deoxynivalenol.

    PubMed

    Uhlig, Silvio; Ivanova, Lada; Fæste, Christiane Kruse

    2013-02-27

    4-Deoxynivalenol is one of the most prevalent mycotoxins in grain-based food and feed products worldwide. Conjugation of deoxynivalenol to glucuronic acid and elimination via the urine appears to be the major metabolism pathway, although with differing efficiency in different species. In order to make pure deoxynivalenol glucuronides for analytical methodologies available we intended to enzymatically synthesize glucuronides of deoxynivalenol using rat and human liver microsomes supplemented with uridine 5'-diphosphoglucuronic acid and alamethicin as detergent. Three glucuronides were isolated and purified using solid-phase extraction of microsomal incubations and subsequent semipreparative hydrophilic interaction chromatography. NMR spectra were obtained for all three compounds from solutions in methanol, showing that deoxynivalenol 3-O-β-D-glucuronide and deoxynivalenol 15-O-β-D-glucuronide were the major products from incubations of deoxynivalenol with rat and human liver microsomes, respectively. The NMR spectra of a third glucuronide showed replacement of the C-8 carbonyl by a ketal carbon. This glucuronide was finally identified as deoxynivalenol 8-O-β-D-glucuronide. The present study provides unequivocal structural evidence for three glucuronides of deoxynivalenol formed by liver enzymes.

  18. Investigation of a recently detected 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol isomer: Studies on the degradation of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol glucuronide.

    PubMed

    Hanisch, Stephanie; Paulke, Alexander; Toennes, Stefan W

    2016-09-10

    An isomer of the tetrahydrocannabinol (THC) metabolite 11-nor-9-carboxy-Δ(9)-THC (THCCOOH) had been detected in blood of cannabis users. The present study was initiated to elucidate whether the labile metabolite THCCOOH-glucuronide could be the precursor. THCCOOH-glucuronide was incubated in human serum and albumin (HSA) solution at various temperatures (-18, 4.5, 22 and 37°C) and pH values (pH 7.4 and 8.3) for seven days in the presence or absence of the esterase inhibitor sodium fluoride. Analysis of incubation samples was performed using LC-MS/MS. Marked degradation of THCCOOH-glucuronide was observed at 37°C. It was found that not only THCCOOH, but also the isomer is a degradation product of THCCOOH-glucuronide and its in-vivo production is assumed. Degradation to THCCOOH and the isomer occurred at alkaline pH, in the presence of fluoride-sensitive esterases and of HSA alone. To inhibit isomer formation during sample storage, refrigeration and controlling of the pH are recommended. However, THCCOOH and the isomer exhibit similar properties during incubations in serum, but differ in their interaction with HSA. The present study confirmed the nature of the isomer as degradation product of the abundant THC metabolite THCCOOH-glucuronide. Serum albumin and esterases are obviously involved. The isomer is formed not only during storage, but also under physiological conditions, suggesting that it can be considered an in-vivo metabolite. However, the chemical structure of the isomer remains unknown and further research is necessary.

  19. Potential role of caveolin-1 in acetaminophen-induced hepatotoxicity

    SciTech Connect

    Gardner, Carol R.; Gray, Joshua P.; Joseph, Laurie B.; Cervelli, Jessica; Bremer, Nicole; Kim, Yunjung; Mishin, Vladimir; Laskin, Jeffrey D.; Laskin, Debra L.

    2010-05-15

    Caveolin-1 (Cav-1) is a membrane scaffolding protein, which functions to regulate intracellular compartmentalization of various signaling molecules. In the present studies, transgenic mice with a targeted disruption of the Cav-1 gene (Cav-1{sup -/-}) were used to assess the role of Cav-1 in acetaminophen-induced hepatotoxicity. Treatment of wild-type mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis and increases in serum transaminases. This was correlated with decreased expression of Cav-1 in the liver. Acetaminophen-induced hepatotoxicity was significantly attenuated in Cav-1{sup -/-} mice, an effect that was independent of acetaminophen metabolism. Acetaminophen administration resulted in increased hepatic expression of the oxidative stress marker, lipocalin 24p3, as well as hemeoxygenase-1, but decreased glutathione and superoxide dismutase-1; no differences were noted between the genotypes suggesting that reduced toxicity in Cav-1{sup -/-} mice is not due to alterations in antioxidant defense. In wild-type mice, acetaminophen increased mRNA expression of the pro-inflammatory cytokines, interleukin-1beta, and monocyte chemoattractant protein-1 (MCP-1), as well as cyclooxygenase-2, while 15-lipoxygenase (15-LOX), which generates anti-inflammatory lipoxins, decreased. Acetaminophen-induced changes in MCP-1 and 15-LOX expression were greater in Cav-1{sup -/-} mice. Although expression of tumor necrosis factor-alpha, a potent hepatocyte mitogen, was up-regulated in the liver of Cav-1{sup -/-} mice after acetaminophen, expression of proliferating cell nuclear antigen and survivin, markers of cellular proliferation, were delayed, which may reflect the reduced need for tissue repair. Taken together, these data demonstrate that Cav-1 plays a role in promoting inflammation and toxicity during the pathogenesis of acetaminophen-induced injury.

  20. Acetaminophen-induced acute liver injury in HCV transgenic mice

    SciTech Connect

    Uehara, Takeki; Kosyk, Oksana; Jeannot, Emmanuelle; Bradford, Blair U.; Tech, Katherine; Macdonald, Jeffrey M.; Boorman, Gary A.; Chatterjee, Saurabh; Mason, Ronald P.; Melnyk, Stepan B.; Tryndyak, Volodymyr P.; Pogribny, Igor P.; Rusyn, Ivan

    2013-01-15

    The exact etiology of clinical cases of acute liver failure is difficult to ascertain and it is likely that various co-morbidity factors play a role. For example, epidemiological evidence suggests that coexistent hepatitis C virus (HCV) infection increased the risk of acetaminophen-induced acute liver injury, and was associated with an increased risk of progression to acute liver failure. However, little is known about possible mechanisms of enhanced acetaminophen hepatotoxicity in HCV-infected subjects. In this study, we tested a hypothesis that HCV-Tg mice may be more susceptible to acetaminophen hepatotoxicity, and also evaluated the mechanisms of acetaminophen-induced liver damage in wild type and HCV-Tg mice expressing core, E1 and E2 proteins. Male mice were treated with a single dose of acetaminophen (300 or 500 mg/kg in fed animals; or 200 mg/kg in fasted animals; i.g.) and liver and serum endpoints were evaluated at 4 and 24 h after dosing. Our results suggest that in fed mice, liver toxicity in HCV-Tg mice is not markedly exaggerated as compared to the wild-type mice. In fasted mice, greater liver injury was observed in HCV-Tg mice. In fed mice dosed with 300 mg/kg acetaminophen, we observed that liver mitochondria in HCV-Tg mice exhibited signs of dysfunction showing the potential mechanism for increased susceptibility. -- Highlights: ► Acetaminophen-induced liver injury is a significant clinical challenge. ► HCV-infected subjects may be at higher risk for acetaminophen-induced liver injury. ► We used HCV transgenics to test if liver injury due to acetaminophen is exacerbated.

  1. Separation of a BMS drug candidate and acyl glucuronide from seven glucuronide positional isomers in rat plasma via high-performance liquid chromatography with tandem mass spectrometric detection.

    PubMed

    Xue, Y-J; Simmons, Neal J; Liu, Jane; Unger, Steve E; Anderson, Danielle F; Jenkins, Rand G

    2006-01-01

    A high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for the determination of a BMS drug candidate and its acyl glucuronide (1-O-beta glucuronide) in rat plasma. A 50-microL aliquot of each plasma sample was fortified with acetonitrile containing the internal standard to precipitate proteins and extract the analytes of interest. After mixing and centrifugation, the supernatant from each sample was transferred to a 96-well plate and injected into an LC/MS/MS system. Chromatographic separation was achieved isocratically on a Phenomenex Luna C(18), 3 mm x 150 mm, 3 microm column. The mobile phase contained 0.075% formic acid in 70:30 (v/v) acetonitrile/water. Under the optimized chromatographic conditions, the BMS drug candidate and its acyl glucuronide were separated from its seven glucuronide positional isomers within 10 min. Resolution of the parent from all glucuronides and acyl glucuronide from its positional isomers was critical to avoid their interference with quantitation of parent or acyl glucuronide. Detection was by positive ion electrospray MS/MS on a Sciex API 4000. The standard curve, which ranged from 5 to 5000 ng/mL, was fitted to a 1/x(2) weighted quadratic regression model for both the BMS drug candidate and its acyl glucuronide. Whole blood and plasma stability experiments were conducted to establish the sample collection, storage, and processing conditions. The validation results demonstrated that this method was rugged and repeatable. The same methodology has also been used in mouse and human plasma for the determination of the BMS drug candidate and its acyl glucuronide.

  2. Interaction of hesperetin glucuronide conjugates with human BCRP, MRP2 and MRP3 as detected in membrane vesicles of overexpressing baculovirus-infected Sf9 cells.

    PubMed

    Brand, Walter; Oosterhuis, Berend; Krajcsi, Peter; Barron, Denis; Dionisi, Fabiola; van Bladeren, Peter J; Rietjens, Ivonne M C M; Williamson, Gary

    2011-12-01

    The citrus flavonoid hesperetin (4'-methoxy-3',5,7-trihydroxyflavanone) is the aglycone of hesperidin, the major flavonoid present in sweet oranges. Hesperetin 7-O-glucuronide (H7G) and hesperetin 3'-O-glucuronide (H3'G) are the two most abundant metabolites of hesperetin in vivo. In this study, their interaction with specific ABC transporters, believed to play a role in the disposition and bioavailability of hesperetin, was studied using Sf9 membranes from cells overexpressing human BCRP (ABCG2), MRP2 (ABCC2) and MRP3 (ABCC3). Both H7G and H3'G were tested for their potential to activate and inhibit ATPase activity, and to inhibit vesicular transport by these transporters. Both H7G and H3'G demonstrated interaction with all tested ABC transporters, especially with BCRP and MRP3. An interesting difference between H7G and H3'G was seen with respect to the interaction with BCRP: H7G stimulated the ATPase activity of BCRP up to 76% of the maximal effect generated by the reference activator sulfasalazine, with an EC(50) of 0.45 µM, suggesting that H7G is a high affinity substrate of BCRP, whereas H3'G did not stimulate BCRP ATPase activity. Only moderate inhibition of BCRP ATPase activity at high H3'G concentrations was observed. This study provides information on the potential of hesperetin glucuronide conjugates to act as specific ABC transporter substrates or inhibitors and indicates that regio-specific glucuronidation could affect the disposition of hesperetin.

  3. Acitretin exhibits inhibitory effects towards UDP-glucuronosyltransferase (UGT)1A9-mediated 4-methylumbelliferone (4-MU) and propofol glucuronidation reaction.

    PubMed

    Yu, Ming-Lian; Yang, Yue; Wang, Cong-Min; Zhang, Meng-Meng; Bai, Miao-Chun; Guo, Yue-Ling

    2013-06-01

    The present study aimed to evaluate the potential risk of drug-drug interactions associated with acitretin which is a drug for therapy of psoriasis approved by the Food and Drug Administration (FDA). The initial screening of acitretin's inhibition towards 4-methylumbelliferone (4-MU) glucuronidation catalyzed by important UDP-glucuronosyltransferase (UGT) isoforms in the liver showed that UGT1A9 activity was strongly inhibited by acitretin with other UGT isoforms negligibly influenced. The inhibition type is best fit to competitive inhibition, and the inhibition kinetic parameter (K(i)) was determined to be 3.5 microM. The inhibition behaviour of acitretin towards UGT1A9 activity did not exhibit probe substrate-dependent behaviour when selecting human liver microsomes (HLMs)-catalyzed propofol-O-glucuronidation as probe reaction of UGT1A9. The same inhibition type and similar inhibition parameters (K(i) = 3.2 microM) were obtained. Using the maximum plasma exposure dose of acitretin (C(max)), the C(max)/K(i) values were calculated to be 0.23 and 0.25 when selecting 4-MU and propofol as probe substrates, respectively. All these results indicate a potential clinical drug-drug interaction between acitretin and 4-MU or propofol.

  4. Chitohexaose protects against acetaminophen-induced hepatotoxicity in mice

    PubMed Central

    Barman, P K; Mukherjee, R; Prusty, B K; Suklabaidya, S; Senapati, S; Ravindran, B

    2016-01-01

    Acetaminophen (N-acetyl-para-aminophenol (APAP)) toxicity causes acute liver failure by inducing centrilobular hepatic damage as a consequence of mitochondrial oxidative stress. Sterile inflammation, triggered by hepatic damage, facilitates gut bacterial translocation leading to systemic inflammation; TLR4-mediated activation by LPS has been shown to have a critical role in APAP-mediated hepatotoxicity. In this study, we demonstrate significant protection mediated by chitohexaose (Chtx) in mice challenged with a lethal dose of APAP (400 mg/kg b.w.). Decreased mortality by Chtx was associated with reduced hepatic damage, increased peritoneal migration of neutrophils, decreased mRNA expression of IL-1β as well as inhibition of inflammasome activation in liver. Further, an alternate mouse model of co-administration of a sublethal doses of APAP (200 mg/kg b.w.) and LPS (5 mg/kg b.w.) operating synergistically and mediating complete mortality was developed. Overwhelming inflammation, characterized by increased inflammatory cytokines (TNF-α, IL-1β and so on) in liver as well as in circulation and mortality was demonstrable in this model. Also, Chtx administration mediated significant reversal of mortality in APAP+LPS co-administered mice, which was associated with reduced IL-1β in liver and plasma cytokines in this model. In conclusion, Chtx being a small molecular weight linear carbohydrate offers promise for clinical management of liver failure associated with APAP overdose. PMID:27171266

  5. Protective effects of diallyl sulfide on acetaminophen-induced toxicities.

    PubMed

    Hu, J J; Yoo, J S; Lin, M; Wang, E J; Yang, C S

    1996-10-01

    Diallyl sulfide (DAS), a major flavour component of garlic, is known to modulate drug metabolism and may protect animals from chemically induced toxicity and carcinogenesis. In this study the effects of DAS on the oxidative metabolism and hepatotoxicity induced by acetaminophen (APAP) in rats were investigated. In the hepatotoxicity evaluation of Fischer 344 rats there was a dose-dependent increase in the odds of mortality rate by APAP (P = 0.009); DAS treatment significantly protected rats from APAP-related mortality (P = 0.026). Liver toxicity determined by lactate dehydrogenase activity was significantly increased by APAP treatment (0.75 g/kg). Pretreatment with DAS protected animals from APAP-induced liver toxicity in a time- and dose-dependent fashion. Treatment of DAS (50 mg/kg) 3 hr after APAP dosing significantly (P < 0.05) protected rats from APAP-induced liver toxicity. The metabolism of APAP (50 microM) in vitro was significantly inhibited by DAS (0.3-1 mM) in liver microsomes isolated from F344 rats. As the effect of DAS on APAP-induced hepatotoxicity in vivo was observed only when DAS was administered before or shortly after (< 3 hr) APAP dosing, data suggested that the protective effect of DAS is mainly at the metabolic activation step of APAP. However, the possibility that DAS may also have effects on other drug metabolism systems, such as glutathione (GSH) and glutathione S-transferases, cannot be ruled out.

  6. NQO2 is a reactive oxygen species generating off-target for acetaminophen.

    PubMed

    Miettinen, Teemu P; Björklund, Mikael

    2014-12-01

    The analgesic and antipyretic compound acetaminophen (paracetamol) is one of the most used drugs worldwide. Acetaminophen overdose is also the most common cause for acute liver toxicity. Here we show that acetaminophen and many structurally related compounds bind quinone reductase 2 (NQO2) in vitro and in live cells, establishing NQO2 as a novel off-target. NQO2 modulates the levels of acetaminophen derived reactive oxygen species, more specifically superoxide anions, in cultured cells. In humans, NQO2 is highly expressed in liver and kidney, the main sites of acetaminophen toxicity. We suggest that NQO2 mediated superoxide production may function as a novel mechanism augmenting acetaminophen toxicity.

  7. Acetaminophen induced Steven Johnson syndrome-toxic epidermal necrolysis overlap.

    PubMed

    Khawaja, Ali; Shahab, Ahmed; Hussain, Syed Ather

    2012-05-01

    Steven Johnson Syndrome and Toxic Epidermal Necrolysis are rare but severe form of hypersensitivity inflammatory reactions to multiple offending agents including drugs. Acetaminophen is extensively used due to its analgesic and anti-pyretic properties. It is rendered to be relatively safe, with hepatotoxicity considered to be the major adverse effect. However, very few cases of Steven Johnson Syndrome and Toxic Epidermal Necrolysis have been reported with acetaminophen usage in the past. We present the case of a 40 years old lady who developed an overlap of the two condition after taking several doses of acetaminophen for fever. She presented with widespread maculopapular rash, stinging in the eyes, oral mucosal ulcerations and high grade fever. She was successfully treated with corticosteroid therapy along with the supportive treatment. This case addresses the fact, that severe hypersensitivity reactions can occur with acetaminophen which can be potentially life threatening.

  8. Careful: Acetaminophen in Pain Relief Medicines Can Cause Liver Damage

    MedlinePlus

    ... Careful: Acetaminophen in pain relief medicines can cause liver damage Share Tweet Linkedin Pin it More sharing ... word or may have the abbreviation "APAP." Severe liver damage may occur and may lead to death ...

  9. Evidence for an UDP-glucuronic acid/phenol glucuronide antiport in rat liver microsomal vesicles.

    PubMed

    Bánhegyi, G; Braun, L; Marcolongo, P; Csala, M; Fulceri, R; Mandl, J; Benedetti, A

    1996-04-01

    The transport of glucuronides synthesized in the luminal compartment of the endoplasmic reticulum by UDP-glucuronosyltransferase isoenzymes was studied in rat liver microsomal vesicles. Microsomal vesicles were loaded with p-nitrophenol glucuronide (5 mM), phenolphthalein glucuronide or UDP-glucuronic acid, by a freeze-thawing method. In was shown that: (i) the loading procedure resulted in millimolar intravesicular concentrations of the different loading compounds; (ii) addition of UDP-glucuronic acid (5 mM) to the vesicles released both intravesicular glucuronides within 1 min; (iii) glucuronides stimulated the release of UDP-glucuronic acid from UDP acid-loaded microsomal vesicles; (iv) trans-stimulation of UDP-glucuronic acid entry by loading of microsomal vesicles with p-nitrophenol glucuronide, phenolphthalein glucuronide, UDP-glucuronic acid and UDP-N-acetyl-glucosamine almost completely abolished the latency of UDP-glucuronosyltransferase, although mannose 6-phosphatase latency remained unaltered; (v) the loading compounds by themselves did not stimulate UDP-glucuronosyltransferase activity. This study indicates that glucuronides synthesized in the lumen of endoplasmic reticulum can leave by an antiport, which concurrently transports USP-glucuronic acid into the lumen of the endoplasmic reticulum.

  10. UDP-glucuronosyltransferases 1A6 and 1A10 catalyze reduced menadione glucuronidation

    SciTech Connect

    Nishiyama, Takahito; Ohnuma, Tomokazu; Inoue, Yuu; Kishi, Takehiko; Ogura, Kenichiro; Hiratsuka, Akira

    2008-06-27

    Menadione (2-methyl-1,4-naphthoquine), also known as vitamin K3, has been widely used as a model compound in the field of oxidative stress-related research. The metabolism of menadione has been studied, and it is known that menadione undergoes a two-electron reduction by NAD(P)H:Quinone oxidoreductase 1 (NQO1) after which the reduced form of menadione (2-methyl-1,4-naphthalenediol, menadiol) is glucuronidated and excreted in urine. To investigate which human UDP-glucuronosyltransferase (UGT) isoforms participate in the glucuronidation of menadiol reduced by NQO1 from menadione, we first constructed heterologously expressed NQO1 in Sf9 cells and tested the menadiol glucuronidating activity of 16 human recombinant UGT isoforms. Of the 16 UGT isoforms, UGTs 1A6, 1A7, 1A8, 1A9, and 1A10 catalyzed menadiol glucuronidation, and, of these, UGTs 1A6 and 1A10 catalyzed menadiol glucuronidation at much higher rates than the other UGTs. Menadiol was regioselectively glucuronidated in the manner of 4-position > 1-position by UGTs 1A7, 1A8, 1A9, and 1A10. In contrast to these UGTs, only UGT1A6 exhibited 1-menadiol-preferential glucuronidating activity. The results suggest possible detoxification pathways for quinones via NQO1 reduction followed by UGT glucuronidation.

  11. Effect of acetaminophen on sulfamethazine acetylation in male volunteers.

    PubMed

    Tahir, I M; Iqbal, T; Saleem, S; Mehboob, H; Akhter, N; Riaz, M

    2016-03-01

    The effect of acetaminophen on sulfamethazine N-acetylation by human N-acetyltrasferase-2 (NAT2) was studied in 19 (n=19) healthy male volunteers in two different phases. In the first phase of the study the volunteers were given an oral dose of sulfamethazine 500 mg alone and blood and urine samples were collected. After the 10-day washout period the same selected volunteers were again administered sulfamethazine 500 mg along with 1000 mg acetaminophen. The acetylation of sulfamethazine by human NAT2 in both phases with and without acetaminophen was determined by HPLC to establish their respective phenotypes. In conclusion obtained statistics of present study revealed that acetaminophen significantly (P<0.0001) decreased sulfamethazine acetylation in plasma of both slow and fast acetylator male volunteers. A highly significant (P<0.0001) decrease in plasma-free and total sulfamethazine concentration was also observed when acetaminophen was co-administered. Urine acetylation status in both phases of the study was found not to be in complete concordance with that of plasma. Acetaminophen significantly (P<0.0001) increased the acetyl, free and total sulfamethazine concentration in urine of both slow and fast acetylators. Urine acetylation analysis has not been found to be a suitable approach for phenotypic studies.

  12. Acetaminophen for Chronic Pain: A Systematic Review on Efficacy.

    PubMed

    Ennis, Zandra Nymand; Dideriksen, Dorthe; Vaegter, Henrik Bjarke; Handberg, Gitte; Pottegård, Anton

    2016-03-01

    Acetaminophen (paracetamol) is the most commonly used analgesic worldwide and recommended as first-line treatment in all pain conditions by WHO. We performed a systematic literature review to evaluate the efficacy of acetaminophen when used for chronic pain conditions. Applying three broad search strategies for acetaminophen use in chronic pain in both Embase and PubMed, 1551 hits were obtained. After cross-reference searches of both trials and 38 reviews, seven studies comparing acetaminophen in continuous dosing regimens of more than 2 weeks with placebo were included. The review was conducted according to the PRISMA guidelines. All studies were conducted in patients with hip- or knee osteoarthritis and six of seven studies had observation periods of less than 3 months. All included studies showed no or little efficacy with dubious clinical relevance. In conclusion, there is little evidence to support the efficacy of acetaminophen treatment in patients with chronic pain conditions. Assessment of continuous efficacy in the many patients using acetaminophen worldwide is recommended.

  13. Direct measurement of salicylphenolic glucuronide in human urine.

    PubMed

    Imhoff, D M; Reece, P A; Dimitriadis, E; Ward, A D; Bochner, F

    1986-01-01

    Indirect measurement of salicylphenolic glucuronide (SPG) has suggested that the formation of this metabolite from therapeutic doses of salicyclic acid (SA) is capacity-limited in humans. A direct high performance liquid chromatographic (HPLC) assay for SPG in human urine is described. SPG was prepared by a published method and purified by HPLC. On treatment with beta-glucuronidase, SPG yielded the expected amount of SA. Spectroscopic data, melting point, and optical rotation of the glucuronide and/or its triacetyl dimethyl ester derivative were consistent with the proposed structure. SPG was assayed using a 5-micron C18 column (temperature 55 degrees C) and fluorescence detection. A nonlinear gradient mobile phase at a flow rate of 2 ml/min was used, beginning with 100% 0.1 M pH 2.1 phosphate buffer and finishing with 84% buffer, 16% acetonitrile. Total run time was 25 min. Urine (10 microliter) was injected directly on the column, and quantitation was performed using urine standards. Within-run precision for SPG ranged from 1.2% at 150 mg/L to 2.4% at 5 mg/L. The limit of detection was less than 1 mg/L. A pilot study in two volunteers, each receiving a single 500-mg dose of sodium salicylate, was carried out to validate the usefulness of the assay.

  14. Acetaminophen Induces Apoptosis in Rat Cortical Neurons

    PubMed Central

    Posadas, Inmaculada; Santos, Pablo; Blanco, Almudena; Muñoz-Fernández, Maríangeles; Ceña, Valentín

    2010-01-01

    Background Acetaminophen (AAP) is widely prescribed for treatment of mild pain and fever in western countries. It is generally considered a safe drug and the most frequently reported adverse effect associated with acetaminophen is hepatotoxicity, which generally occurs after acute overdose. During AAP overdose, encephalopathy might develop and contribute to morbidity and mortality. Our hypothesis is that AAP causes direct neuronal toxicity contributing to the general AAP toxicity syndrome. Methodology/Principal Findings We report that AAP causes direct toxicity on rat cortical neurons both in vitro and in vivo as measured by LDH release. We have found that AAP causes concentration-dependent neuronal death in vitro at concentrations (1 and 2 mM) that are reached in human plasma during AAP overdose, and that are also reached in the cerebrospinal fluid of rats for 3 hours following i.p injection of AAP doses (250 and 500 mg/Kg) that are below those required to induce acute hepatic failure in rats. AAP also increases both neuronal cytochrome P450 isoform CYP2E1 enzymatic activity and protein levels as determined by Western blot, leading to neuronal death through mitochondrial–mediated mechanisms that involve cytochrome c release and caspase 3 activation. In addition, in vivo experiments show that i.p. AAP (250 and 500 mg/Kg) injection induces neuronal death in the rat cortex as measured by TUNEL, validating the in vitro data. Conclusions/Significance The data presented here establish, for the first time, a direct neurotoxic action by AAP both in vivo and in vitro in rats at doses below those required to produce hepatotoxicity and suggest that this neurotoxicity might be involved in the general toxic syndrome observed during patient APP overdose and, possibly, also when AAP doses in the upper dosing schedule are used, especially if other risk factors (moderate drinking, fasting, nutritional impairment) are present. PMID:21170329

  15. Comparison of the Drug-Drug Interactions Potential of Erlotinib and Gefitinib via Inhibition of UDP-Glucuronosyltransferases

    PubMed Central

    Liu, Yong; Ramírez, Jacqueline; House, Larry

    2010-01-01

    We aimed to investigate and compare the effects of erlotinib and gefitinib on UDP-glucuronosyltransferase (UGT) activities and to quantitatively evaluate their drug-drug interaction (DDI) potential due to UGT inhibition. The inhibitory effects of erlotinib and gefitinib on UGTs were determined using high-performance liquid chromatography by measuring the formation rates for 4-methylumbelliferone (4-MU) glucuronide, imipramine N-glucuronide, and bilirubin glucuronides using recombinant human UGT isoforms and human liver microsomes (HLMs) in the absence or presence of erlotinib and gefitinib. Inhibition kinetic studies were conducted. Area under the curve (AUC) ratios were used to predict the risk of potential DDI in vivo. Erlotinib exhibited selective potent competitive inhibition against 4-MU glucuronidation by UGT1A1, and gefitinib demonstrated a wide range of inhibition against UGT-mediated 4-MU glucuronidation, particularly against UGT1A1, UGT1A7, UGT1A9, and UGT2B7. Erlotinib also exerted potent mixed inhibition against bilirubin glucuronidation in HLMs. We estimated that coadministration of erlotinib at 100 mg/day or higher doses may result in at least a 30% increase in the AUC of drugs predominantly cleared by UGT1A1. Thus, the coadministration of erlotinib with drugs primarily cleared by UGT1A1 may result in potential DDI. In contrast, gefitinib is unlikely to cause a clinically significant DDI through inhibition of glucuronidation. PMID:19850672

  16. A Novel Resolvin-Based Strategy for Limiting Acetaminophen Hepatotoxicity

    PubMed Central

    Patel, Suraj J; Luther, Jay; Bohr, Stefan; Iracheta-Vellve, Arvin; Li, Matthew; King, Kevin R; Chung, Raymond T; Yarmush, Martin L

    2016-01-01

    Objectives: Acetaminophen (APAP)-induced hepatotoxicity is a major cause of morbidity and mortality. The current pharmacologic treatment for APAP hepatotoxicity, N-acetyl cysteine (NAC), targets the initial metabolite-driven injury but does not directly affect the host inflammatory response. Because of this, NAC is less effective if given at later stages in the disease course. Resolvins, a novel group of lipid mediators shown to attenuate host inflammation, may be a therapeutic intervention for APAP hepatotoxicity. Methods: The temporal patterns of liver injury and neutrophil activation were investigated in a murine model of APAP hepatotoxicity. In addition, the effect of neutrophil depletion and resolvin administration on the severity of liver injury induced by APAP was studied. In vitro studies to investigate the mechanism of resolvin effect on hepatocyte injury and neutrophil adhesion were performed. Results: We demonstrate that hepatic neutrophil activation occurs secondary to the initial liver injury induced directly by APAP. We also show that neutrophil depletion attenuates APAP-induced liver injury, and administration of resolvins hours after APAP challenge not only attenuates liver injury, but also extends the therapeutic window eightfold compared to NAC. Mechanistic in vitro analysis highlights resolvins' ability to inhibit neutrophil attachment to endothelial cells in the presence of the reactive metabolite of APAP. Conclusions: This study highlights the ability of resolvins to protect against APAP-induced liver injury and extend the therapeutic window compared to NAC. Although the mechanism for resolvin-mediated hepatoprotection is likely multifactorial, inhibition of neutrophil infiltration and activation appears to play an important role. PMID:26986653

  17. Macrophage activation by factors released from acetaminophen-injured hepatocytes: Potential role of HMGB1

    SciTech Connect

    Dragomir, Ana-Cristina; Laskin, Jeffrey D.; Laskin, Debra L.

    2011-06-15

    Toxic doses of acetaminophen (AA) cause hepatocellular necrosis. Evidence suggests that activated macrophages contribute to the pathogenic process; however, the factors that activate these cells are unknown. In these studies, we assessed the role of mediators released from AA-injured hepatocytes in macrophage activation. Treatment of macrophages with conditioned medium (CM) collected 24 hr after treatment of mouse hepatocytes with 5 mM AA (CM-AA) resulted in increased production of reactive oxygen species (ROS). Macrophage expression of heme oxygenase-1 (HO-1) and catalase mRNA was also upregulated by CM-AA, as well as cyclooxygenase (COX)-2 and 12/15-lipoxygenase (LOX). CM-AA also upregulated expression of the proinflammatory chemokines, MIP-1{alpha} and MIP-2. The effects of CM-AA on expression of COX-2, MIP-1{alpha} and MIP-2 were inhibited by blockade of p44/42 MAP kinase, suggesting a biochemical mechanism mediating macrophage activation. Hepatocytes injured by AA were found to release HMGB1, a potent macrophage activator. This was inhibited by pretreatment of hepatocytes with ethyl pyruvate (EP), which blocks HMGB1 release. EP also blocked CM-AA induced ROS production and antioxidant expression, and reduced expression of COX-2, but not MIP-1{alpha} or MIP-2. These findings suggest that HMGB1 released by AA-injured hepatocytes contributes to macrophage activation. This is supported by our observation that expression of the HMGB1 receptor RAGE is upregulated in macrophages in response to CM-AA. These data indicate that AA-injured hepatocytes contribute to the inflammatory environment in the liver through the release of mediators such as HMGB1. Blocking HMGB1/RAGE may be a useful approach to limiting classical macrophage activation and AA-induced hepatotoxicity. - Research Highlights: > These studies analyze macrophage activation by mediators released from acetaminophen-damaged hepatocytes. > Factors released from acetaminophen-injured hepatocytes induce

  18. A perspective on the epidemiology of acetaminophen exposure and toxicity in the United States.

    PubMed

    Blieden, Marissa; Paramore, L Clark; Shah, Dhvani; Ben-Joseph, Rami

    2014-05-01

    Acetaminophen is a commonly-used analgesic in the US and, at doses of more than 4 g/day, can lead to serious hepatotoxicity. Recent FDA and CMS decisions serve to limit and monitor exposure to high-dose acetaminophen. This literature review aims to describe the exposure to and consequences of high-dose acetaminophen among chronic pain patients in the US. Each year in the US, approximately 6% of adults are prescribed acetaminophen doses of more than 4 g/day and 30,000 patients are hospitalized for acetaminophen toxicity. Up to half of acetaminophen overdoses are unintentional, largely related to opioid-acetaminophen combinations and attempts to achieve better symptom relief. Liver injury occurs in 17% of adults with unintentional acetaminophen overdose.

  19. Trans-stilbene oxide administration increased hepatic glucuronidation of morphine but decreased biliary excretion of morphine glucuronide in rats

    SciTech Connect

    Fuhrman-Lane, C.; Fujimoto, J.M.

    1982-09-01

    The effect of the inducing agent trans-stilbene oxide (TSO) on the metabolism and biliary excretion of (/sup 14/C)morphine was studied in the isolated in situ perfused rat liver. After administration of morphine by intraportal injection or by the segmented retrograde intrabiliary injection technique, the TSO-treated group showed a marked decrease in the biliary recovery of morphine as its glucuronide conjugate (morphine-3-glucuronide (MG)). However, recovery of MG in the venous outflow of the single pass perfusate was greatly increased. These findings suggested that TSO treatment enhanced the formation of MG from morphine and changed the primary route of hepatic elimination of MG. TSO treatment also decreased the excretion of morphine (as MG) in the bile of anesthetized renal-ligated rats. This decreased biliary function required several days to develop and appeared closely associated with the inductive effect of TSO. After i.v. administration of (/sup 14/C)MG itself, biliary recovery was also markedly decreased in TSO-treated rats. It is postulated that the effect of the TSO treatment led to either a decrease in canalicular transport of MG into bile or an increase in the efficiency of transfer of MG to the blood at the sinusoidal side of the hepatocyte. Regardless of the mechanism, the results indicate the need to study compartmentalization of drug transport and metabolism functions.

  20. Confusion: acetaminophen dosing changes based on NO evidence in adults.

    PubMed

    Krenzelok, Edward P; Royal, Mike A

    2012-06-01

    Acetaminophen (paracetamol) plays a vital role in American health care, with in excess of 25 billion doses being used annually as a nonprescription medication. Over 200 million acetaminophen-containing prescriptions, usually in combination with an opioid, are dispensed annually. While acetaminophen is recognized as a safe and effective analgesic and antipyretic, it is also associated with significant morbidity and mortality (hepatotoxicity) if doses in excess of the therapeutic amount are ingested inappropriately. The maximum daily therapeutic dose of 3900-4000 mg was established in separate actions in 1977 and 1988, respectively, via the Food and Drug Administration (FDA) monograph process for nonprescription medications. The FDA has conducted multiple advisory committee meetings to evaluate acetaminophen and its safety profile, and has suggested (but not mandated) a reduction in the maximum daily dosage from 3900-4000 mg to 3000-3250 mg. In 2011, McNeil, the producer of the Tylenol® brand of acetaminophen, voluntarily reduced the maximum daily dose of its 500 mg tablet product to 3000 mg/day, and it has pledged to change the labeling of its 325 mg/tablet product to reflect a maximum of 3250 mg/day. Generic manufacturers have not changed their dosing regimens and they have remained consistent with the established monograph dose. Therefore, confusion will be inevitable as both consumers and health care professionals try to determine the proper therapeutic dose of acetaminophen. Which is the correct dose of acetaminophen: 3000 mg if 500 mg tablets are used, 3250 mg with 325 mg tablets, or 3900 mg when 650 mg arthritis-strength products are used?

  1. Rectal administration of nicomorphine in patients improves biological availability of morphine and its glucuronide conjugates.

    PubMed

    Koopman-Kimenai, P M; Vree, T B; Booij, L H; Dirksen, R

    1994-12-02

    The pharmacokinetics of 30 mg nicomorphine after rectal administration with a suppository are described in 8 patients under combined general and epidural anaesthesia. No nicomorphine or 6-mononicotinoylmorphine could be detected in the serum. Morphine appeared almost instantaneously with a lag-time of 8 min and had a final elimination half-life of 1.48 +/- 0.48 h. Morphine was metabolized to morphine-3-glucuronide and morphine-6-glucuronide. These glucuronide conjugates appeared after a lag-time of 12 min and the half-life of these two glucuronide conjugates was similar: about 2.8 h (P > 0.8). The glucuronide conjugate of 6-mononicotinoylmorphine was not detected. In the urine only morphine and its glucuronides were found. The renal clearance value for morphine was 162 ml.min-1 and for the glucuronides 81 ml.min-1. This study shows that administration of a suppository with 30 mg nicomorphine gives an excellent absolute bioavailability of morphine and its metabolites of 88%. The lipid-soluble prodrug nicomorphine is quickly absorbed and immediately hydrolysed to morphine.

  2. Elucidation of the Mechanisms through Which the Reactive Metabolite Diclofenac Acyl Glucuronide Can Mediate Toxicity

    PubMed Central

    Scialis, Renato J.

    2016-01-01

    We have previously reported that mice lacking the efflux transporter Mrp3 had significant intestinal injury after toxic diclofenac (DCF) challenge, and proposed that diclofenac acyl glucuronide (DCF-AG), as a substrate of Mrp3, played a part in mediating injury. Since both humans and mice express the uptake transporter OATP2B1 in the intestines, OATP2B1 was characterized for DCF-AG uptake. In vitro assays using human embryonic kidney (HEK)-OATP2B1 cells demonstrated that DCF-AG was a substrate with a maximal velocity (Vmax) and Km of 17.6 ± 1.5 pmol/min per milligram and 14.3 ± 0.1 μM, respectively. Another key finding from our in vitro assays was that DCF-AG was more cytotoxic compared with DCF, and toxicity occurred within 1–3 hours of exposure. We also report that 1 mM DCF-AG caused a 6-fold increase in reactive oxygen species (ROS) by 3 hours. Investigation of oxidative stress through inhibition of superoxide dismutase (SOD) revealed that DCF-AG had 100% inhibition of SOD at the highest tested dose of 1 mM. The SOD and ROS results strongly suggest DCF-AG induced oxidative stress in vitro. Lastly, DCF-AG was screened for pharmacologic activity against COX-1 and COX-2 and was found to have IC50 values of 0.620 ± 0.105 and 2.91 ± 0.36 μM, respectively, which represents a novel finding. Since cyclooxygenase (COX) inhibition can lead to intestinal ulceration, it is plausible that DCF-AG can also contribute to enteropathy via COX inhibition. Taken in context, the work presented herein demonstrated the multifactorial pathways by which DCF-AG can act as a direct contributor to toxicity following DCF administration. PMID:26869668

  3. Reversible binding of tolmetin, zomepirac, and their glucuronide conjugates to human serum albumin and plasma.

    PubMed

    Ojingwa, J C; Spahn-Langguth, H; Benet, L Z

    1994-02-01

    Acyl glucuronides of drugs and bilirubin have been shown in the past decade to be reactive metabolites undergoing acyl migration and irreversible binding. The latter reaction has been hypothesized to be facilitated by or to proceed through the formation of a reversible complex. Furthermore, it has been suggested that the decreased binding seen in patients with compromised excretory function may be due to competition by elevated plasma concentrations of the glucuronides. In these reversible binding studies, we characterized the extent and the "site" of binding of tolmetin, zomepirac, their glucuronides and isomeric conjugates. We also examined the displacement between the parent drugs and their glucuronide conjugates using a rapid ultrafiltration method. Tolmetin exhibited three classes of binding sites with a primary association constant of 1.7 x 10(6) M-1 (Kd1 = 0.60 microM). The primary association constant of zomepirac (1.16 x 10(6) M-1, Kd1 = 0.86 microM) is similar to that of tolmetin. The beta 1 and alpha/beta 3 glucuronides of both compounds bind to a lesser extent than their parent aglycones. The isomeric glucuronide conjugates of both compounds showed much stronger binding than the beta/1 conjugates. Of the four glucuronides investigated, tolmetin glucuronide-alpha/beta 3 isomer was bound by fatty acid free human serum albumin with the highest affinity (4.6 x 10(5) M-1, Kd = 2.22 microM). Protein binding of the parent drugs and conjugates were decreased significantly at pH 5.0. In displacement studies, except for salicylate and acetylsalicylate, drugs known to bind to Sites I and II as well as the digitoxin and tamoxifen binding sites had little inhibitory effect on the binding of tolmetin, zomepirac, and their glucuronide conjugates.

  4. Beta-glucuronidase is not required for transfer of [3H]-estrone-[14C]glucuronide across guinea pig fetal membranes.

    PubMed

    Goldhawk, D E; Hobkirk, R

    1998-07-01

    To understand the means whereby a charged, estrogen conjugate may be transferred across guinea pig amnion and chorion, the permeability to [3H]estrone-[14C]glucuronide was examined at 45 days and near term. No evidence of deconjugation was obtained in either early or late amnion, despite significantly greater transfer near term. Early amnion was virtually impermeable, regardless of ATP depletion. In contrast, early chorion transferred estrone-glucuronide without any requirement for deconjugation or ATP. No effect of tissue orientation was observed in amnion; whereas, incubations from maternal to fetal side of late chorion exhibited beta-glucuronidase activity. Inhibition of the latter demonstrated that hydrolysis was concomitant with but not required for transport. [3H]Estrone produced by deconjugation was enzymatically reduced after pubic symphysis relaxation, although beta-glucuronidase activity began prior to this stage. Transport across late fetal membranes was not saturable and chorion incubations from maternal to fetal side demonstrated a lower transport capacity. In either tissue orientation, late chorion displayed a lower rate of transfer than amnion. These results indicate that fetal membranes possess distinct abilities for transferring intact estrone-glucuronide, depending on stage of development and tissue orientation. The passive nature of transport and its dependence on structural characteristics is consistent with possible regulation of tight junctions.

  5. Gas chromatographic-mass spectrometric assay for 6-hydroxymelatonin sulfate and 6-hydroxymelatonin glucuronide in urine

    SciTech Connect

    Francis, P.L.; Leone, A.M.; Young, I.M.; Stovell, P.; Silman, R.E.

    1987-04-01

    Circulating melatonin is hydroxylated to 6-hydroxymelatonin and excreted in urine as the sulfate and glucuronide conjugates. We extracted these two compounds from urine by using octadecylsilane-bonded silica cartridges to eliminate most of the urea and electrolytes, and silica cartridges to separate the sulfate and glucuronide conjugates. After hydrolyzing the separated conjugates enzymically, we determined the free hydroxymelatonin by gas chromatography-mass spectrometry. Though recoveries were low and variable, we were able to quantify the analyte in the original sample by adding deuterated sulfate and glucuronide conjugates to the urines before extraction.

  6. Glucuronidation and Sulfation Kinetics of Diflunisal in Man.

    NASA Astrophysics Data System (ADS)

    Loewen, Gordon Rapheal

    Diflunisal is a nonsteroidal anti-inflammatory drug used in the treatment of arthritis and musculoskeletal pain. Diflunisal exhibits concentration- and dose-dependent kinetics, the mechanism of which has not been determined. The purpose of this study was to determine the mechanism(s) responsible for non-linear disposition of diflunisal and to examine environmental factors which may affect the elimination of diflunisal. The metabolites of diflunisal, including a new metabolite, the sulphate conjugate, were purified by column and semi-preparative high pressure liquid chromatography. Assays for the quantitation of diflunisal and conjugates in urine and diflunisal in plasma were developed. Plasma protein binding of diflunisal in blank plasma and in plasma obtained following multiple doses of diflunisal was determined by equilibrium dialysis. Total body clearance of diflunisal decreased when dose increased from 100 to 750 mg. Total clearance increased when dose increased from 750 to 1000 mg. The percent of recovered dose eliminated as the acyl glucuronide decreased and the percent eliminated as the sulphate increased with increasing dose of diflunisal. Plasma protein binding of diflunisal was concentration dependent over a range of diflunisal plasma concentrations of 3 to 257 mug/ml. Total clearance, and to a lesser degree, unbound clearance of diflunisal were decreased following multiple dose administration of 250 and 500 mg diflunisal. Percent of recovered dose eliminated as the acyl glucuronide decreased and percent eliminated as the sulphate conjugate increased following multiple dosing. Plasma protein binding of diflunisal was similar in blank plasma and plasma obtained at steady state. Unbound clearance of diflunisal exceeded liver plasma flow. Frequency distributions of the elimination of the conjugates of diflunisal were normally distributed. Sex, smoking, and use of vitamins or oral contraceptives were identified as factors which may affect the elimination of

  7. Optimization to eliminate the interference of migration isomers for measuring 1-O-beta-acyl glucuronide without extensive chromatographic separation.

    PubMed

    Xue, Y-J; Akinsanya, J Billy; Raghavan, Nirmala; Zhang, Donglu

    2008-01-01

    A highly selected reaction monitoring (SRM) method has been investigated for the determination of muraglitazar 1-O-beta-acyl glucuronide in animal and human plasma without chromatographic separation of this naturally formed acyl glucuronide from its migration isomers. In the ion source or the collision cell, glucuronides are often prone to lose the dehydrated glucuronic acid (176 Da) and convert back into the parent drug (aglycone). The extent of loss of the glucuronide moiety can differ among glucuronides. For the naturally occurring muraglitazar 1-O-beta-acyl glucuronide, or its synthetic anomer 1-O-alpha-glucuronide, the loss of the glucuronide moiety was a major fragment ion. The loss of the glucuronide moiety was greater for the 1-O-beta-acyl glucuronide than the 1-O-alpha-anomer. In addition, the loss of the glucuronide moiety was insignificant (less than 0.01%) with the other glucuronide isomers (2-, 3- or 4-O, alpha or beta). Given the fact that the 1-O-alpha-anomer was a minor impurity in the muraglitazar 1-O-beta-acyl glucuronide reference standard, and not either a conversion product of 1-O-beta-acyl glucuronide or endogenously formed, the SRM transition corresponding to the loss of the glucuronide moiety was very specific for 1-O-beta-acyl glucuronide, and practically free from interference of the other isomers under optimized collision-cell conditions. As a result, extensive chromatographic separation of 1-O-beta-acyl glucuronide from its migration isomers was not required. The use of this specific SRM transition effectively reduced the separation time from 12.0 min of a long-column high-performance liquid chromatography (HPLC) method to 2.5 min by use of a shorter column. The standard curve performance and analysis results of 1-O-beta-acyl glucuronide incubation samples showed that the short-column method could produce equivalent results to the long-column method but with a 4.5-fold improvement in sample throughput. This approach may be useful for

  8. Human UDP-glucuronosyltransferase (UGT) 2B10 in drug N-glucuronidation: substrate screening and comparison with UGT1A3 and UGT1A4.

    PubMed

    Kato, Yukiko; Izukawa, Takeshi; Oda, Shingo; Fukami, Tatsuki; Finel, Moshe; Yokoi, Tsuyoshi; Nakajima, Miki

    2013-07-01

    Recent observations revealed that human UDP-glucuronosyltransferase (UGT) 2B10 catalyzes N-glucuronidation of amine-containing compounds. Knowledge of the substrate specificity and clinical significance of UGT2B10 is still limited. The purpose of this study was to expand the knowledge of UGT2B10 substrates and to evaluate its significance in drug clearance. Using recombinant UGT2B10, we found that it catalyzes the N-glucuronidation of amitriptyline, imipramine, ketotifen, pizotifen, olanzapine, diphenhydramine, tamoxifen, ketoconazole, and midazolam. These are drugs that were previously reported to be substrates for UGT1A4 or UGT1A3, and that contain in their structure either tertiary aliphatic amines, cyclic amines, or an imidazole group. UGT2B10 was inactive in the glucuronidation of desipramine, nortriptyline, carbamazepine, and afloqualone. This group of drugs contains secondary or primary amines, and these results suggest that UGT2B10 preferably conjugates tertiary amines. This preference is partial because UGT2B10 did not conjugate the tertiary cyclic amine in trifluoperazine. Kinetic analyses revealed that the affinity and clearance of UGT2B10 for amitriptyline, imipramine, and diphenhydramine are significantly higher than the corresponding values of UGT1A4 and UGT1A3, although the Vmax values of UGT1A4 toward these drugs are considerably higher. These findings suggest that UGT2B10 plays a major role in the N-glucuronidation of these drugs at therapeutic concentrations. These results are also supported by inhibition studies with nicotine and hecogenin. In conclusion, this study expands the understanding of the substrate specificity of UGT2B10, highlighting its preference for tertiary amines with higher affinities and clearance values than those of UGT1A4 and UGT1A3.

  9. Differences between human and rat intestinal and hepatic bisphenol A glucuronidation and the influence of alamethicin on in vitro kinetic measurements.

    PubMed

    Mazur, Christopher S; Kenneke, John F; Hess-Wilson, Janet K; Lipscomb, John C

    2010-12-01

    The extent to which membrane-disrupting agents, such as alamethicin, may alter cofactor transport and influence in vitro kinetic measurements of glucuronidation is a major concern regarding the characterization and extrapolation of inter- and intraspecies pharmacokinetics of bisphenol A (BPA). An additional concern is the omission of a BPA intestinal metabolism component in current pharmacokinetic models used to assess oral exposure. In this study, BPA glucuronidation in native hepatic microsomes from female rat and female human liver displayed higher V(max) values than that in males. In the presence of alamethicin, all hepatic V(max) values increased; however, this increase was disproportionately greater in males and gender differences were no longer observed. Female rats exhibited a much higher K(m) than all other species and genders; the addition of alamethicin had little influence on K(m) values for any of the test systems. The dissimilar K(m) measured for female rat suggests that different UDP-glucuronosyltransferase (UGT) enzyme(s) are involved in BPA glucuronidation. The presence of different UGTs in female rat was confirmed using Hill coefficients measured from diclofenac-mediated chemical inhibition assays within hepatic microsomes and purified human UGT2B7 and UGT2B15. Mixed-gender human intestinal microsomes showed little BPA glucuronidation reactivity compared with those from male rat intestine. Male rat intestinal microsomes in the presence of alamethicin exhibited a V(max) that was nearly 30-fold higher than that for mixed human microsomes. The species and gender metabolic differences we observed between rat and human liver and intestine provide key information for delineating BPA pharmacokinetics needed for human health risk assessment.

  10. Acetaminophen-Induced Hepatotoxicity: a Comprehensive Update

    PubMed Central

    Yoon, Eric; Babar, Arooj; Choudhary, Moaz; Kutner, Matthew; Pyrsopoulos, Nikolaos

    2016-01-01

    Abstract Hepatic injury and subsequent hepatic failure due to both intentional and non-intentional overdose of acetaminophen (APAP) has affected patients for decades, and involves the cornerstone metabolic pathways which take place in the microsomes within hepatocytes. APAP hepatotoxicity remains a global issue; in the United States, in particular, it accounts for more than 50% of overdose-related acute liver failure and approximately 20% of the liver transplant cases. The pathophysiology, disease course and management of acute liver failure secondary to APAP toxicity remain to be precisely elucidated, and adverse patient outcomes with increased morbidity and mortality continue to occur. Although APAP hepatotoxicity follows a predictable timeline of hepatic failure, its clinical presentation might vary. N-acetylcysteine (NAC) therapy is considered as the mainstay therapy, but liver transplantation might represent a life-saving procedure for selected patients. Future research focus in this field may benefit from shifting towards obtaining antidotal knowledge at the molecular level, with focus on the underlying molecular signaling pathways. PMID:27350943

  11. Sulforaphane protects against acetaminophen-induced hepatotoxicity.

    PubMed

    Noh, Jung-Ran; Kim, Yong-Hoon; Hwang, Jung Hwan; Choi, Dong-Hee; Kim, Kyoung-Shim; Oh, Won-Keun; Lee, Chul-Ho

    2015-06-01

    Oxidative stress is closely associated with acetaminophen (APAP)-induced toxicity. Heme oxygenase-1 (HO-1), an antioxidant defense enzyme, has been shown to protect against oxidant-induced tissue injury. This study investigated whether sulforaphane (SFN), as a HO-1 inducer, plays a protective role against APAP hepatotoxicity in vitro and in vivo. Pretreatment of primary hepatocyte with SFN induced nuclear factor E2-factor related factor (Nrf2) target gene expression, especially HO-1 mRNA and protein expression, and suppressed APAP-induced glutathione (GSH) depletion and lipid peroxidation, which eventually leads to hepatocyte cell death. A comparable effect was observed in mice treated with APAP. Mice were treated with 300 mg/kg APAP 30 min after SFN (5 mg/kg) administration and were then sacrificed after 6 h. APAP alone caused severe liver injuries as characterized by increased plasma AST and ALT levels, GSH depletion, apoptosis, and 4-hydroxynonenal (4-HNE) formations. This APAP-induced liver damage was significantly attenuated by pretreatment with SFN. Furthermore, while hepatic reactive oxygen species (ROS) levels were increased by APAP exposure, pretreatment with SFN completely blocked ROS formation. These results suggest that SFN plays a protective role against APAP-mediated hepatotoxicity through antioxidant effects mediated by HO-1 induction. SFN has preventive action in oxidative stress-mediated liver injury.

  12. Erdosteine against acetaminophen induced renal toxicity.

    PubMed

    Isik, Bunyamin; Bayrak, Reyhan; Akcay, Ali; Sogut, Sadik

    2006-07-01

    Acetaminophen (APAP) induced toxicities have been a major problem in clinical practice. The aim of the present study was to demonstrate a possible protective role of erdosteine, a mucolytic agent having antioxidant properties via its active metabolites, on APAP induced renal damage in rats. Female Wistar Albino rats were divided into groups including control, erdosteine (150 mg/kg, oral), APAP (1 g/kg, oral) APAP+erdosteine (150 mg/kg, oral) and APAP+erdosteine (300 mg/kg, oral). APAP treatment caused lipid peroxidation as well as high NO level in renal tissue. Also, APAP treated rats had decreased activities of CAT and GSH-Px, but not SOD. In addition, tubular epithelial degeneration, vacuolization and cell desquamation were clearly observed in the APAP treated rats. The cellular debris in the proximal tubules and cortical interstitial congestions were prominent in the kidneys of APAP treated rats. BUN and creatinine levels were increased after APAP administration. All these pathological changes were reversed after erdosteine treatments. Erdosteine treated APAP groups showed milder tubular degeneration, epithelial vacuolization in the proximal tubules, lesser cellular desquamation and better morphology when compared with APAP groups. In conclusion, erdosteine may be a choice of preventive treatment against APAP induced nephrotoxicity.

  13. Molecular Pathways: GLI1-Induced Drug Glucuronidation in Resistant Cancer Cells.

    PubMed

    Zahreddine, Hiba Ahmad; Borden, Katherine L B

    2015-05-15

    Drug resistance remains a major impediment in the development of durable cancer therapies. Studies in acute myelogenous leukemia (AML) patients revealed a new form of multidrug resistance. Here, increased glioma-associated protein GLI1 leads to elevation of the UDP-glucuronosyl transferase (UGT) enzymes. UGTs add glucuronic acid to xenobiotics and metabolites. Traditionally, the loss of these enzymes is thought to contribute to cancer as a result of impaired clearance of environmental carcinogens. However, we demonstrate that overexpression of UGTs can contribute to oncogenesis by promoting drug resistance. Indeed, UGT levels in AML patients treated with ribavirin and/or cytarabine were elevated at relapse relative to diagnosis. This was reversed by GLI1 inhibition, suggesting a clinically relevant strategy to overcome drug resistance. Further, overexpression of UGTs can also lead to drug resistance in other cancers, such as certain Hsp90 inhibitors and vorinostat in colorectal and chronic lymphoblastic leukemia, respectively. Not all drugs are targets of glucuronidation, suggesting that UGT status could be relevant to treatment choice. Here, we describe several facets of UGT biology and how these could be exploited clinically. These studies demonstrate how drugs in cancer cells can be metabolized differentially than their normal counterparts. In summary, we describe a new form of drug resistance relevant to a variety of cancer contexts.

  14. Patient perception and knowledge of acetaminophen in a large family medicine service.

    PubMed

    Herndon, Christopher M; Dankenbring, Dawn M

    2014-06-01

    The use of acetaminophen is currently under increased scrutiny by the US Food and Drug Administration (FDA) due to the risk of intentional and more concerning, unintentional overdose-related hepatotoxicity. Acetaminophen is responsible for an estimated 48% of all acute liver failure diagnoses. The purpose of this study is to evaluate patient perception and knowledge of the safe use and potential toxicity of acetaminophen-containing products. The authors conducted a descriptive, 2-week study using a convenience sample from a large family medicine clinic waiting room. Survey questions assessed ability to identify acetaminophen, knowledge of the current recommended maximum daily dose, respondent acetaminophen use patterns, common adverse effects associated with acetaminophen, and respondent self-reported alcohol consumption. Acetaminophen safety information was provided to all persons regardless of participation in the study. Of the 102 patients who chose to participate, 79% recognized acetaminophen as a synonym of Tylenol, whereas only 9% identified APAP as a frequently used abbreviation. One third of respondents thought acetaminophen was synonymous with ibuprofen and naproxen. Approximately one fourth of patients correctly identified the then maximum recommended daily acetaminophen dose of 4 g. Seventy-eight percent of patients correctly identified hepatotoxicity as the most common serious adverse effect. We conclude that patient deficiencies in knowledge of acetaminophen recognition, dosing, and toxicity warrant public education by health professionals at all levels of interaction. Current initiatives are promising; however, further efforts are required.

  15. Acetaminophen versus Ibuprofen in Young Children with Mild Persistent Asthma

    PubMed Central

    Sheehan, W.J.; Mauger, D.T.; Paul, I.M.; Moy, J.N.; Boehmer, S.J.; Szefler, S.J.; Fitzpatrick, A.M.; Jackson, D.J.; Bacharier, L.B.; Cabana, M.D.; Covar, R.; Holguin, F.; Lemanske, R.F.; Martinez, F.D.; Pongracic, J.A.; Beigelman, A.; Baxi, S.N.; Benson, M.; Blake, K.; Chmiel, J.F.; Daines, C.L.; Daines, M.O.; Gaffin, J.M.; Gentile, D.A.; Gower, W.A.; Israel, E.; Kumar, H.V.; Lang, J.E.; Lazarus, S.C.; Lima, J.J.; Ly, N.; Marbin, J.; Morgan, W.J.; Myers, R.E.; Olin, J.T.; Peters, S.P.; Raissy, H.H.; Robison, R.G.; Ross, K.; Sorkness, C.A.; Thyne, S.M.; Wechsler, M.E.; Phipatanakul, W.

    2016-01-01

    BACKGROUND Studies have suggested an association between frequent acetaminophen use and asthma-related complications among children, leading some physicians to recommend that acetaminophen be avoided in children with asthma; however, appropriately designed trials evaluating this association in children are lacking. METHODS In a multicenter, prospective, randomized, double-blind, parallel-group trial, we enrolled 300 children (age range, 12 to 59 months) with mild persistent asthma and assigned them to receive either acetaminophen or ibuprofen when needed for the alleviation of fever or pain over the course of 48 weeks. The primary outcome was the number of asthma exacerbations that led to treatment with systemic glucocorticoids. Children in both treatment groups received standardized asthma-controller therapies that were used in a simultaneous, factorially linked trial. RESULTS Participants received a median of 5.5 doses (interquartile range, 1.0 to 15.0) of trial medication; there was no significant between-group difference in the median number of doses received (P = 0.47). The number of asthma exacerbations did not differ significantly between the two groups, with a mean of 0.81 per participant with acetaminophen and 0.87 per participant with ibuprofen over 46 weeks of follow-up (relative rate of asthma exacerbations in the acetaminophen group vs. the ibuprofen group, 0.94; 95% confidence interval, 0.69 to 1.28; P = 0.67). In the acetaminophen group, 49% of participants had at least one asthma exacerbation and 21% had at least two, as compared with 47% and 24%, respectively, in the ibuprofen group. Similarly, no significant differences were detected between acetaminophen and ibuprofen with respect to the percentage of asthma-control days (85.8% and 86.8%, respectively; P = 0.50), use of an albuterol rescue inhaler (2.8 and 3.0 inhalations per week, respectively; P = 0.69), unscheduled health care utilization for asthma (0.75 and 0.76 episodes per participant

  16. In vitro glucuronidation of the antibacterial triclocarban and its oxidative metabolites.

    PubMed

    Schebb, N H; Franze, B; Maul, R; Ranganathan, A; Hammock, B D

    2012-01-01

    Triclocarban (3,4,4'-trichlorocarbanilide; TCC) is widely used as an antibacterial in bar soaps. During use of these soaps, a significant portion of TCC is absorbed by humans. For the elimination from the body, glucuronidation plays a key role in both biliary and renal clearance. To investigate this metabolic pathway, we performed microsomal incubations of TCC and its hydroxylated metabolites 2'-OH-TCC, 3'-OH-TCC, and 6-OH-TCC. Using a new liquid chromatography-UV-mass spectrometry method, we could show a rapid glucuronidation for all OH-TCCs by the uridine-5'-diphosphate-glucuronosyltransferases (UGT) present in liver microsomes of humans (HLM), cynomolgus monkeys (CLM), rats (RLM), and mice (MLM). Among the tested human UGT isoforms, UGT1A7, UGT1A8, and UGT1A9 showed the highest activity for the conjugation of hydroxylated TCC metabolites followed by UGT1A1, UGT1A3, and UGT1A10. Due to this broad pattern of active UGTs, OH-TCCs can be efficiently glucuronidated in various tissues, as shown for microsomes from human kidney (HKM) and intestine (HIM). The major renal metabolites in humans, TCC-N-glucuronide and TCC-N'-glucuronide, were formed at very low conversion rates (<1%) by microsomal incubations. Low amounts of N-glucuronides were generated by HLM, HIM, and HKM, as well as by MLM and CLM, but not by RLM, according to the observed species specificity of this metabolic pathway. Among the human UGT isoforms, only UGT1A9 had activity for the N-glucuronidation of TCC. These results present an anomaly where in vivo the predominant urinary metabolites of TCC are N and N'-glucuronides, but these compounds are slowly produced in vitro.

  17. [Carbohydrate deficient transferrin and ethyl glucuronide: markers for alcohol use].

    PubMed

    Paling, Erik P; Mostert, Leendert J

    2013-01-01

    In this article, we report on the usefulness of physicians testing for carbohydrate deficient transferrin (CDT) and ethyl glucuronide (EtG) when there are doubts about alcohol use by their patients. A 44-year-old male consulted his general practitioner with depressive symptoms and denied using alcohol. Laboratory examination revealed an elevated CDT value. The latter was caused by chronic alcohol use. The second patient, a 32-year-old female with known alcohol dependence and receiving inpatient treatment at an addiction clinic, came back from leave. She denied having consumed alcohol and her blood alcohol concentration was zero. Examination of her urine showed an elevated EtG/creatinine ratio. This was caused by having had a few drinks during her leave and could not have been caused by using mouthwash or disinfection soap. We describe how to use the results of CDT and EtG testing in the therapeutic process and give recommendations for patient communication before performing these two tests.

  18. Connexin32: a mediator of acetaminophen-induced liver injury?

    PubMed Central

    Maes, Michaël; McGill, Mitchell R.; da Silva, Tereza Cristina; Lebofsky, Margitta; de Araújo, Cintia Maria Monteiro; Tiburcio, Taynã; Pereira, Isabel Veloso Alves; Willebrords, Joost; Yanguas, Sara Crespo; Farhood, Anwar; Dagli, Maria Lucia Zaidan; Jaeschke, Hartmut; Cogliati, Bruno; Vinken, Mathieu

    2016-01-01

    Connexin32 is the building block of hepatocellular gap junctions, which control direct intercellular communication and thereby act as goalkeepers of liver homeostasis. This study was set up to investigate whether connexin32 is involved in hepatotoxicity induced by the analgesic and antipyretic drug acetaminophen. To this end, whole body connexin32 knock-out mice were overdosed with acetaminophen followed by sampling at different time points within a 24-hour time frame. Evaluation was done based upon a series of clinically and mechanistically relevant read-outs, including protein adduct formation, histopathological examination, measurement of alanine aminotransferase activity, cytokine production, levels of reduced and oxidized glutathione, and hepatic protein amounts of proliferating cell nuclear antigen. In essence, it was found that genetic ablation of connexin32 has no influence on several key events in acetaminophen-induced hepatotoxicity, including cell death, inflammation or oxidative stress, yet it does affect production of protein adducts as well as proliferating cell nuclear antigen steady-state protein levels. This outcome is not in line with previous studies, which are contradicting on their own, as both amplification and alleviation of this toxicological process by connexin32 have been described. This could question the suitability of the currently available models and tools to investigate the role of connexin32 in acetaminophen-triggered hepatotoxicity. PMID:26739117

  19. Connexin32: a mediator of acetaminophen-induced liver injury?

    PubMed

    Maes, Michaël; McGill, Mitchell R; da Silva, Tereza Cristina; Lebofsky, Margitta; Maria Monteiro de Araújo, Cintia; Tiburcio, Taynã; Veloso Alves Pereira, Isabel; Willebrords, Joost; Crespo Yanguas, Sara; Farhood, Anwar; Zaidan Dagli, Maria Lucia; Jaeschke, Hartmut; Cogliati, Bruno; Vinken, Mathieu

    2016-02-01

    Connexin32 is the building block of hepatocellular gap junctions, which control direct intercellular communication and thereby act as goalkeepers of liver homeostasis. This study was set up to investigate whether connexin32 is involved in hepatotoxicity induced by the analgesic and antipyretic drug acetaminophen. To this end, whole body connexin32 knock-out mice were overdosed with acetaminophen followed by sampling at different time points within a 24-h time frame. Evaluation was done based upon a series of clinically and mechanistically relevant read-outs, including protein adduct formation, histopathological examination, measurement of alanine aminotransferase activity, cytokine production, levels of reduced and oxidized glutathione and hepatic protein amounts of proliferating cell nuclear antigen. In essence, it was found that genetic ablation of connexin32 has no influence on several key events in acetaminophen-induced hepatotoxicity, including cell death, inflammation or oxidative stress, yet it does affect production of protein adducts as well as proliferating cell nuclear antigen steady-state protein levels. This outcome is not in line with previous studies, which are contradicting on their own, as both amplification and alleviation of this toxicological process by connexin32 have been described. This could question the suitability of the currently available models and tools to investigate the role of connexin32 in acetaminophen-triggered hepatotoxicity.

  20. Recent Updates on Acetaminophen Hepatotoxicity: The Role of Nrf2 in Hepatoprotection

    PubMed Central

    Gum, Sang Il

    2013-01-01

    Acetaminophen (APAP) known as paracetamol is the main ingredient in Tylenol, which has analgesic and anti-pyretic properties. Inappropriate use of APAP causes major morbidity and mortality secondary to hepatic failure. Overdose of APAP depletes the hepatic glutathione (GSH) rapidly, and the metabolic intermediate leads to hepatocellular death. This article reviews the mechanisms of hepatotoxicity and provides an overview of current research studies. Pharmacokinetics including metabolism (activation and detoxification), subsequent transport (efflux)-facilitating excretion, and some other aspects related to toxicity are discussed. Nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated gene battery plays a critical role in the multiple steps associated with the mitigation of APAP toxicity. The role of Nrf2 as a protective target is described, and potential natural products inhibiting APAP toxicity are outlined. This review provides an update on the mechanism of APAP toxicity and highlights the beneficial role of Nrf2 and specific natural products in hepatoprotection. PMID:24386516

  1. In vitro glucuronidation kinetics of deoxynivalenol by human and animal microsomes and recombinant human UGT enzymes.

    PubMed

    Maul, Ronald; Warth, Benedikt; Schebb, Nils Helge; Krska, Rudolf; Koch, Matthias; Sulyok, Michael

    2015-06-01

    The mycotoxin deoxynivalenol (DON), formed by Fusarium species, is one of the most abundant mycotoxins contaminating food and feed worldwide. Upon ingestion, the majority of the toxin is excreted by humans and animal species as glucuronide conjugate. First in vitro data indicated that DON phase II metabolism is strongly species dependent. However, kinetic data on the in vitro metabolism as well as investigations on the specific enzymes responsible for DON glucuronidation in human are lacking. In the present study, the DON metabolism was investigated using human microsomal fractions and uridine-diphosphoglucuronyltransferases (UGTs) as well as liver microsomes from five animal species. Only two of the twelve tested human recombinant UGTs led to the formation of DON glucuronides with a different regiospecificity. UGT2B4 predominantly catalyzed the formation of DON-15-O-glucuronide (DON-15GlcA), while for UGT2B7 the DON-3-O-glucuronide (DON-3GlcA) metabolite prevailed. For human UGTs, liver, and intestinal microsomes, the glucuronidation activities were low. The estimated apparent intrinsic clearance (Clapp,int) for all human UGT as well as tissue homogenates was <1 mL/min mg protein. For the animal liver microsomes, moderate Clapp,int between 1.5 and 10 mL/min mg protein were calculated for carp, trout, and porcine liver. An elevated glucuronidation activity was detected for rat and bovine liver microsomes leading to Clapp,int between 20 and 80 mL/min mg protein. The obtained in vitro data points out that none of the animal models is suitable for estimating the human DON metabolism with respect to the metabolite pattern and formation rate.

  2. Human hydroxylated metabolites of BDE-47 and BDE-99 are glucuronidated and sulfated in vitro.

    PubMed

    Erratico, Claudio; Zheng, Xiaobo; Ryden, Andreas; Marsh, Goran; Maho, Walid; Covaci, Adrian

    2015-07-16

    Polybrominated diphenyl ethers (PBDEs) were used worldwide as additive flame retardants and are classified as persistent, bioaccumulable and toxic environmental pollutants. In humans, the hydroxylated metabolites of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) formed in vitro have also been detected in vivo. To further characterize the metabolism of BDE-47 and BDE-99 and to identify candidate markers for monitoring the human exposure to PBDEs using non-invasive approaches, glucuronidation and sulfation of hydroxylated metabolites of BDE-47 and BDE-99 were investigated using human liver microsomes and cytoplasm, respectively. The formed Phase II metabolites were analyzed by liquid chromatography-tandem mass spectrometry using a novel approach to develop analytical methods in absence of authentic standards. All available standards for hydroxylated metabolites of BDE-47 and BDE-99 were glucuronidated and sulfated, showing that glucuronidation and sulfation are part of the metabolism pathway of BDE-47 and BDE-99 in vitro. The major glucuronidated and sulfated analogs of hydroxylated metabolites of BDE-47 were (a) 2,4-DBP-Gluc and 5-Gluc-BDE-47, and (b) 2'-Sulf-BDE-28, 4-Sulf-BDE-42 and 3-Sulf-BDE-47, respectively. The major glucuronidated and sulfated analogs of hydroxylated metabolites of BDE-99 were (a) 2,4,5-TBP-Gluc and 6'-Gluc-BDE-99, and (b) 3'-Sulf-BDE-99 and 5'-Sulf-BDE-99, respectively. Apparent Km values associated with the formation of sulfated metabolites of BDE-47 and BDE-99 were ten times lower than those of the corresponding glucuronidated metabolites, suggesting that sulfated rather than glucuronidated metabolites of OH-PBDEs might be used as markers of human exposure to PBDEs using a non-invasive approach based on urine sample collection.

  3. The role of xenobiotic glucuronidating enzymes in drug resistance of tumour tissues and cells.

    PubMed

    Burchell, B; Baird, S; Coughtrie, M W

    1990-01-01

    Xenobiotic and endobiotic glucuronidation is regulated by many cellular features such as (a) access of substrates to a family of microsomal enzymes, the UDP-glucuronosyltransferases (UDPGTs) and (b) mechanisms of transport and excretion of glucuronides from the cell. We have isolated molecular biological probes identifying human UDPGTs to facilitate the examination of mechanisms regulating the functional expression of UDPGTs during natural development, in genetic diseases and in cancer cells. UDPGTs are encoded by a multigene family. Seven rat and four human UDPGT cDNAs have been cloned and expressed in cell culture to determine their substrate specificity and ability to glucuronidate xenobiotics. Analysis of the amino acid sequences of cloned UDPGTs has provided information about their method of synthesis and topological orientation with the lumen of the endoplasmic reticulum (ER). The location of hepatic UDPGT raises interesting questions about the role of possible transporters essential for functional glucuronidation. Measurement of the UDPGT activities and UDPGT mRNA in carcinoma tissue and in hepatic nodules from rats suggest that increases in the level of a phenol-UDPGT may contribute to drug resistance in cancer. Human UDPGTs stably expressed in cell lines have been used to study the glucuronidation of carcinogens and anticancer drugs. Human phenol UDPGT will catalyse the glucuronidation of carcinogens. The high levels of expression of human phenol UDPGT in tissue culture cells could also lead to an increased resistance to xenobiotic toxicity caused by mitoxantrone, mitomycin C, and adriamycin. This molecular cell biology approach is being used to further assess the glucuronidation and effective toxicity of anticancer drugs.

  4. Identification of a novel N-carbamoyl glucuronide: in vitro, in vivo, and mechanistic studies.

    PubMed

    Gunduz, Mithat; Argikar, Upendra A; Baeschlin, Daniel; Ferreira, Suzie; Hosagrahara, Vinayak; Harriman, Shawn

    2010-03-01

    1-[4-Aminomethyl-4-(3-chlorophenyl)-cyclohexyl]-tetrahydro-pyrimidin- 2-one, 1, was developed as an inhibitor of dipeptidyl peptidase-4 enzyme. Biotransformation studies with 1 revealed the presence of an N-carbamoyl glucuronide metabolite (M1) in rat bile and urine. N-Carbamoyl glucuronides are rarely observed, and little is understood regarding the mechanism of N-carbamoyl glucuronidation. The objectives of the current investigation were to elucidate the structure of the novel N-carbamoyl glucuronide, to investigate the mechanism of N-carbamoyl glucuronide formation in vitro using stable labeled CO(2), UDP glucuronosyltransferase (UGT) reaction phenotyping, and to assess whether M1 was formed to the same extent in vitro across species-mouse, rat, hamster, dog, monkey, and human. Structure elucidation was performed on a mass spectrometer with accurate mass measurement and MS(n) capabilities. (13)C-labeled carbon dioxide was used for identification of the mechanism of N-carbamoyl glucuronidation. Mechanistic studies with (13)C-labeled CO(2) in rat liver microsomes revealed that CO(2) from the bicarbonate buffer (in equilibrium with exogenous CO(2)) may be responsible for the formation of M1. M1 was formed in vitro in liver microsomes from multiple species, mainly rat and hamster, followed by similar formation in dog, monkey, mouse, and human. M1 could be detected in UGT1A1, UGT1A3, and UGT2B7 Supersomes in a CO(2)-rich environment. In conclusion, our study demonstrates that formation of M1 was observed in microsomal incubations across various species and strongly suggests incorporation of CO(2) from the bicarbonate buffer, in equilibrium with exogenous CO(2), into the carbamoyl moiety of the formed N-carbamoyl glucuronide.

  5. Efficacy of Intravenous Infusion of Acetaminophen for Intrapartum Analgesia

    PubMed Central

    Zutshi, Vijay; Rani, Kumari Usha; Patel, Madhumita

    2016-01-01

    Introduction The intensity of pain experienced by women in labour, has been found to affect the progress of labour, foetal well-being and maternal psychology. Adverse effects associated with commonly used opioids for providing intrapartum analgesia have created a need for an alternative non-opioid drug. Aim To evaluate the efficacy of an intravenous infusion of 1000 mg of acetaminophen as an intrapartum analgesic. Materials and Methods The present prospective single-centre, single blind, placebo-controlled randomized interventional study was conducted in Department of Obstetrics and Gynaecology in Vardhaman Mahavir Medical College & Safdarjung Hospital over a period of six months from September 2014 to March 2015. After receiving the ethical clearance and written informed consent. The first 200 consecutive parturients fulfilling the inclusion criteria were recruited into the study. Women were then randomised to receive either intravenous 1000 mg (100ml) of acetaminophen (Group A, n=100) or 100 ml normal saline (Group B, n=100). Primary outcome assessed was effectiveness of acetaminophen to provide an adequate amount of analgesia, as measured by a change in Visual Analogue Scale (VAS) pain intensity score at various times after drug administration. Secondary outcomes measured were duration of labour, need for additional rescue analgesia and presence of adverse maternal or foetal effect. Results There was pain reduction at 1 and 2 hours in both groups (p<0.001). However, it was more significant in the acetaminophen group, especially at 1 hour. Duration of labour was shortened in both the groups, without any maternal and foetal adverse effects. Conclusion Intravenous acetaminophen is an efficacious non-opioid drug for relieving labour pain without any significant maternal and foetal adverse effects. PMID:27656511

  6. Direct radioimmunoassay of urinary estrogen and pregnanediol glucuronides during the menstrual cycle

    SciTech Connect

    Stanczyk, F.Z.; Miyakawa, I.; Goebelsmann, U.

    1980-06-15

    Assays measuring immunoreactive estrone glucuronide (E/sub 1/G), estradiol-3-glucuronide (E/sub 2/-3G), estradiol-17..beta..-glucuronide (E/sub 2/-17G), estriol-3-glucuronide (E/sub 3/-3G), estriol-16..cap alpha..-glucuronide (E/sub 3/-16G), and pregnanediol-3..cap alpha..-glucuronide (Pd-3G) directly in diluted urine were developed and validated. These estrogen and pregnanediol glucuronide fractions were measured in aliquots of 24-hour and overnight samples of urine collected daily from seven women for one menstrual cycle. Urinary hormone excretion was correlated with daily serum estradiol (E/sub 2/), progesterone (P), and lutenizing hormonee (LH) levels. A sharp midcycle LH peak preceded by a preovulatory rise in serum E/sub 2/ and followed by luteal phase serum P levels were noted in each of the seven apparently ovulatory cycles. Twenty-four-hour and overnight urinary excretion patterns of estrogen glucuronides were similar to those of serum E/sub 2/. Of the five estrogen glucuronide fractions tested, excretion of E/sub 2/-17G exhibited the earliest and steepest ascending slope of the preovulatory estrogen surge and correlated best with serum E/sub 2/ levels. Urinary excretion of E/sub 1/-G, E/sub 2/-3G, and E/sub 3/-16G also showed an early and steep preovulatory rise and preceded that of E/sub 3/-3G, whereas urinary excretion of E/sub 3/-3G exhibited the poorest correlation with serum E/sub 2/ concentrations. The urinary excretion of Pd-3G rose parallel to serum P levels and was markedly elevated 2 to 3 days after the midcycle LH peak in both 24-hour and overnight collections of urine. These results indicate that among the urinary estrogen conjugate fractions tested, E/sub 2/-17G is the one that most suitably predicts ovulation.

  7. Adaptation to acetaminophen exposure elicits major changes in expression and distribution of the hepatic proteome.

    PubMed

    Eakins, R; Walsh, J; Randle, L; Jenkins, R E; Schuppe-Koistinen, I; Rowe, C; Starkey Lewis, P; Vasieva, O; Prats, N; Brillant, N; Auli, M; Bayliss, M; Webb, S; Rees, J A; Kitteringham, N R; Goldring, C E; Park, B K

    2015-11-26

    Acetaminophen overdose is the leading cause of acute liver failure. One dose of 10-15 g causes severe liver damage in humans, whereas repeated exposure to acetaminophen in humans and animal models results in autoprotection. Insight of this process is limited to select proteins implicated in acetaminophen toxicity and cellular defence. Here we investigate hepatic adaptation to acetaminophen toxicity from a whole proteome perspective, using quantitative mass spectrometry. In a rat model, we show the response to acetaminophen involves the expression of 30% of all proteins detected in the liver. Genetic ablation of a master regulator of cellular defence, NFE2L2, has little effect, suggesting redundancy in the regulation of adaptation. We show that adaptation to acetaminophen has a spatial component, involving a shift in regionalisation of CYP2E1, which may prevent toxicity thresholds being reached. These data reveal unexpected complexity and dynamic behaviour in the biological response to drug-induced liver injury.

  8. Adaptation to acetaminophen exposure elicits major changes in expression and distribution of the hepatic proteome

    PubMed Central

    Eakins, R.; Walsh, J.; Randle, L.; Jenkins, R. E.; Schuppe-Koistinen, I.; Rowe, C.; Starkey Lewis, P.; Vasieva, O.; Prats, N.; Brillant, N.; Auli, M.; Bayliss, M.; Webb, S.; Rees, J. A.; Kitteringham, N. R.; Goldring, C. E.; Park, B. K.

    2015-01-01

    Acetaminophen overdose is the leading cause of acute liver failure. One dose of 10–15 g causes severe liver damage in humans, whereas repeated exposure to acetaminophen in humans and animal models results in autoprotection. Insight of this process is limited to select proteins implicated in acetaminophen toxicity and cellular defence. Here we investigate hepatic adaptation to acetaminophen toxicity from a whole proteome perspective, using quantitative mass spectrometry. In a rat model, we show the response to acetaminophen involves the expression of 30% of all proteins detected in the liver. Genetic ablation of a master regulator of cellular defence, NFE2L2, has little effect, suggesting redundancy in the regulation of adaptation. We show that adaptation to acetaminophen has a spatial component, involving a shift in regionalisation of CYP2E1, which may prevent toxicity thresholds being reached. These data reveal unexpected complexity and dynamic behaviour in the biological response to drug-induced liver injury. PMID:26607827

  9. Isoliquiritigenin showed strong inhibitory effects towards multiple UDP-glucuronosyltransferase (UGT) isoform-catalyzed 4-methylumbelliferone (4-MU) glucuronidation.

    PubMed

    Lu, Hang; Fang, Zhong-Ze; Cao, Yun-Feng; Hu, Cui-Min; Hong, Mo; Sun, Xiao-Yu; Li, Hua; Liu, Yan; Fu, Xiaoguang; Sun, Hongzhi

    2013-01-01

    Isoliquiritigenin, a herbal ingredient with chalcone structure, has been speculated to be able to inhibit one of the most drug-metabolizing enzymes (DMEs) UDP-glucuronosyltransferase (UGT). Therefore, the aim of the present study was to investigate the inhibition of isoliquiritigenin towards important UGT isoforms in the liver and intestine, including UGT1A1, 1A3, 1A6, 1A7, 1A8, 1A9 and 1A10. The recombinant UGT-catalyzed 4-methylumbelliferone (4-MU) glucuronidation was used as probe reactions. The results showed that 100μM of isoliquiritigenin inhibited the activity of UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A9, and UGT1A10 by 95.2%, 76.1%, 78.9%, 87.2%, 67.2%, 94.8%, and 91.7%, respectively. The data fitting using Dixon plot and Lineweaver-Burk plot showed that the inhibition of UGT1A1, UGT1A9 and UGT1A10 by isoliquiritigenin was all best fit to the competitive inhibition, and the second plot using the slopes from the Lineweaver-Burk plot versus isoliquiritigenin concentrations was used to calculate the inhibition kinetic parameter (K(i)) to be 0.7μM, 0.3μM, and 18.3μM for UGT1A1, UGT1A9, and UGT1A10, respectively. All these results indicated the risk of clinical application of isoliquiritigenin on the drug-drug interaction and other possible diseases induced by the inhibition of isoliquiritigenin towards these UGT isoforms.

  10. Separation and Purification of Two Flavone Glucuronides from Erigeron multiradiatus (Lindl.) Benth with Macroporous Resins

    PubMed Central

    Zhang, Zhi-feng; Liu, Yuan; Luo, Pei; Zhang, Hao

    2009-01-01

    Scutellarein-7-O-β-D-glucuronide (SG) and apigenin-7-O-β-D-glucuronide (AG) are two major bioactive constituents with known pharmacological effects in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141, and D160 have been evaluated. The results confirmed that D141 resin offered the best adsorption and desorption capacities and the highest desorption ratio for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin under optimal ethanol conditions and fitted well to the Freundlich and Langmuir models (R2 > 0.95). Dynamic adsorption and desorption tests was performed on column packed with D141 resin. After one-run treatment with D141 resin, the two-constituent content in the final product was increased from 2.14% and 1.34% in the crude extract of Erigeron multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The preparative separation of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method developed can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials. PMID:19918373

  11. Desorption chemical ionization and fast atom bombardment mass spectrometric studies of the glucuronide metabolites of doxylamine.

    PubMed

    Lay, J O; Korfmacher, W A; Miller, D W; Siitonen, P; Holder, C L; Gosnell, A B

    1986-11-01

    Three glucuronide metabolites of doxylamine succinate were collected in a single fraction using high-performance liquid chromatography (HPLC) from the urine of dosed male Fischer 344 rats. The metabolites were then separated using an additional HPLC step into fractions containing predominantly a single glucuronide metabolite. Analysis of the metabolites by methane and ammonia desorption chemical ionization, with and without derivatization, revealed fragment ions suggestive of a hydroxylated doxylamine moiety. Identification of the metabolites as glucuronides of doxylamine, desmethyldoxylamine and didesmethyldoxylamine was accomplished, based on determination of the molecular weight and exact mass of each metabolite using fast atom bombardment (FAB) ionization. This assignment was confirmed by the fragmentation observed in FAB mass spectrometric and tandem mass spectrometric experiments. Para-substitution of the glucuronide on the phenyl moiety was observed by 500-MHz nuclear magnetic resonance (NMR) spectrometry. A fraction containing all three glucuronide metabolites, after a single stage of HPLC separation, was also analysed by FAB mass spectrometry, and the proton- and potassium-containing quasimolecular ions for all three metabolites were observed.

  12. Isolation, purification, and structural characterization of flunixin glucuronide in the urine of greyhound dogs.

    PubMed

    Brady, T C; Kind, A J; Hyde, W H; Favrow, M; Hill, D W

    1998-04-01

    A urinary metabolite of flunixin in greyhound dogs was isolated and purified by a gradient-elution solid-phase extraction technique. The purified metabolite was shown to be hydrolyzed to free flunixin by strong base and by beta-glucuronidase, suggesting the presence of a C1-beta-glucuronide ester of flunixin. The metabolite was further characterized by positive-ion, tandem MS with electrospray ionization. Mass spectral data showed the presence of a protonated molecular ion (M+1) at m/z 473, which was consistent with the molecular weight of protonated flunixin glucuronide, and a product ion at m/z 297, which was consistent with the molecular weight of protonated flunixin. Collisionally induced dissociation of the m/z 297 product ion showed a fragmentation pattern consistent with that of standard flunixin. These data support the contention that this metabolite of flunixin in greyhound urine is the C1-beta-glucuronide of flunixin. Acyl glucuronide metabolites of some organic acid drugs have been shown to bind covalently to tissue proteins in vitro, in vivo, and ex vivo. The presence of this metabolite may, therefore, have pharmacokinetic and pharmacodynamic implications for flunixin in greyhound dogs, as well as in other animal species in which the acyl glucuronide of flunixin is a metabolite.

  13. New Flavonol Glucuronides from the Flower Buds of Syzygium aromaticum (Clove).

    PubMed

    Ryu, Byeol; Kim, Hye Mi; Lee, Jin Su; Lee, Chan Kyu; Sezirahiga, Jurdas; Woo, Jeong-Hwa; Choi, Jung-Hye; Jang, Dae Sik

    2016-04-20

    Repeated chromatography of the EtOAc-soluble fraction from the 70% EtOH extract of the flower buds of Syzygium aromaticum (clove) led to the isolation and characterization of four new flavonol glucuronides, rhamnetin-3-O-β-d-glucuronide (1), rhamnazin-3-O-β-d-glucuronide (2), rhamnazin-3-O-β-d-glucuronide-6″-methyl ester (3), and rhamnocitrin-3-O-β-d-glucuronide-6″-methyl ester (4), together with 15 flavonoids (5-19) having previously known chemical structures. The structures of the new compounds 1-4 were determined by interpretation of spectroscopic data, particularly by 1D- and 2D-NMR studies. Six flavonoids (6, 7, 9, 14, 18, and 19) were isolated from the flower buds of S. aromaticum for the first time in this study. The flavonoids were examined for their cytotoxicity against human ovarian cancer cells (A2780) using MTT assays. Among the isolates, pachypodol (19) showed the most potent cytotoxicity on A2780 cells with an IC50 value of 8.02 μM.

  14. The cynomolgus monkey (Macaca fascicularis) is the best animal model for the study of steroid glucuronidation.

    PubMed

    Barbier, Olivier; Bélanger, Alain

    2003-06-01

    Intense research efforts performed during the past decade clearly established the major role of glucuronidation and uridine-diphospho-glucuronosyltransferase (UGT) enzymes for steroid metabolism in humans. However, a clear understanding of the physiological importance of this metabolic process requires in vivo studies. Numerous evidences ascertain that simians are the most appropriate animal models for such studies. Indeed human and monkey have a similar pattern of steroidogenesis, unlike common laboratory mammals such as rat or mouse. Furthermore, human and monkey are unique in having high levels of circulating androsterone glucuronide and androstane-3alpha-diol glucuronide (3alpha-Diol-G). In addition, characterization of eight monkey UGT proteins demonstrated the similarity of their conjugation activity toward steroid hormones. Like human ones, monkey enzymes are expressed in steroid target tissues, where they preferentially glucuronidate androgen and estrogen metabolites. In monkey tissues, immunohistochemical studies demonstrated that UGT2B proteins are expressed in a cell-type specific manner in ovary and kidney, where they control androgens and aldosterone inactivation. These results identify the cynomolgus monkey as an appropriate animal model for the determination of cellular localization of UGT enzymes in steroid target tissues and for the identification of endogenous or exogenous stimuli affecting steroid glucuronidation.

  15. A long-standing mystery solved: the formation of 3-hydroxydesloratadine is catalyzed by CYP2C8 but prior glucuronidation of desloratadine by UDP-glucuronosyltransferase 2B10 is an obligatory requirement.

    PubMed

    Kazmi, Faraz; Barbara, Joanna E; Yerino, Phyllis; Parkinson, Andrew

    2015-04-01

    Desloratadine (Clarinex), the major active metabolite of loratadine (Claritin), is a nonsedating long-lasting antihistamine that is widely used for the treatment of allergic rhinitis and chronic idiopathic urticaria. For over 20 years, it has remained a mystery as to which enzymes are responsible for the formation of 3-hydroxydesloratadine, the major active human metabolite, largely due to the inability of any in vitro system tested thus far to generate this metabolite. In this study, we demonstrated that cryopreserved human hepatocytes (CHHs) form 3-hydroxydesloratadine and its corresponding O-glucuronide. CHHs catalyzed the formation of 3-hydroxydesloratadine with a Km of 1.6 μM and a Vmax of 1.3 pmol/min per million cells. Chemical inhibition of cytochrome P450 (P450) enzymes in CHHs demonstrated that gemfibrozil glucuronide (CYP2C8 inhibitor) and 1-aminobenzotriazole (general P450 inhibitor) inhibited 3-hydroxydesloratadine formation by 91% and 98%, respectively. Other inhibitors of CYP2C8 (gemfibrozil, montelukast, clopidogrel glucuronide, repaglinide, and cerivastatin) also caused extensive inhibition of 3-hydroxydesloratadine formation (73%-100%). Assessment of desloratadine, amodiaquine, and paclitaxel metabolism by a panel of individual CHHs demonstrated that CYP2C8 marker activity robustly correlated with 3-hydroxydesloratadine formation (r(2) of 0.70-0.90). Detailed mechanistic studies with sonicated or saponin-treated CHHs, human liver microsomes, and S9 fractions showed that both NADPH and UDP-glucuronic acid are required for 3-hydroxydesloratadine formation, and studies with recombinant UDP-glucuronosyltransferase (UGT) and P450 enzymes implicated the specific involvement of UGT2B10 in addition to CYP2C8. Overall, our results demonstrate for the first time that desloratadine glucuronidation by UGT2B10 followed by CYP2C8 oxidation and a deconjugation event are responsible for the formation of 3-hydroxydesloratadine.

  16. Investigation of the hepatic glucuronidation pattern of the Fusarium mycotoxin deoxynivalenol in various species.

    PubMed

    Maul, Ronald; Warth, Benedikt; Kant, Jill-Sandra; Schebb, Nils Helge; Krska, Rudolf; Koch, Matthias; Sulyok, Michael

    2012-12-17

    Deoxynivalenol (DON) is one of the most abundant mycotoxins contaminating food and feed worldwide. Upon absorption, the major portion of the toxin is excreted by humans and animal species as glucuronide. However, consistent in vitro data on DON glucuronidation are lacking. In the present study, the metabolism of DON was investigated using liver microsomes from humans and six different animal species. It was shown that all animal and human liver microsomes led to the formation of up to three different mono-O-glucuronides with significant interspecies differences. While the activity of human liver microsomes was low (0.8 to 2.2 pmol·min(-1)·mg(-1)), bovine liver and rat liver microsomes conjugated DON with activities of 525 pmol·min(-1)·mg(-1) and 80 pmol·min(-1)·mg(-1), respectively.

  17. Determination of salbutamol and salbutamol glucuronide in human urine by means of liquid chromatography-tandem mass spectrometry.

    PubMed

    Mareck, Ute; Guddat, Sven; Schwenke, Anne; Beuck, Simon; Geyer, Hans; Flenker, Ulrich; Elers, Jimmi; Backer, Vibeke; Thevis, Mario; Schänzer, Wilhelm

    2011-01-01

    The determination of salbutamol and its glucuronide in human urine following the inhalative and oral administration of therapeutic doses of salbutamol preparations was performed by means of direct urine injection utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) and employing d(3)-salbutamol and d(3)-salbutamol glucuronide as internal standards. Unconjugated salbutamol was detected in all administration study urine samples. Salbutamol concentrations following inhalation were commonly (99%) below 1000 ng/ml whereas values after oral administration frequently (48%) exceeded this threshold. While salbutamol glucuronide was not detected in urine samples collected after inhalation of the drug, 26 out of 82 specimens obtained after oral application contained salbutamol glucuronide with a peak value of 63 ng/ml. The percentage of salbutamol glucuronide compared to unconjugated salbutamol was less than 3%. Authentic doping control urine samples indicating screening results for salbutamol less than 1000 ng/ml, showed salbutamol glucuronide concentrations between 2 and 6 ng/ml, whereas adverse analytical findings resulting from salbutamol levels higher than 1000 ng/ml, had salbutamol glucuronide values between 8 and 15 ng/ml. The approach enabled the rapid determination of salbutamol and its glucuronic acid conjugate in human urine and represents an alternative to existing procedures since time-consuming hydrolysis or derivatization steps were omitted. Moreover, the excretion of salbutamol glucuronide in human urine following the administration of salbutamol was proven.

  18. A novel method for the determination of the site of glucuronidation by ion mobility spectrometry-mass spectrometry.

    PubMed

    Shimizu, Atsushi; Ohe, Tomoyuki; Chiba, Masato

    2012-08-01

    Glucuronidation not only plays a detoxifying role in living body, but it also can complicate pharmacological and toxicological profiles of new drug candidates by forming active and reactive conjugated metabolites. The opportunity to elucidate structure of conjugated metabolites has increased in drug metabolism studies at the early development stage. General methodologies for the structure elucidation of glucuronide conjugate(s) include liquid chromatography-tandem mass spectrometry (LC-MS/MS) and NMR spectroscopy. In many cases, LC-MS/MS alone cannot unequivocally identify the site(s) of conjugation in isomeric glucuronidations. In the present study, we established a new strategy for the structure elucidation of glucuronide conjugates using ion mobility spectrometry (IMS)-mass spectrometry. Linear correlation between calculated collision cross-sections (CCS) and actual drift times from IMS was found for each set of parent compound (raloxifene, losartan, telmisartan, and estradiol) and the corresponding MS/MS product ions. Thus, obtained regression lines accurately and selectively projected the actual drift times of authentic standards of glucuronide conjugate based on the theoretical CCS values. The established method was used for the accurate assignment of predominant formation of phenolic glucuronide conjugate (SCH 60663) in the isomeric (phenolic and benzylic) glucuronidations of ezetimibe in the incubated sample with cryopreserved human hepatocytes. This application demonstrates the potential to facilitate the structure identification of glucuronide conjugates at the early development stage of new drug candidates.

  19. Structure-Dependent Deconjugation of Flavonoid Glucuronides by Human β-Glucuronidase - In Vitro and In Silico Analyses.

    PubMed

    Untergehrer, Monika; Bücherl, Daniel; Wittmann, Hans-Joachim; Strasser, Andrea; Heilmann, Jörg; Jürgenliemk, Guido

    2015-08-01

    Flavonoid glycosides are extensively metabolized to glucuronidated compounds after oral intake. Recently, a cleavage of quercetin glucuronides by β-glucuronidase has been found. To characterize the deglucuronidation reaction and its structural prerequisites among the flavonoid subtypes more precisely, four flavonol glucuronides with varying glucuronidation positions, five flavone 7-O-glucuronides with varying A- and B-ring substitution as well as one flavanone- and one isoflavone-7-O-glucuronide were analyzed in a human monocytic cell line. Investigation of the deglucuronidation rates by HPLC revealed a significant influence of the glucuronidation position on enzyme activity for flavonols. Across the flavonoid subtypes, the C-ring saturation also showed a significant influence on deglucuronidation, whereas A- and B-ring variations within the flavone-7-O-glucuronides did not affect the enzymes' activity. Results were compared to computational binding studies on human β-glucuronidase. Additionally, molecular modeling and dynamic studies were performed to obtain detailed insight into the binding and cleavage mode of the substrate at the active site of the human β-glucuronidase.

  20. In vitro characterization of glucuronidation of vanillin: identification of human UDP-glucuronosyltransferases and species differences.

    PubMed

    Yu, Jian; Han, Jing-Chun; Hua, Li-Min; Gao, Ya-Jie

    2013-09-01

    Vanillin is a food flavoring agent widely utilized in foods, beverages, drugs, and perfumes and has been demonstrated to exhibit multiple pharmacological activities. Given the importance of glucuronidation in the metabolism of vanillin, the UDP-glucuronosyltransferase conjugation pathway of vanillin was investigated in this study. Vanillin glucuronide was identified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and a hydrolysis reaction catalyzed by β-glucuronidase. The kinetic study showed that vanillin glucuronidation by HLMs and HIMs followed Michaelis-Menten kinetics and the kinetic parameters were as follows: 134.9 ± 13.5 μM and 81.3 ± 11.3 μM for K(m) of HLMs and HIMs, 63.8 ± 2.0 nmol/min/mg pro and 13.4 ±2.0 nmol/min/mg pro for Vmax of HLMs and HIMs. All UDP-glucuronosyltransferase (UGT) isoforms except UGT1A4, 1A9, and 2B7 showed the capability to glucuronidate vanillin, and UGT1A6 exerted the higher V(max)/K(m) values than other UGT isoforms for the glucuronidation of vanillin when assuming expression of isoforms is similar in recombinant UGTs. Kinetic analysis using liver microsomes from six studied speices indicated that vanillin had highest affinity for the monkey liver microsomes enzyme (K(m)  = 25.6 ± 3.2 μM) and the lowest affinity for the mice liver microsomes enzyme (K(m)  = 149.1 ± 18.4 μM), and intrinsic clearance was in the following order: monkey > dog > minipig > mice > rat ~ human. These data collectively provided important information for understanding glucuronidation of vanillin.

  1. Glucuronidation versus oxidation of the flavonoid galangin by human liver microsomes and hepatocytes.

    PubMed

    Otake, Yoko; Hsieh, Faye; Walle, Thomas

    2002-05-01

    In a previous study, we used human liver microsomes for the first time to study cytochrome P450 (P450)-mediated oxidation of the flavonoid galangin. The combination of CYP1A2 and CYP2C9 produced a V(max)/K(m) value of 13.6 +/- 1.1 microl/min/mg of protein. In the present extended study, we determined glucuronidation rates for galangin with the same microsomes. Two major and one minor glucuronide were identified by liquid chromatography/mass spectrometry. The V(max)/K(m) values for the two major glucuronides conjugated in the 7- and 3-positions were 155 +/- 30 and 427 +/- 26 microl/min/mg of protein, thus, exceeding that of oxidation by 11 and 31 times, respectively. This highly efficient glucuronidation appeared to be catalyzed mainly by the UDP-glucuronosyltransferase (UGT)1A9 isoform but also by UGT1A1 and UGT2B15. Sulfation of galangin by the human liver cytosol, mediated mainly but not exclusively by sulfotransferase (SULT) 1A1, also appeared to be efficient. These conclusions were strongly supported by experiments using the S9 fraction of the human liver, in which all three metabolic pathways could be directly compared. When galangin metabolism was examined in fresh plated hepatocytes from six donors, glucuronidation clearly predominated followed by sulfation. Oxidation occurred only to a minor extent in two of the donors. This study for the first time establishes that glucuronidation and sulfation of galangin, and maybe other flavonoids, are more efficient than P450-mediated oxidation, clearly being the metabolic pathways of choice in intact cells and therefore likely also in vivo.

  2. Co-administration of N-Acetylcysteine and Acetaminophen Efficiently Blocks Acetaminophen Toxicity.

    PubMed

    Owumi, Solomon E; Andrus, James P; Herzenberg, Leonard A; Herzenberg, Leonore A

    2015-08-01

    Preclinical Research Although acetaminophen (APAP) is an effective analgesic and anti-pyretic, APAP overdose is the most frequent cause of serious, often lethal, drug-induced hepatotoxicity. Administration of N-acetyl cysteine (NAC) within 8 hours of APAP overdose effectively mitigates APAP-induced hepatotoxicity. Thus, preventing APAP toxicity before it occurs by formulating APAP with NAC is logical and, as we show here in a mouse model, is effective in preventing APAP toxicity. Thus, toxic oral APAP doses sufficient to cause severe widespread liver damage do not cause significant damage when administered concurrently with equal amounts of NAC, that is, in the NAC-APAP treated animals, hepatic transaminases increase only marginally and liver architecture remains fully intact. Thus, we conclude that concomitant oral dosing with APAP and NAC can provide a convenient and effective way of preventing toxicity associated with large dosage of APAP. From a public health perspective, these findings support the concept that a co-formulation of APAP plus NAC is a viable over-the-counter (OTC) alternative to the current practice of providing APAP OTC and treating APAP toxicity if/when it occurs. In essence, our findings indicate that replacing the current OTC APAP with a safe and functional APAP/NAC formulation could prevent the accidental and intentional APAP toxicity that occurs today.

  3. Role of nicotinamide (vitamin B3) in acetaminophen-induced changes in rat liver: Nicotinamide effect in acetaminophen-damged liver.

    PubMed

    Mahmoud, Yomna I; Mahmoud, Asmaa A

    2016-06-01

    Acetaminophen is a widely used analgesic and antipyretic agent, which is safe at therapeutic doses. However, overdoses of acetaminophen induce severe oxidative stress, which leads to acute liver failure. Nicotinamide has proven effective in ameliorating many pathological conditions that occur due to oxidative stress. This study verifies the prophylactic and therapeutic effects of nicotinamide against the hepatic pathophysiological and ultrastructural alterations induced by acetaminophen. Wistar rats intoxicated with an acute overdose of acetaminophen (5g/kg b.wt) were given a single dose of nicotinamide (500mg/kg b.wt) either before or after intoxication. Acetaminophen caused significant elevation in the liver functions and lipid peroxidation marker, and decline in the activities of the hepatic antioxidant enzymes. This oxidative injury was associated with hepatic centrilobular necrosis, hemorrage, vacuolar degeneration, lipid accumulation and mitochondrial alterations. Treating intoxicated rats with nicotinamide (500mg/kg) significantly ameliorated acetaminophen-induced biochemical changes and pathological injuries. However, administering the same dose of nicotinamide to healthy animals or prior to acetaminophen-intoxication induced hepatotoxicity. Caution should be taken when administering high doses of NAM because of its possible hepatotoxicity. Considering the wide use of nicotinamide, there is an important need for monitoring nicotinamide tolerance, safety and efficacy in healthy and diseased subjects.

  4. Toxic epidermal necrolysis caused by acetaminophen featuring almost 100% skin detachment: Acetaminophen is associated with a risk of severe cutaneous adverse reactions.

    PubMed

    Watanabe, Hideaki; Kamiyama, Taisuke; Sasaki, Shun; Kobayashi, Kae; Fukuda, Kenichiro; Miyake, Yasufumi; Aruga, Tohru; Sueki, Hirohiko

    2016-03-01

    Toxic epidermal necrolysis (TEN) is an adverse reaction that can be induced by various drugs; the associated mortality rate is 20-25%. A previous report showed a weak association between TEN and acetaminophen. Recently, the US Food and Drug Administration declared that acetaminophen is associated with a risk of serious skin reactions, including TEN. Here, we describe the case of a 43-year-old Japanese woman with TEN caused by acetaminophen. She had poorly controlled ulcerative colitis and was treated with high doses of prednisolone, infliximab, acetaminophen and lansoprazole. Nine days after administrating acetaminophen, targetoid erythematous and bullous lesions appeared on the patient's trunk, palms and the soles of her feet. The skin lesions expanded rapidly; within 3 weeks, skin detachment was detected across nearly 100% of the patient's body. However, no mucosal involvement of the eyes, oral cavity or genitalia was found. We performed lymphocyte transformation tests using various drugs; however, a high stimulation index was obtained only with acetaminophen. The patient recovered following treatment with plasmapheresis, i.v. immunoglobulin therapy, topical medication and supportive therapy. Acetaminophen is included in many prescription and over-the-counter products; thus, clinicians should monitor their patients for severe drug reactions, including TEN.

  5. Acetaminophen effects on behavioral thermoregulation in albino rats.

    PubMed

    Vitulli, W F; Kaiser, G A; Maranto, D L; Blake, S E; Storey, T M; McPherson, K P; Luper, S L

    1999-02-01

    Acetaminophen (N-Acetyl-p-aminophenol) was administered intraperitoneally to 15 Sprague-Dawley rats partitioned into 3 studies (5 rats per study) using a within subjects, repeated-measures reversal design. Behavioral thermoregulation was assessed in a cold Skinner Box using 5-sec. exposures of microwave radiation [Specific Absorption Rate = 0.34 Watts/kg/(mW/cm2)] as reinforcing stimuli under a fixed-interval 2-min. schedule of positive reinforcement. Doses of 10, 20, 30, 40, and 50 mg/kg (in solutions of 1%, 2%, 3%, 4%, and 5%) acetaminophen showed stable rates of operant responding for heat compared with significant changes in rates for comparable doses of aspirin in a 1993 study by Vitulli, et al. Weight reductions and temperature increases varied significantly with before-session and after-session measures, respectively. 1994-95 biochemical data of Murphy, et al. from humans following aspirin or acetaminophen ingestion which affect thermoregulation and sleep patterns are discussed in conjunction with behavioral data from rats.

  6. Acute acetaminophen overdose is associated with dose-dependent hypokalaemia: a prospective study of 331 patients.

    PubMed

    Waring, W Stephen; Stephen, Alexandra F L; Malkowska, Aleks M; Robinson, Oliver D G

    2008-03-01

    Hypokalaemia is a recognized complication of acute acetaminophen overdose. It is unclear whether this might be a pharmacological effect of acetaminophen, or due to association with confounding factors. The present study sought to better characterize the relationship between acetaminophen concentrations and risk of hypokalaemia. A prospective study of patients received N-acetylcysteine treatment within 15 hr of acute acetaminophen ingestion. Serum potassium concentrations were determined before and after N-acetylcysteine. Serum acetaminophen concentrations were used to indicate overall drug exposure by comparison to the Rumack-Matthew nomogram. Hypokalaemia was pre-defined by serum concentrations <3.5 mmol/l, and groups compared by Mann-Whitney tests. There were 331 patients. Median (95% confidence interval) fall in serum potassium concentration after N-acetylcysteine was 0.05 mmol/l (-0.11-0.30 mmol/l) if acetaminophen concentrations were below the 'high-risk' treatment line, 0.30 mmol/l (0.17-0.40 mmol/l) if between the 'high-risk' and 'normal' treatment lines (P = 0.0358), and 0.40 mmol/l (0.20-0.50 mmol/l) if above the 'normal' treatment line (P = 0.0136). A receiver operating characteristic showed that high acetaminophen concentrations were predictive of hypokalaemia (P = 0.0001 versus zero discriminatory line), and 4 hr acetaminophen concentration >156 mmol/l gave 81% sensitivity and 48% specificity. The risk of hypokalaemia after acute acetaminophen overdose depends on the extent of acetaminophen exposure, irrespective of N-acetylcysteine administration and independent of whether vomiting occurred. Acetaminophen appears to cause concentration-dependent hypokalaemia after overdose, and the pharmacological basis requires further consideration.

  7. Comparative evaluation of the pain-relieving properties of a lecithinized formulation of curcumin (Meriva(®)), nimesulide, and acetaminophen.

    PubMed

    Di Pierro, Francesco; Rapacioli, Giuliana; Di Maio, Eleonora Adriana; Appendino, Giovanni; Franceschi, Federico; Togni, Stefano

    2013-01-01

    In addition to its anti-inflammatory activity, Meriva(®), a proprietary lecithin formulation of curcumin, has been anecdotally reported to decrease acute pain in patients with various chronic diseases. Given that curcumin can desensitize transient receptor potential A1, a nociceptor seemingly also mediating the analgesic effect of acetaminophen, as well as inhibiting and downregulating the expression of cyclo-oxygenase 2, the selective target of nimesulide, a nonsteroidal anti-inflammatory agent, we carried out a pilot comparative study of the acute pain-relieving properties of these three agents. At a dose of 2 g (corresponding to 400 mg of curcumin), Meriva showed clear analgesic activity, comparable with that of a standard dose (1 g) of acetaminophen, but lower than that of a therapeutic (100 mg) dose of nimesulide. The analgesic activity of lower (1.5 g) doses of Meriva was less satisfactory, and the onset of activity was longer than that of nimesulide for both doses. On the other hand, gastric tolerability was significantly better than that of nimesulide and comparable with that of acetaminophen. Taken together, our results show that the preclinical analgesic properties of curcumin have clinical relevance, at least at a dose of 2 g as the Meriva formulation. While this dose is significantly higher than that used to relieve chronic inflammatory conditions (1-1.2 g/day), its pain-relieving activity could benefit from the general downregulation of the inflammatory response induced by curcumin, considering that the transient receptor potential channel-mediated mechanisms of analgesia are magnified by attenuation of inflammation. In patients on treatment with Meriva, this would also translate into better control of acute pain, providing a rationale for the analgesic properties associated with this curcumin formulation.

  8. The neuronal nitric oxide synthase inhibitor NANT blocks acetaminophen toxicity and protein nitration in freshly isolated hepatocytes.

    PubMed

    Banerjee, Sudip; Melnyk, Stepan B; Krager, Kimberly J; Aykin-Burns, Nukhet; Letzig, Lynda G; James, Laura P; Hinson, Jack A

    2015-12-01

    3-Nitrotyrosine (3NT) in liver proteins of mice treated with hepatotoxic doses of acetaminophen (APAP) has been postulated to be causative in toxicity. Nitration is by a reactive nitrogen species formed from nitric oxide (NO). The source of the NO is unclear. iNOS knockout mice were previously found to be equally susceptible to APAP toxicity as wildtype mice and iNOS inhibitors did not decrease toxicity in mice or in hepatocytes. In this work we examined the potential role of nNOS in APAP toxicity in hepatocytes using the specific nNOS inhibitor NANT (10 µM)(N-[(4S)-4-amino-5-[(2-aminoethyl)amino]pentyl]-N'-nitroguanidinetris (trifluoroacetate)). Primary hepatocytes (1 million/ml) from male B6C3F1 mice were incubated with APAP (1mM). Cells were removed and assayed spectrofluorometrically for reactive nitrogen and oxygen species using diaminofluorescein (DAF) and Mitosox red, respectively. Cytotoxicity was determined by LDH release into media. Glutathione (GSH, GSSG), 3NT, GSNO, acetaminophen-cysteine adducts, NAD, and NADH were measured by HPLC. APAP significantly increased cytotoxicity at 1.5-3.0 h. The increase was blocked by NANT. NANT did not alter APAP mediated GSH depletion or acetaminophen-cysteine adducts in proteins which indicated that NANT did not inhibit metabolism. APAP significantly increased spectroflurometric evidence of reactive nitrogen and oxygen formation at 0.5 and 1.0 h, respectively, and increased 3NT and GSNO at 1.5-3.0 h. These increases were blocked by NANT. APAP dramatically increased NADH from 0.5-3.0 h and this increase was blocked by NANT. Also, APAP decreased the Oxygen Consumption Rate (OCR), decreased ATP production, and caused a loss of mitochondrial membrane potential, which were all blocked by NANT.

  9. Contribution of acetaminophen-cysteine to acetaminophen nephrotoxicity II. Possible involvement of the gamma-glutamyl cycle.

    PubMed

    Stern, Stephan T; Bruno, Mary K; Horton, Robert A; Hill, Dennis W; Roberts, Jeanette C; Cohen, Steven D

    2005-01-15

    Acetaminophen (APAP) nephrotoxicity has been observed both in humans and research animals. Our recent investigations have focused on the possible involvement of glutathione-derived APAP metabolites in APAP nephrotoxicity and have demonstrated that administration of acetaminophen-cysteine (APAP-CYS) potentiated APAP-induced renal injury with no effects on APAP-induced liver injury. Additionally, APAP-CYS treatment alone resulted in a dose-responsive renal GSH depletion. This APAP-CYS-induced renal GSH depletion could interfere with intrarenal detoxification of APAP or its toxic metabolite N-acetyl-p-benzoquinoneimine (NAPQI) and may be the mechanism responsible for the potentiation of APAP nephrotoxicity. Renal-specific GSH depletion has been demonstrated in mice and rats following administration of amino acid gamma-glutamyl acceptor substrates for gamma-glutamyl transpeptidase (gamma-GT). The present study sought to determine if APAP-CYS-induced renal glutathione depletion is the result of disruption of the gamma-glutamyl cycle through interaction with gamma-GT. The results confirmed that APAP-CYS-induced renal GSH depletion was antagonized by the gamma-glutamyl transpeptidase (gamma-GT) inhibitor acivicin. In vitro analysis demonstrated that APAP-CYS is a gamma-glutamyl acceptor for both murine and bovine renal gamma-GT. Analysis of urine from mice pretreated with acivicin and then treated with APAP, APAP-CYS, or acetaminophen-glutathione identified a gamma-glutamyl-cysteinyl-acetaminophen metabolite. These findings are consistent with the hypothesis that APAP-CYS contributes to APAP nephrotoxicity by depletion of renal GSH stores through interaction with the gamma-glutamyl cycle.

  10. Immunoblot analysis of protein containing 3-(cystein-S-yl)acetaminophen adducts in serum and subcellular liver fractions from acetaminophen-treated mice.

    PubMed

    Pumford, N R; Hinson, J A; Benson, R W; Roberts, D W

    1990-07-01

    The hepatotoxicity of acetaminophen is believed to be mediated by the metabolic activation of acetaminophen to N-acetyl-p-benzoquinone imine which covalently binds to cysteinyl residues on proteins as 3-(cystein-S-yl)acetaminophen adducts. The formation of these adducts in hepatic protein correlates with the hepatotoxicity. In this study, the formation of 3-(cystein-S-yl)acetaminophen adducts in specific cellular proteins was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and detected using affinity-purified antisera specific for 3-(cystein-S-yl)acetaminophen adducts on immunoblots. These techniques were used to investigate the liver 10,000g supernatant and serum from B6C3F1 mice that received hepatotoxic doses of acetaminophen. More than 15 proteins containing 3-(cystein-S-yl)acetaminophen adducts were detected in the liver 10,000g supernatant. The most prominent protein containing 3-(cystein-S-yl)acetaminophen adducts in the hepatic 10,000g supernatant had a relative molecular mass of 55 kDa. Serum proteins containing 3-(cystein-S-yl)acetaminophen adducts had molecular masses similar to those found in the liver 10,000g supernatant (55, 87, and approximately 102 kDa). These data, combined with our previous findings describing the temporal relationship between the appearance of 3-(cystein-S-yl)acetaminophen adducts in protein in the serum and the decrease in the levels of 3-(cystein-S-yl)acetaminophen adducts in protein in the liver, suggested that liver adducts were released into the serum following lysis of hepatocytes. The temporal relationship between the formation of specific adducts and hepatotoxicity in mice following a hepatotoxic dose of acetaminophen was examined using immunoblots of mitochondria, microsomes, cytosol, and plasma membranes. Hepatotoxicity indicated by serum alanine aminotransferase levels was increased at 2 and 4 hr after dosing. The cytosolic fraction contained numerous proteins with 3-(cystein-S-yl)acetaminophen

  11. Sulphation of acetaminophen by the human cytosolic sulfotransferases: a systematic analysis.

    PubMed

    Yamamoto, Akihiro; Liu, Ming-Yih; Kurogi, Katsuhisa; Sakakibara, Yoichi; Saeki, Yuichi; Suiko, Masahito; Liu, Ming-Cheh

    2015-12-01

    Sulphation is known to be critically involved in the metabolism of acetaminophen in vivo. This study aimed to systematically identify the major human cytosolic sulfotransferase (SULT) enzyme(s) responsible for the sulphation of acetaminophen. A systematic analysis showed that three of the twelve human SULTs, SULT1A1, SULT1A3 and SULT1C4, displayed the strongest sulphating activity towards acetaminophen. The pH dependence of the sulphation of acetaminophen by each of these three SULTs was examined. Kinetic parameters of these three SULTs in catalysing acetaminophen sulphation were determined. Moreover, sulphation of acetaminophen was shown to occur in HepG2 human hepatoma cells and Caco-2 human intestinal epithelial cells under the metabolic setting. Of the four human organ samples tested, liver and intestine cytosols displayed considerably higher acetaminophen-sulphating activity than those of lung and kidney. Collectively, these results provided useful information concerning the biochemical basis underlying the metabolism of acetaminophen in vivo previously reported.

  12. Hepatoprotective effects of rice-derived peptides against acetaminophen-induced damage in mice

    PubMed Central

    Kawakami, Kayoko; Moritani, Chie; Uraji, Misugi; Fujita, Akiko; Kawakami, Koji; Hatanaka, Tadashi; Suzaki, Etsuko; Tsuboi, Seiji

    2017-01-01

    Glutathione, the most abundant intracellular antioxidant, protects cells against reactive oxygen species induced oxidative stress and regulates intracellular redox status. We found that rice peptides increased intracellular glutathione levels in human hepatoblastoma HepG2 cells. Acetaminophen is a commonly used analgesic. However, an overdose of acetaminophen causes severe hepatotoxicity via depletion of hepatic glutathione. Here, we investigated the protective effects of rice peptides on acetaminophen-induced hepatotoxicity in mice. ICR mice were orally administered rice peptides (0, 100 or 500 mg/kg) for seven days, followed by the induction of hepatotoxicity via intraperitoneal injection of acetaminophen (700 mg/kg). Pretreatment with rice peptides significantly prevented increases in serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase levels and protected against hepatic glutathione depletion. The expression of γ-glutamylcysteine synthetase, a key regulatory enzyme in the synthesis of glutathione, was decreased by treatment with acetaminophen, albeit rice peptides treatment recovered its expression compared to that achieved treatment with acetaminophen. In addition, histopathological evaluation of the livers also revealed that rice peptides prevented acetaminophen-induced centrilobular necrosis. These results suggest that rice peptides increased intracellular glutathione levels and could protect against acetaminophen-induced hepatotoxicity in mice.

  13. Glucuronidation of OTS167 in Humans Is Catalyzed by UDP-Glucuronosyltransferases UGT1A1, UGT1A3, UGT1A8, and UGT1A10

    PubMed Central

    Ramírez, Jacqueline; Mirkov, Snezana; House, Larry K.

    2015-01-01

    OTS167 is a potent maternal embryonic leucine zipper kinase inhibitor undergoing clinical testing as antineoplastic agent. We aimed to identify the UDP-glucuronosyltransferases (UGTs) involved in OTS167 metabolism, study the relationship between UGT genetic polymorphisms and hepatic OTS167 glucuronidation, and investigate the inhibitory potential of OTS167 on UGTs. Formation of a single OTS167-glucuronide (OTS167-G) was observed in pooled human liver (HLM) (Km = 3.4 ± 0.2 µM), intestinal microsomes (HIM) (Km = 1.7 ± 0.1 µM), and UGTs. UGT1A1 (64 µl/min/mg) and UGT1A8 (72 µl/min/mg) exhibited the highest intrinsic clearances (CLint) for OTS167, followed by UGT1A3 (51 µl/min/mg) and UGT1A10 (47 µl/min/mg); UGT1A9 was a minor contributor. OTS167 glucuronidation in HLM was highly correlated with thyroxine glucuronidation (r = 0.91, P < 0.0001), SN-38 glucuronidation (r = 0.79, P < 0.0001), and UGT1A1 mRNA (r = 0.72, P < 0.0001). Nilotinib (UGT1A1 inhibitor) and emodin (UGT1A8 and UGT1A10 inhibitor) exhibited the highest inhibitory effects on OTS167-G formation in HLM (68%) and HIM (47%). We hypothesize that OTS167-G is an N-glucuronide according to mass spectrometry. A significant association was found between rs6706232 and reduced OTS167-G formation (P = 0.03). No or weak UGT inhibition (range: 0–21%) was observed using clinically relevant OTS167 concentrations (0.4–2 µM). We conclude that UGT1A1 and UGT1A3 are the main UGTs responsible for hepatic formation of OTS167-G. Intestinal UGT1A1, UGT1A8, and UGT1A10 may contribute to first-pass OTS167 metabolism after oral administration. PMID:25870101

  14. Age-related increases in F344 rat intestine microsomal quercetin glucuronidation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to establish the extent age modifies intestinal quercetin glucuronidation capacity. Pooled microsomal fractions of three equidistant small intestine (SI) segments from 4, 12, 18, and 28 mo male F344 rats (n=8/group) were employed to model the enzyme kinetics of UDP-gl...

  15. DEVELOPMENT OF A CLASS-SELECTIVE ENZYME IMMUNOASSAY FOR URINARY PHENOLIC GLUCURONIDES. (R825433)

    EPA Science Inventory

    Class-selective immunoassays for the measurement of glucuronides in human urine can aid evaluation of human exposure to complex mixtures of xenobiotics. Therefore, an enzyme immunoassay (EIA) for the group-selective detection of phenolic Profiling serum bile acid glucuronides in humans: gender divergences, genetic determinants and response to fenofibrate

    PubMed Central

    Trottier, Jocelyn; Perreault, Martin; Rudkowska, Iwona; Levy, Cynthia; Dallaire-Theroux, Amélie; Verreault, Mélanie; Caron, Patrick; Staels, Bart; Vohl, Marie-Claude; Straka, Robert J.; Barbier, Olivier

    2014-01-01

    Glucuronidation, catalyzed by UDP-glucuronosyltransferase (UGT) enzymes detoxifies cholestatic bile acids (BAs). We aimed at i) characterizing the circulating BA-glucuronide (-G) pool composition in humans, ii) evaluating how sex and UGT polymorphisms influence this composition, and iii) analyzing the effects of lipid-lowering drug fenofibrate on the circulating BA-G profile in 300 volunteers and 5 cholestatic patients. Eleven BA-Gs were determined in pre- and post-fenofibrate samples. Men exhibited higher BA-G concentrations, and various genotype/BA-G associations were discovered in relevant UGT genes. The chenodeoxycholic acid-3G concentration was associated with the UGT2B7 802C>T polymorphism. Glucuronidation assays confirmed the predominant role of UGT2B7 and UGT1A4 in CDCA-3G formation. Fenofibrate exposure increased the serum levels of 5 BA-G species, including CDCA-3G, and up-regulated expression of UGT1A4, but not UGT2B7, in hepatic cells. This study demonstrates that fenofibrate stimulates BA glucuronidation in humans, and thus reduces bile acid toxicity in the liver. PMID:23756370

  16. Profiling serum bile acid glucuronides in humans: gender divergences, genetic determinants, and response to fenofibrate.

    PubMed

    Trottier, J; Perreault, M; Rudkowska, I; Levy, C; Dallaire-Theroux, A; Verreault, M; Caron, P; Staels, B; Vohl, M-C; Straka, R J; Barbier, O

    2013-10-01

    Glucuronidation, catalyzed by uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes, detoxifies cholestatic bile acids (BAs). We aimed to (i) characterize the circulating BA-glucuronide (BA-G) pool composition in humans, (ii) determine how sex and UGT polymorphisms influence this composition, and (iii) analyze the effects of the lipid-lowering drug fenofibrate on the circulating BA-G profile in 300 volunteers and 5 cholestatic patients. Eleven BA-Gs were determined in pre- and postfenofibrate samples. Men exhibited higher BA-G concentrations, and various genotype/BA-G associations were discovered in relevant UGT genes. The chenodeoxycholic acid-3G (CDCA-3G) concentration was associated with the UGT2B7 802C>T polymorphism. Glucuronidation assays confirmed the predominant role of UGT2B7 and UGT1A4 in CDCA-3G formation. Fenofibrate exposure increased the serum levels of five BA-G species, including CDCA-3G, and upregulated expression of UGT1A4, but not UGT2B7, in hepatic cells. This study demonstrated that fenofibrate stimulates BA glucuronidation in humans and thus reduces BA toxicity in the liver.

  17. Voucher-Based Reinforcement for Alcohol Abstinence Using the Ethyl-Glucuronide Alcohol Biomarker

    ERIC Educational Resources Information Center

    McDonell, Michael G.; Howell, Donelle N,; McPherson, Sterling; Cameron, Jennifer M.; Srebnik, Debra; Roll, John M.; Ries, Richard K.

    2012-01-01

    This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase.…

  18. Effect of succinic acid and tween-80 on glucuronidation of 2-ethyl-6-methyl-3-hydroxypyridine.

    PubMed

    Baranov, P A; Kravtsova, O U; Sariev, A K; Sherdev, V P

    2008-07-01

    We studied the effect of succinic acid on the process of glucuronidation of 2-ethyl-6-methyl-3-hydroxypyridine after peroral and intraperitoneal administration in the form of succinate or a base. Since the basic form of 2-ethyl-6-methyl-3-hydroxypyridine is insoluble in water, it was administered in 5% Tween-80. It was necessary to evaluate also the effect of Tween-80 on glucuronidation of 2-ethyl-6-methyl-3-hydroxypyridine in different administration routes. Quantitative assay of glucuronidated fractions was performed by the method of reversed-phase HPLC with fluorometrical detection. The detection limit for this method was 10 ng/ml. We confirmed that the major excretion pathway for 2-ethyl-6-methyl-3-hydroxypyridine is conjugation with glucuronic acid. It was found that succinic acid increased excretion of glucuronidated metabolite after both peroral and intraperitoneal administration of 2-ethyl-6-methyl-3-hydroxypyridine in the form of succinate and base in 5% Tween-80. The effect of Tween-80 was detected only after peroral administration, which was probably related to its effect on absorption of this compound. Tween-80 increased excretion of glucuronate after peroral administration of 2-ethyl-6-methyl-3-hydroxypyridine in the form of succinate and in 5% Tween solution.

  19. 'Omics analysis of low dose acetaminophen intake demonstrates novel response pathways in humans

    SciTech Connect

    Jetten, Marlon J.A.; Gaj, Stan; Ruiz-Aracama, Ainhoa; Kok, Theo M. de; Delft, Joost H.M. van; Lommen, Arjen; Someren, Eugene P. van; Jennen, Danyel G.J.; Claessen, Sandra M.; Peijnenburg, Ad A.C.M.; Stierum, Rob H.; Kleinjans, Jos C.S.

    2012-03-15

    Acetaminophen is the primary cause of acute liver toxicity in Europe/USA, which led the FDA to reconsider recommendations concerning safe acetaminophen dosage/use. Unfortunately, the current tests for liver toxicity are no ideal predictive markers for liver injury, i.e. they only measure acetaminophen exposure after profound liver toxicity has already occurred. Furthermore, these tests do not provide mechanistic information. Here, 'omics techniques (global analysis of metabolomic/gene-expression responses) may provide additional insight. To better understand acetaminophen-induced responses at low doses, we evaluated the effects of (sub-)therapeutic acetaminophen doses on metabolite formation and global gene-expression changes (including, for the first time, full-genome human miRNA expression changes) in blood/urine samples from healthy human volunteers. Many known and several new acetaminophen-metabolites were detected, in particular in relation to hepatotoxicity-linked, oxidative metabolism of acetaminophen. Transcriptomic changes indicated immune-modulating effects (2 g dose) and oxidative stress responses (4 g dose). For the first time, effects of acetaminophen on full-genome human miRNA expression have been considered and confirmed the findings on mRNA level. 'Omics techniques outperformed clinical chemistry tests and revealed novel response pathways to acetaminophen in humans. Although no definitive conclusion about potential immunotoxic effects of acetaminophen can be drawn from this study, there are clear indications that the immune system is triggered even after intake of low doses of acetaminophen. Also, oxidative stress-related gene responses, similar to those seen after high dose acetaminophen exposure, suggest the occurrence of possible pre-toxic effects of therapeutic acetaminophen doses. Possibly, these effects are related to dose-dependent increases in levels of hepatotoxicity-related metabolites. -- Highlights: ► 'Omics techniques outperformed

  1. Acetaminophen self-administered in the drinking water increases the pain threshold of rats (Rattus norvegicus).

    PubMed

    Mickley, G Andrew; Hoxha, Zana; Biada, Jaclyn M; Kenmuir, Cynthia L; Bacik, Stephanie E

    2006-09-01

    Previous studies have suggested that the addition of flavored acetaminophen suspension (for example, Children's Tylenol) in the drinking water of rats may not be effective in producing postoperative analgesia because of low levels of consumption. However, these investigations neither measured analgesia nor compared the consumption by rats that had undergone surgery with that by unmanipulated rats. The present study reports that although unmanipulated rats naive to the taste of flavored acetaminophen do indeed drink significantly less of this liquid than tap water, they drank sufficient amounts of the acetaminophen-containing solution to significantly raise pain thresholds, as measured by the hot-plate test. Moreover, rats that had undergone surgery drank significantly more acetaminophen solution than did those that had no surgery. These data suggest that oral self-administration of flavored acetaminophen by rats may be an appropriate means to reduce pain.

  2. Dietary Dihydromethysticin Increases Glucuronidation of 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanol in A/J Mice, Potentially Enhancing Its Detoxification

    PubMed Central

    Narayanapillai, Sreekanth C.; von Weymarn, Linda B.; Carmella, Steven G.; Leitzman, Pablo; Paladino, Jordan; Upadhyaya, Pramod; Hecht, Stephen S.; Murphy, Sharon E.

    2016-01-01

    Effective chemopreventive agents are needed against lung cancer, the leading cause of cancer death. Results from our previous work showed that dietary dihydromethysticin (DHM) effectively blocked initiation of lung tumorigenesis by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mice, and it preferentially reduced 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)-derived DNA adducts in lung. This study explored the mechanism(s) responsible for DHM’s differential effects on NNK/NNAL-derived DNA damage by quantifying their metabolites in A/J mice. The results showed that dietary DHM had no effect on NNK or NNAL abundance in vivo, indicating that DHM does not affect NNAL formation from NNK. DHM had a minimal effect on cytochrome P450 2A5 (CYP2A5, which catalyzes NNK and NNAL bioactivation in A/J mouse lung), suggesting that it does not inhibit NNAL bioactivation. Dietary DHM significantly increased O-glucuronidated NNAL (NNAL-O-gluc) in A/J mice. Lung and liver microsomes from dietary DHM-treated mice showed enhanced activities for NNAL O-glucuronidation. These results overall support the notion that dietary DHM treatment increases NNAL detoxification, potentially accounting for its chemopreventive efficacy against NNK-induced lung tumorigenesis in A/J mice. The ratio of urinary NNAL-O-gluc and free NNAL may serve as a biomarker to facilitate the clinical evaluation of DHM-based lung cancer chemopreventive agents. PMID:26744252

  3. Dietary Dihydromethysticin Increases Glucuronidation of 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanol in A/J Mice, Potentially Enhancing Its Detoxification.

    PubMed

    Narayanapillai, Sreekanth C; von Weymarn, Linda B; Carmella, Steven G; Leitzman, Pablo; Paladino, Jordan; Upadhyaya, Pramod; Hecht, Stephen S; Murphy, Sharon E; Xing, Chengguo

    2016-03-01

    Effective chemopreventive agents are needed against lung cancer, the leading cause of cancer death. Results from our previous work showed that dietary dihydromethysticin (DHM) effectively blocked initiation of lung tumorigenesis by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mice, and it preferentially reduced 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)-derived DNA adducts in lung. This study explored the mechanism(s) responsible for DHM's differential effects on NNK/NNAL-derived DNA damage by quantifying their metabolites in A/J mice. The results showed that dietary DHM had no effect on NNK or NNAL abundance in vivo, indicating that DHM does not affect NNAL formation from NNK. DHM had a minimal effect on cytochrome P450 2A5 (CYP2A5, which catalyzes NNK and NNAL bioactivation in A/J mouse lung), suggesting that it does not inhibit NNAL bioactivation. Dietary DHM significantly increased O-glucuronidated NNAL (NNAL-O-gluc) in A/J mice. Lung and liver microsomes from dietary DHM-treated mice showed enhanced activities for NNAL O-glucuronidation. These results overall support the notion that dietary DHM treatment increases NNAL detoxification, potentially accounting for its chemopreventive efficacy against NNK-induced lung tumorigenesis in A/J mice. The ratio of urinary NNAL-O-gluc and free NNAL may serve as a biomarker to facilitate the clinical evaluation of DHM-based lung cancer chemopreventive agents.

  4. Role of glucuronidation for hepatic detoxification and urinary elimination of toxic bile acids during biliary obstruction.

    PubMed

    Perreault, Martin; Białek, Andrzej; Trottier, Jocelyn; Verreault, Mélanie; Caron, Patrick; Milkiewicz, Piotr; Barbier, Olivier

    2013-01-01

    Biliary obstruction, a severe cholestatic condition, results in a huge accumulation of toxic bile acids (BA) in the liver. Glucuronidation, a conjugation reaction, is thought to protect the liver by both reducing hepatic BA toxicity and increasing their urinary elimination. The present study evaluates the contribution of each process in the overall BA detoxification by glucuronidation. Glucuronide (G), glycine, taurine conjugates, and unconjugated BAs were quantified in pre- and post-biliary stenting urine samples from 12 patients with biliary obstruction, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The same LC-MS/MS procedure was used to quantify intra- and extracellular BA-G in Hepatoma HepG2 cells. Bile acid-induced toxicity in HepG2 cells was evaluated using MTS reduction, caspase-3 and flow cytometry assays. When compared to post-treatment samples, pre-stenting urines were enriched in glucuronide-, taurine- and glycine-conjugated BAs. Biliary stenting increased the relative BA-G abundance in the urinary BA pool, and reduced the proportion of taurine- and glycine-conjugates. Lithocholic, deoxycholic and chenodeoxycholic acids were the most cytotoxic and pro-apoptotic/necrotic BAs for HepG2 cells. Other species, such as the cholic, hyocholic and hyodeoxycholic acids were nontoxic. All BA-G assayed were less toxic and displayed lower pro-apoptotic/necrotic effects than their unconjugated precursors, even if they were able to penetrate into HepG2 cells. Under severe cholestatic conditions, urinary excretion favors the elimination of amidated BAs, while glucuronidation allows the conversion of cytotoxic BAs into nontoxic derivatives.

  5. Role of Glucuronidation for Hepatic Detoxification and Urinary Elimination of Toxic Bile Acids during Biliary Obstruction

    PubMed Central

    Perreault, Martin; Białek, Andrzej; Trottier, Jocelyn; Verreault, Mélanie; Caron, Patrick; Milkiewicz, Piotr; Barbier, Olivier

    2013-01-01

    Biliary obstruction, a severe cholestatic condition, results in a huge accumulation of toxic bile acids (BA) in the liver. Glucuronidation, a conjugation reaction, is thought to protect the liver by both reducing hepatic BA toxicity and increasing their urinary elimination. The present study evaluates the contribution of each process in the overall BA detoxification by glucuronidation. Glucuronide (G), glycine, taurine conjugates, and unconjugated BAs were quantified in pre- and post-biliary stenting urine samples from 12 patients with biliary obstruction, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The same LC-MS/MS procedure was used to quantify intra- and extracellular BA-G in Hepatoma HepG2 cells. Bile acid-induced toxicity in HepG2 cells was evaluated using MTS reduction, caspase-3 and flow cytometry assays. When compared to post-treatment samples, pre-stenting urines were enriched in glucuronide-, taurine- and glycine-conjugated BAs. Biliary stenting increased the relative BA-G abundance in the urinary BA pool, and reduced the proportion of taurine- and glycine-conjugates. Lithocholic, deoxycholic and chenodeoxycholic acids were the most cytotoxic and pro-apoptotic/necrotic BAs for HepG2 cells. Other species, such as the cholic, hyocholic and hyodeoxycholic acids were nontoxic. All BA-G assayed were less toxic and displayed lower pro-apoptotic/necrotic effects than their unconjugated precursors, even if they were able to penetrate into HepG2 cells. Under severe cholestatic conditions, urinary excretion favors the elimination of amidated BAs, while glucuronidation allows the conversion of cytotoxic BAs into nontoxic derivatives. PMID:24244729

  6. Acetaminophen hepatotoxicity in mice: Effect of age, frailty and exposure type.

    PubMed

    Kane, Alice E; Mitchell, Sarah J; Mach, John; Huizer-Pajkos, Aniko; McKenzie, Catriona; Jones, Brett; Cogger, Victoria; Le Couteur, David G; de Cabo, Rafael; Hilmer, Sarah N

    2016-01-01

    Acetaminophen is a commonly used analgesic that can cause severe hepatotoxicity in overdose. Despite old age and frailty being associated with extensive and long-term utilization of acetaminophen and a high prevalence of adverse drug reactions, there is limited information on the risks of toxicity from acetaminophen in old age and frailty. This study aimed to assess changes in the risk and mechanisms of hepatotoxicity from acute, chronic and sub-acute acetaminophen exposure with old age and frailty in mice. Young and old male C57BL/6 mice were exposed to either acute (300 mg/kg via oral gavage), chronic (100 mg/kg/day in diet for six weeks) or sub-acute (250 mg/kg, t.i.d., for three days) acetaminophen, or saline control. Pre-dosing mice were scored for the mouse clinical frailty index, and after dosing serum and liver tissue were collected for assessment of toxicity and mechanisms. There were no differences with old age or frailty in the degree of hepatotoxicity induced by acute, chronic or subacute acetaminophen exposure as assessed by serum liver enzymes and histology. Age-related changes in the acetaminophen toxicity pathways included increased liver GSH concentrations, increased NQO1 activity and an increased pro- and anti-inflammatory response to acetaminophen in old age. Frailty-related changes included a negative correlation between frailty index and serum protein, albumin and ALP concentrations for some mouse groups. In conclusion, although there were changes in some pathways that would be expected to influence susceptibility to acetaminophen toxicity, there was no overall increase in acetaminophen hepatotoxicity with old age or frailty in mice.

  7. Candidate gene polymorphisms in patients with acetaminophen-induced acute liver failure.

    PubMed

    Court, Michael H; Peter, Inga; Hazarika, Suwagmani; Vasiadi, Magdalini; Greenblatt, David J; Lee, William M

    2014-01-01

    Acetaminophen is a leading cause of acute liver failure (ALF). Genetic differences might predispose some individuals to develop ALF. In this exploratory study, we evaluated genotype frequency differences among patients enrolled by the ALF Study Group who had developed ALF either intentionally from a single-time-point overdose of acetaminophen (n = 78), unintentionally after chronic high doses of acetaminophen (n = 79), or from causes other than acetaminophen (n = 103). The polymorphisms evaluated included those in genes encoding putative acetaminophen-metabolizing enzymes (UGT1A1, UGT1A6, UGT1A9, UGT2B15, SULT1A1, CYP2E1, and CYP3A5) as well as CD44 and BHMT1. Individuals carrying the CYP3A5 rs776746 A allele were overrepresented among ALF patients who had intentionally overdosed with acetaminophen, with an odds ratio of 2.3 (95% confidence interval, 1.1-4.9; P = 0.034) compared with all other ALF patients. This finding is consistent with the enhanced bioactivation of acetaminophen by the CYP3A5 enzyme. Persons homozygous for the CD44 rs1467558 A allele were also overrepresented among patients who had unintentionally developed ALF from chronic acetaminophen use, with an odds ratio of 4.0 (1.0-17.2, P = 0.045) compared with all other ALF subjects. This finding confirms a prior study that found elevated serum liver enzyme levels in healthy volunteers with the CD44 rs1467558 AA genotype who had consumed high doses of acetaminophen for up to 2 weeks. However, both genetic associations were considered relatively weak, and they were not statistically significant after adjustment for multiple comparisons testing. Nevertheless, both CYP3A5 rs776746 and CD44 rs1467558 warrant further investigation as potential genomic markers of enhanced risk of acetaminophen-induced ALF.

  8. Toxicity from repeated doses of acetaminophen in children: assessment of causality and dose in reported cases.

    PubMed

    Heard, Kennon; Bui, Alison; Mlynarchek, Sara L; Green, Jody L; Bond, G Randall; Clark, Richard F; Kozer, Eran; Koff, Raymond S; Dart, Richard C

    2014-01-01

    Liver injury has been reported in children treated with repeated doses of acetaminophen. The objective of this study was to identify and validate reports of liver injury or death in children younger than 6 years who were administered repeated therapeutic doses of acetaminophen. We reviewed US Poison Center data, peer-reviewed literature, US Food and Drug Administration Adverse Event Reports, and US Manufacturer Safety Reports describing adverse effects after acetaminophen administration. Reports that described hepatic abnormalities (description of liver injury or abnormal laboratory testing) or death after acetaminophen administration to children younger than 6 years were included. The identified reports were double abstracted and then reviewed by an expert panel to determine if the hepatic injury was related to acetaminophen and whether the dose of acetaminophen was therapeutic (≤75 mg/kg) or supratherapeutic. Our search yielded 2531 reports of adverse events associated with acetaminophen use. From these cases, we identified 76 cases of hepatic injury and 26 deaths associated with repeated acetaminophen administration. There were 6 cases of hepatic abnormalities and no deaths associated with what our panel determined to be therapeutic doses. A large proportion of cases could not be fully evaluated due to incomplete case reporting. Although we identified numerous examples of liver injury and death after repeated doses of acetaminophen, all the deaths and all but 6 cases of hepatic abnormalities involved doses more than 75 mg/kg per day. This study suggests that the doses of less than 75 mg/kg per day of acetaminophen are safe for children younger than 6 years.

  9. Immunochemical quantitation of 3-(cystein-S-yl)acetaminophen protein adducts in subcellular liver fractions following a hepatotoxic dose of acetaminophen.

    PubMed

    Pumford, N R; Roberts, D W; Benson, R W; Hinson, J A

    1990-08-01

    The hepatotoxicity of acetaminophen correlates with the formation of 3-(cystein-S-yl)acetaminophen protein adducts. Using a sensitive and specific immunochemical assay, we quantitated the formation of these protein adducts in liver fractions and serum after administration of a hepatotoxic dose of acetaminophen (400 mg/kg) to B6C3F1 mice. Adducts in the cytosolic fraction increased to 3.6 nmol/mg protein at 2 hr and then decreased to 1.1 nmol/mg protein by 8 hr. Concomitant with the decrease in adducts in the cytosol, 3-(cystein-S-yl)acetaminophen protein adducts appeared in serum and their levels paralleled increases in serum alanine aminotransferase. Microsomal protein adducts peaked at 1 hr (0.7 nmol/mg protein) and subsequently decreased to 0.2 nmol/mg at 8 hr. The 4000 g pellet (nuclei, plasma membranes, and cell debris) had the highest level of adducts (3.5 nmol/mg protein), which remained constant from 1 to 8 hr. Evaluation of fractions purified from a 960 g pellet indicated that the highest concentration of 3-(cystein-S-yl)acetaminophen protein adducts was located in plasma membranes and mitochondria; peak levels were 10.3 and 5.1 nmol/mg respectively. 3-(Cystein-S-yl)acetaminophen protein adducts were detected in nuclei only after enzymatic hydrolysis of the proteins. The localization of high levels of 3-(cystein-S-yl)acetaminophen protein adducts in plasma membranes and mitochondria may play a critical role in acetaminophen toxicity.

  10. Simultaneous determination of sulfation and glucuronidation of flavones in FVB mouse intestine in vitro and in vivo.

    PubMed

    Fan, Yanfang; Tang, Lan; Zhou, Juan; Feng, Qian; Xia, Bijun; Liu, Zhongqiu

    2013-04-01

    Glucuronidation and sulfation are the two major phase II metabolic pathways for flavones, natural compounds that hold great potential for improving human health. We investigated the positional preference for sulfation and glucuronidation of seven structurally similar flavones in vitro and in situ. An FVB mouse intestinal perfusion model was used in addition to three small intestine S9 fractions catalyzing sulfation only (Sult enzymes), glucuronidation only (Ugt enzymes) or both (Sult and Ugt enzymes). In both the single and co-reaction S9 systems, flavones containing 7-OH groups were conjugated only at 7-OH despite the presence of other hydroxyl groups, and 7-OH glucuronidation was faster than sulfation (P <0.05). The sulfation rate was enhanced in the Sult-Ugt co-reaction system, while glucuronidation was usually unchanged by the presence of Sult. In the intestinal perfusate, sulfation patterns were the same in the small intestine and colon, and the excretion rate of 7-O-sulfate was the fastest or second fastest. The excretion of 7-O-glucuronidates was faster in small intestine (P < 0.05) than in colon. The S9-mediated sulfation rates of the different flavones were significantly correlated with the excretion rates of the same flavones from perfused intestine. In conclusion, flavone glucuronidation and sulfation rates were sensitive to minor changes in molecular structure. In intestinal S9 fractions, both Ugts and Sults preferentially catalyzed reactions at 7-OH. The sulfation rate was significantly enhanced by simultaneous glucuronidation, but glucuronidation was unaltered by sulfation. Sulfation rates in mouse S9 fractions correlated with sulfation rates in perfused intestine.

  11. The Human UGT1A3 Enzyme Conjugates Norursodeoxycholic Acid into a C23-ester Glucuronide in the Liver*

    PubMed Central

    Trottier, Jocelyn; El Husseini, Diala; Perreault, Martin; Pâquet, Sophie; Caron, Patrick; Bourassa, Sylvie; Verreault, Mélanie; Inaba, Ted T.; Poirier, Guy G.; Bélanger, Alain; Guillemette, Chantal; Trauner, Michael; Barbier, Olivier

    2010-01-01

    Norursodeoxycholic acid (norUDCA) exhibits efficient anti-cholestatic properties in an animal model of sclerosing cholangitis. norUDCA is eliminated as a C23-ester glucuronide (norUDCA-23G) in humans. The present study aimed at identifying the human UDP-glucuronosyltransferase (UGT) enzyme(s) involved in hepatic norUDCA glucuronidation and at evaluating the consequences of single nucleotide polymorphisms in the coding region of UGT genes on norUDCA-23G formation. The effects of norUDCA on the formation of the cholestatic lithocholic acid-glucuronide derivative and of rifampicin on hepatic norUDCA glucuronidation were also explored. In vitro glucuronidation assays were performed with microsomes from human tissues (liver and intestine) and HEK293 cells expressing human UGT enzymes and variant allozymes. UGT1A3 was identified as the major hepatic UGT enzyme catalyzing the formation of norUDCA-23G. Correlation studies using samples from a human liver bank (n = 16) indicated that the level of UGT1A3 protein is a strong determinant of in vitro norUDCA glucuronidation. Analyses of the norUDCA-conjugating activity by 11 UGT1A3 variant allozymes identified three phenotypes with high, low, and intermediate capacity. norUDCA is also identified as a competitive inhibitor for the hepatic formation of the pro-cholestatic lithocholic acid-glucuronide derivative, whereas norUDCA glucuronidation is weakly stimulated by rifampicin. This study identifies human UGT1A3 as the major enzyme for the hepatic norUDCA glucuronidation and supports that some coding polymorphisms affecting the conjugating activity of UGT1A3 in vitro may alter the pharmacokinetic properties of norUDCA in cholestasis treatment. PMID:19889628

  12. In Vitro antioxidative activity of pumpkin seed (Cucurbita pepo) protein isolate and its In Vivo effect on alanine transaminase and aspartate transaminase in acetaminophen-induced liver injury in low protein fed rats.

    PubMed

    Nkosi, C Z; Opoku, A R; Terblanche, S E

    2006-09-01

    The antioxidative effects of pumpkin seed protein isolate (Cucurbita pepo) were investigated in vitro. The isolate exhibited about 80% radical scavenging activity, chelating activity of approximately 64% on Fe2+ ions and an inhibition of approximately 10% of xanthine oxidase. Subsequently the effects of the isolate on the plasma activity levels of alanine transaminase and aspartate transaminase against acetaminophen induced acute liver injury in low-protein fed male Sprague-Dawley rats were ascertained. The rats were maintained on a low-protein diet for 5 days and divided into three subgroups. Two subgroups were injected with acetaminophen and the other with an equivalent amount of polyethylene glycol 400. Two hours after intoxication one of the two subgroups was administered with the protein isolate. Rats from the different subgroups were killed at 24, 48 and 72 h after treatment. After 5 days on the low-protein diet the activity levels of the enzymes were significantly higher than their counterparts on a normal balanced diet. The administration of protein isolate after acetaminophen intoxication resulted in significantly reduced activity levels. It is concluded that the protein isolate has promising antioxidative properties. Furthermore, the isolate administration was effective in alleviating the detrimental effects associated with protein malnutrition and acetaminophen intoxication.

  13. Hepatoprotective, antioxidant, and ameliorative effects of ginger (Zingiber officinale Roscoe) and vitamin E in acetaminophen treated rats.

    PubMed

    Abdel-Azeem, Amal S; Hegazy, Amany M; Ibrahim, Khadiga S; Farrag, Abdel-Razik H; El-Sayed, Eman M

    2013-09-01

    Ginger is a remedy known to possess a number of pharmacological properties. This study investigated efficacy of ginger pretreatment in alleviating acetaminophen-induced acute hepatotoxicity in rats. Rats were divided into six groups; negative control, acetaminophen (APAP) (600 mg/kg single intraperitoneal injection); vitamin E (75 mg/kg), ginger (100 mg/kg), vitamin E + APAP, and ginger + APAP. Administration of APAP elicited significant liver injury that was manifested by remarkable increase in plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), arginase activities, and total bilirubin concentration. Meanwhile, APAP significantly decreased plasma total proteins and albumin levels. APAP administration resulted in substantial increase in each of plasma triacylglycerols (TAGs), malondialdhyde (MDA) levels, and total antioxidant capacity (TAC). However, ginger or vitamin E treatment prior to APAP showed significant hepatoprotective effect by lowering the hepatic marker enzymes (AST, ALT, ALP, and arginase) and total bilirubin in plasma. In addition, they remarkably ameliorated the APAP-induced oxidative stress by inhibiting lipid peroxidation (MDA). Pretreatment by ginger or vitamin E significantly restored TAGs, and total protein levels. Histopathological examination of APAP treated rats showed alterations in normal hepatic histoarchitecture, with necrosis and vacuolization of cells. These alterations were substantially decreased by ginger or vitamin E. Our results demonstrated that ginger can prevent hepatic injuries, alleviating oxidative stress in a manner comparable to that of vitamin E. Combination therapy of ginger and APAP is recommended especially in cases with hepatic disorders or when high doses of APAP are required.

  14. Microstructural investigation using synchrotron radiation X-ray microtomography reveals taste-masking mechanism of acetaminophen microspheres.

    PubMed

    Guo, Zhen; Yin, Xianzhen; Liu, Congbiao; Wu, Li; Zhu, Weifeng; Shao, Qun; York, Peter; Patterson, Laurence; Zhang, Jiwen

    2016-02-29

    The structure of solid drug delivery systems has considerable influence on drug release behaviors from particles and granules and also impacts other properties relevant to release characteristics such as taste. In this study, lipid-based microspheres of acetaminophen were prepared to mask the undesirable taste of drug and therefore to identify the optimal formulation for drug release. Synchrotron radiation X-ray computed microtomography (SR-μCT) was used to investigate the fine structural architectures of microspheres non-destructively at different sampling times during drug release test, which were simultaneously determined to quantitatively correlate the structural data with drug release behaviors. The results demonstrated that the polymeric formulation component, namely, cationic polymethacrylate (Eudragit E100), was the key factor to mask the bitter taste of acetaminophen by inhibiting immediate drug release thereby reducing the interaction intensity of the bitter material with the oral cavity taste buds. The structure and morphology of the microspheres were found to be influenced by the shape and particle size of the drug, which was also an important factor for taste-masking performance. The quantitative analysis generated detailed structural information which was correlated well with drug release behaviors. Thus, SR-μCT has been proved as a powerful tool to investigate the fine microstructure of particles and provides a new approach in the design of particles for taste masking.

  15. Dual role of acetaminophen in promoting hepatoma cell apoptosis and kidney fibroblast proliferation

    PubMed Central

    YU, YUNG-LUEN; YIANG, GIOU-TENG; CHOU, PEI-LUN; TSENG, HSU-HUNG; WU, TSAI-KUN; HUNG, YU-TING; LIN, PEI-SHIUAN; LIN, SHU-YU; LIU, HSIAO-CHUN; CHANG, WEI-JUNG; WEI, CHYOU-WEI

    2014-01-01

    Acetaminophen (APAP), is a safe analgesic and antipyretic drug at therapeutic dose, and is widely used in the clinic. However, high doses of APAP can induce hepatotoxicity and nephrotoxicity. Most studies have focused on high-dose APAP-induced acute liver and kidney injury. So far, few studies have investigated the effects of the therapeutic dose (1/10 of the high dose) or of the low dose (1/100 of the high dose) of APAP on the cells. The aim of this study was to investigate the cellular effects of therapeutic- or low-dose APAP treatment on hepatoma cells and kidney fibroblasts. As expected, high-dose APAP treatment inhibited while therapeutic and low-dose treatment did not inhibit cell survival of kidney tubular epithelial cells. In addition, therapeutic-dose treatment induced an increase in the H2O2 level, activated the caspase-9/-3 cascade, and induced cell apoptosis of hepatoma cells. Notably, APAP promoted fibroblast proliferation, even at low doses. This study demonstrates that different cellular effects are exerted upon treatment with different APAP concentrations. Our results indicate that treatment with the therapeutic dose of APAP may exert an antitumor activity on hepatoma, while low-dose treatment may be harmful for patients with fibrosis, since it may cause proliferation of fibroblasts. PMID:24682227

  16. In vitro evaluation of the effects of anti-fungals, benzodiazepines and non-steroidal anti-inflammatory drugs on the glucuronidation of 19-norandrosterone: implications on doping control analysis.

    PubMed

    Palermo, Amelia; Alessi, Beatrice; Botrè, Francesco; de la Torre, Xavier; Fiacco, Ilaria; Mazzarino, Monica

    2016-09-01

    We have studied whether the phase II metabolism of 19-norandrosterone, the most representative metabolite of 19-nortestosterone (nandrolone), can be altered in the presence of other drugs that are not presently included on the Prohibited List of the World Anti-Doping Agency. In detail, we have evaluated the effect of non-prohibited drugs belonging to the classes of anti-fungals, benzodiazepines, and non-steroidal anti-inflammatory drugs on the glucuronidation of 19-norandrosterone. In vitro assays based on the use of either pooled human liver microsomes or specific recombinant isoforms of uridine diphosphoglucuronosyl-transferase were designed and performed to monitor the formation of 19-norandrosterone glucuronide from 19-norandrosterone. Determination of 19-norandrosterone (free and conjugated fraction) was performed by gas chromatography - mass spectrometry after sample pretreatment consisting of an enzymatic hydrolysis (performed only for the conjugated fraction), liquid/liquid extraction with tert-butylmethyl ether, and derivatization to form the trimethylsilyl derivative. In parallel, a method based on reversed-phase liquid chromatography coupled to tandem mass spectrometry in positive electrospray ionization with acquisition in selected reaction monitoring mode was also developed to identify the non-prohibited drugs considered in this study. Incubation experiments have preliminarily shown that the glucuronidation of 19-norandrosterone is principally carried out by UGT2B7 (39%) and UGT2B17 (31%). Inhibition studies have shown that the yield of the glucuronidation reaction is reduced in the presence of the anti-fungals itraconazole, ketoconazole, and miconazole, of the benzodiazepine triazolam and of the non-steroidal anti-inflammatory drugs diclofenac and ibuprofen, while no alteration was recorded in the presence of all other compounds considered in this study. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Influence of acetaminophen on performance during time trial cycling.

    PubMed

    Mauger, Alexis R; Jones, Andrew M; Williams, Craig A

    2010-01-01

    To establish whether acetaminophen improves performance of self-paced exercise through the reduction of perceived pain, 13 trained male cyclists performed a self-paced 10-mile (16.1 km) cycle time trial (TT) following the ingestion of either acetaminophen (ACT) or a placebo (PLA), administered in randomized double-blind design. TT were completed in a significantly faster time (t(12) = 2.55, P < 0.05) under the ACT condition (26 min 15 s +/- 1 min 36 s vs. 26 min 45 s +/- 2 min 2 s). Power output (PO) was higher during the middle section of the TT in the ACT condition, resulting in a higher mean PO (P < 0.05) (265 +/- 12 vs. 255 +/- 15 W). Blood lactate concentration (B[La]) and heart rate (HR) were higher in the ACT condition (B[La] = 6.1 +/- 2.9 mmol/l; HR = 87 +/- 7%max) than in the PLA condition (B[La] = 5.1 +/- 2.6 mmol/l; HR = 84 +/- 9%max) (P < 0.05). No significant difference in rating of perceived exertion (ACT = 15.5 +/- 0.2; PLA = 15.7 +/- 0.2) or perceived pain (ACT = 5.6 +/- 0.2; PLA = 5.5 +/- 0.2) (P > 0.05) was observed. Using acetaminophen, participants cycled at a higher mean PO, with an increased HR and B[La], but without changes in perceived pain or exertion. Consequently, completion time was significantly faster. These findings support the notion that exercise is regulated by pain perception, and increased pain tolerance can improve exercise capacity.

  18. Implications of Sensorineural Hearing Loss With Hydrocodone/Acetaminophen Abuse

    PubMed Central

    Novac, Andrei; Iosif, Anamaria M.; Groysman, Regina; Bota, Robert G.

    2015-01-01

    Sensorineural hearing loss is an infrequently recognized side effect of pain medication abuse. Chronic pain patients treated with opiates develop different degrees of tolerance to pain medications. In many cases, the tolerance becomes the gateway to a variety of cycles of overuse and unmasking of significant psychiatric morbidity and mortality. An individualized approach utilizing combined treatment modalities (including nonopiate pharmaceuticals) is expected to become the norm. Patients can now be provided with multidisciplinary care that addresses an individual’s psychiatric, social, and medical needs, which requires close cooperation between physicians of varying specialties. This report describes a patient who experienced hearing loss from hydrocodone/acetaminophen abuse. PMID:26835162

  19. Inhibitor of apoptosis signal-regulating kinase 1 protects against acetaminophen-induced liver injury

    SciTech Connect

    Xie, Yuchao; Ramachandran, Anup; Breckenridge, David G.; Liles, John T.; Lebofsky, Margitta; Farhood, Anwar; Jaeschke, Hartmut

    2015-07-01

    Metabolic activation and oxidant stress are key events in the pathophysiology of acetaminophen (APAP) hepatotoxicity. The initial mitochondrial oxidative stress triggered by protein adduct formation is amplified by c-jun-N-terminal kinase (JNK), resulting in mitochondrial dysfunction and ultimately cell necrosis. Apoptosis signal-regulating kinase 1 (ASK1) is considered the link between oxidant stress and JNK activation. The objective of the current study was to assess the efficacy and mechanism of action of the small-molecule ASK1 inhibitor GS-459679 in a murine model of APAP hepatotoxicity. APAP (300 mg/kg) caused extensive glutathione depletion, JNK activation and translocation to the mitochondria, oxidant stress and liver injury as indicated by plasma ALT activities and area of necrosis over a 24 h observation period. Pretreatment with 30 mg/kg of GS-459679 almost completely prevented JNK activation, oxidant stress and injury without affecting the metabolic activation of APAP. To evaluate the therapeutic potential of GS-459679, mice were treated with APAP and then with the inhibitor. Given 1.5 h after APAP, GS-459679 was still protective, which was paralleled by reduced JNK activation and p-JNK translocation to mitochondria. However, GS-459679 treatment was not more effective than N-acetylcysteine, and the combination of GS-459679 and N-acetylcysteine exhibited similar efficacy as N-acetylcysteine monotherapy, suggesting that GS-459769 and N-acetylcysteine affect the same pathway. Importantly, inhibition of ASK1 did not impair liver regeneration as indicated by PCNA staining. In conclusion, the ASK1 inhibitor GS-459679 protected against APAP toxicity by attenuating JNK activation and oxidant stress in mice and may have therapeutic potential for APAP overdose patients. - Highlights: • Two ASK1 inhibitors protected against acetaminophen-induced liver injury. • The ASK1 inhibitors protect when used as pre- or post-treatment. • Protection by ASK1 inhibitor is

  20. Simultaneous Quantification of Buprenorphine, Norbuprenorphine, Buprenorphine-Glucuronide and Norbuprenorphine-Glucuronide in Human Umbilical Cord by Liquid Chromatography Tandem Mass Spectrometry

    PubMed Central

    Concheiro, Marta; Shakleya, Diaa M.; Huestis, Marilyn A.

    2009-01-01

    A LCMS method was developed and validated for the simultaneous determination of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc) and norbuprenorphine glucuronide (NBUP-Gluc) in human umbilical cord. Quantification was achieved by selected ion monitoring of precursor ions m/z 468.4 for BUP; 414.3 for NBUP; 644.4 for BUP-Gluc and 590 for NBUP-Gluc. BUP and NBUP were identified by MS2, with m/z 396, 414 and 426 for BUP, and m/z 340, 364 and 382 for NBUP. Glucuronide conjugates were identified by MS3 with m/z 396 and 414 for BUP-Gluc and m/z 340 and 382 for NBUP-Gluc. The assay was linear 1–50 ng/g. Intra, inter-day and total assay imprecision (%RSD) were <14.5%, and analytical recovery ranged from 94.1% to 112.3% for all analytes. Extraction efficiencies were >66.3%, and process efficiency >73.4%. Matrix effect ranged, in absolute value, from 3.7% to 27.4% (CV<21.8%, n=8). The method was selective with no endogenous or exogenous interferences from 41 compounds evaluated. Sensitivity was high with limits of detection of 0.8 ng/g. In order to prove method applicability, an authentic umbilical cord obtained from an opioid-dependent pregnant woman receiving BUP pharmacotherapy was analyzed. Interestingly, BUP was not detected but concentrations of the other metabolites were NBUP-Gluc 13.4 ng/g, BUP-Gluc 3.5 ng/g and NBUP 1.2 ng/g. PMID:19406593

  1. Prophylactic and Therapeutic Potential of Acetyl-L-carnitine against Acetaminophen-Induced Hepatotoxicity in Mice.

    PubMed

    Alotaibi, Salman A; Alanazi, Abdulrazaq; Bakheet, Saleh A; Alharbi, Naif O; Nagi, Mahmoud N

    2016-01-01

    Prophylactic and therapeutic effects of acetylcarnitine against acetaminophen-induced hepatotoxicity were studied in mice. To evaluate the prophylactic effects of acetylcarnitine, mice were supplemented with acetylcarnitine (2 mmol/kg/day per oral (p.o.) for 5 days) before a single dose of acetaminophen (350 mg/kg intraperitoneal (i.p.)). Animals were sacrificed 6 h after acetaminophen injection. Acetaminophen significantly increased the markers of liver injury, hepatic reactive oxygen species, and nitrate/nitrite, and decreased hepatic glutathione (GSH) and the antioxidant enzymes. Acetylcarnitine supplementation resulted in reversal of all biochemical parameters toward the control values. To explore the therapeutic effects of acetylcarnitine, mice were given a single dose of acetylcarnitine (0.5, 1, and 2 mmol/kg p.o.) 1.5 h after acetaminophen. Animals were sacrificed 6 h after acetaminophen. Acetylcarnitine administration resulted in partial reversal of liver injury only at 2 mmol/kg p.o. At equimolar doses, N-acetylcystiene was superior as therapeutic agent to acetylcarnitine. However, acetylcarnitine potentiated the effect of N-acetylcystiene in the treatment of acetaminophen toxicity.

  2. Use of acetaminophen in relation to the occurrence of cancer: a review of epidemiologic studies.

    PubMed

    Weiss, Noel S

    2016-12-01

    Acetaminophen has several pharmacologic properties that suggest it could be carcinogenic in human beings. A number of epidemiologic studies have been conducted to examine whether use of acetaminophen actually predisposes to the occurrence of one or more forms of cancer. There are inherent limitations to many of these studies, including the inaccurate identification of users and nonusers of acetaminophen, relatively short follow-up for cancer incidence, and the potential for confounding by indication. The present manuscript reviews the results of epidemiologic studies of acetaminophen use in relation to cancer incidence published through the end of 2015. The limitations of the underlying studies notwithstanding, some interim conclusions can be reached. For all but several forms of cancer, there is no suggestion that persons who have taken acetaminophen are at altered risk, even persons who have consumed a large quantity of the drug or those who have taken it for an extended duration. While in some studies the incidence of renal cell carcinoma has been observed to be increased among acetaminophen users, several other studies have failed to observe any such association; the reason for the discrepant findings is unclear. Some of the small number of studies that have presented data on the incidence of lymphoma, leukemia, and plasma cell disorders have found the risk to be modestly higher in users than nonusers of acetaminophen, but the results of other studies of these malignancies will be needed to gauge the possible role of publication bias as the basis for the positive results.

  3. Application of microdialysis to evaluate the efflux transport of estradiol 17-beta glucuronide across the rat blood-retinal barrier.

    PubMed

    Katayama, Kazunori; Ohshima, Yuki; Tomi, Masatoshi; Hosoya, Ken-ichi

    2006-09-30

    The purpose of the present study was to evaluate vitreous humor/retina-to-blood efflux transport in rats and determine the efflux transport of estradiol 17-beta glucuronide (E17betaG) across the blood-retinal barrier (BRB) by the use of microdialysis. [(3)H]E17betaG and [(14)C]D-mannitol, which were used as a model compound for amphipathic organic anions and a bulk flow marker, respectively, were injected into the vitreous humor of rat eye, and a microdialysis probe was placed in the vitreous humor. [(3)H]E17betaG and [(14)C]D-mannitol were bi-exponentially eliminated from the vitreous humor after vitreous bolus injection. The elimination rate constant of [(3)H]E17betaG during the terminal phase was 1.9-fold greater than that of [(14)C]D-mannitol and reduced the level of [(14)C]D-mannitol in the retinal presence of 0.3 mM E17betaG, suggesting that [(3)H]E17betaG is transported via a carrier-mediated efflux transport process across the BRB. The efflux transport of [(3)H]E17betaG was significantly inhibited by organic anions, such as probenecid, sulfobromophthalein, digoxin, and dehydroepiandrosterone sulfate, whereas it was not inhibited by p-aminohippuric acid. In conclusion, the efflux transport of [(3)H]E17betaG across the rat BRB was evaluated by microdialysis and its inhibition by organic anions suggests organic anion transporting polypeptide 1a4-mediated E17betaG efflux transport at the BRB.

  4. Effects of Andrographis paniculata and Orthosiphon stamineus extracts on the glucuronidation of 4-methylumbelliferone in human UGT isoforms.

    PubMed

    Ismail, Sabariah; Hanapi, Nur Aziah; Ab Halim, Mohd Rohaimi; Uchaipichat, Verawan; Mackenzie, Peter I

    2010-05-14

    The effects of Andrographis paniculata and Orthosiphon stamineus extracts on the in vitro glucuronidation of 4-methylumbelliferone (4MU) by recombinant human UGTs, UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A10, UGT2B7 and UGT2B15 were determined. The potential inhibitory effects of both of the extracts on the activity of each of the UGT isoforms were investigated using 4MU as the substrate. Incubations contained UDP-glucuronic acid (UDPGA) as the cofactor, MgCl(2), cell lysate of respective isoform, and 4MU at the approximate apparent K(m) or S(50) value of each isoform. Final concentrations of Andrographis paniculata and Orthosiphon stamineus extracts used were 0.025, 0.25, 2.5, 25 and 50 microg/mL and 0.01, 0.10, 1.0, 10 and 50 microg/mL respectively. Both extracts variably inhibited the activity of most of the isoforms in a concentration dependent manner. Andrographis paniculata extract was the better inhibitor of all the isoforms studied (IC(50) 1.70 microg/mL for UGT1A3, 2.57 microg/mL for UGT1A8, 2.82 microg/mL for UGT2B7, 5.00 micorg/mL for UGT1A1, 5.66 microg/mL for UGT1A6, 9.88 microg/mL for UGT1A7 and 15.66 microg/mL for UGT1A10). Both extracts showed less than 70% inhibition of UGT2B15, so the IC(50) values were >50 microg/mL. The inhibition of human UGTs by Andrographis paniculata and Orthosiphon stamineus extracts in vitro suggests a potential for drug-herbal extract interactions in the therapeutic setting.

  5. Post-mortem levels and tissue distribution of codeine, codeine-6-glucuronide, norcodeine, morphine and morphine glucuronides in a series of codeine-related deaths.

    PubMed

    Frost, Joachim; Løkken, Trine Nordgård; Helland, Arne; Nordrum, Ivar Skjåk; Slørdal, Lars

    2016-05-01

    This article presents levels and tissue distribution of codeine, codeine-6-glucuronide (C6G), norcodeine, morphine and the morphine metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in post-mortem blood (peripheral and heart blood), vitreous fluid, muscle, fat and brain tissue in a series of 23 codeine-related fatalities. CYP2D6 genotype is also determined and taken into account. Quantification of codeine, C6G, norcodeine, morphine, M3G and M6G was performed with a validated solid phase extraction LC-MS method. The series comprise 19 deaths (83%) attributed to mixed drug intoxication, 4 deaths (17%) attributed to other causes of death, and no cases of unambiguous monointoxication with codeine. The typical peripheral blood concentration pattern in individual cases was C6G≫codeine≫norcodeine>morphine, and M3G>M6G>morphine. In matrices other than blood, the concentration pattern was similar, although in a less systematic fashion. Measured concentrations were generally lower in matrices other than blood, especially in brain and fat, and in particular for the glucuronides (C6G, M3G and M6G) and, to some extent, morphine. In brain tissue, the presumed active moieties morphine and M6G were both below the LLOQ (0.0080mg/L and 0.058mg/L, respectively) in a majority of cases. In general, there was a large variability in both measured concentrations and calculated blood/tissue concentration ratios. There was also a large variability in calculated ratios of morphine to codeine, C6G to codeine and norcodeine to codeine in all matrices, and CYP2D6 genotype was not a reliable predictor of these ratios. The different blood/tissue concentration ratios showed no systematic relationship with the post-mortem interval. No coherent degradation or formation patterns for codeine, morphine, M3G and M6G were observed upon reanalysis in peripheral blood after storage.

  6. Interaction of the electrophilic ketoprofenyl-glucuronide and ketoprofenyl-coenzyme A conjugates with cytosolic glutathione S-transferases.

    PubMed

    Osbild, Sandra; Bour, Jérome; Maunit, Benoît; Guillaume, Cécile; Asensio, Carine; Muller, Jean-François; Netter, Patrick; Kirsch, Glbert; Bagrel, Denyse; Lapicque, Françoise; Battaglia, Eric

    2008-02-01

    Carboxylic acid-containing drugs are metabolized mainly through the formation of glucuronide and coenzyme A esters. These conjugates have been suspected to be responsible for the toxicity of several nonsteroidal anti-inflammatory drugs because of the reactivity of the electrophilic ester bond. In the present study we investigated the reactivity of ketoprofenyl-acylglucuronide (KPF-OG) and ketoprofenyl-acyl-coenzyme A (KPF-SCoA) toward cytosolic rat liver glutathione S-transferases (GST). We observed that KPF-SCoA, but not KPF-OG inhibited the conjugation of 1-chloro-2,4-dinitrobenzene and 4-nitroquinoline N-oxide catalyzed by both purified cytosolic rat liver GST and GST from FAO and H5-6 rat hepatoma cell lines. Photoaffinity labeling with KPF-SCoA suggested that the binding of this metabolite may overlap the binding site of 4-methylumbelliferone sulfate. Furthermore, high-performance liquid chromatography and mass spectrometry analysis showed that both hydrolysis and transacylation reactions were observed in the presence of GST and glutathione. The formation of ketoprofenyl-S-acyl-glutathione could be kinetically characterized (apparent K(m) = 196.0 +/- 70.6 microM). It is concluded that KPF-SCoA is both a GST inhibitor and a substrate of a GST-dependent transacylation reaction. The reactivity and inhibitory potency of thioester CoA derivatives toward GST may have potential implications on the reported in vivo toxicity of some carboxylic acid-containing drugs.

  7. Pregnane × Receptor (PXR) expression in colorectal cancer cells restricts irinotecan chemosensitivity through enhanced SN-38 glucuronidation

    PubMed Central

    2010-01-01

    Background Clinical efficacy of chemotherapy in colorectal cancer is subjected to broad inter-individual variations leading to the inability to predict outcome and toxicity. The topoisomerase I inhibitor irinotecan (CPT-11) is worldwide approved for the treatment of metastatic colorectal cancer and undergoes extensive peripheral and tumoral metabolism. PXR is a xenoreceptor activated by many drugs and environmental compounds regulating the expression of drug metabolism and transport genes in detoxification organs such as liver and gastrointestinal tract. Considering the metabolic pathway of irinotecan and the tissue distribution of Pregnane × Receptor (PXR), we hypothesized that PXR could play a key role in colon cancer cell response to irinotecan. Results PXR mRNA expression was quantified by RT-quantitative PCR in a panel of 14 colon tumor samples and their matched normal tissues. PXR expression was modulated in human colorectal cancer cells LS174T, SW480 and SW620 by transfection and siRNA strategies. Cellular response to irinotecan and its active metabolic SN38 was assessed by cell viability assays, HPLC metabolic profiles and mRNA quantification of PXR target genes. We showed that PXR was strongly expressed in colon tumor samples and displayed a great variability of expression. Expression of hPXR in human colorectal cancer cells led to a marked chemoresistance to the active metabolite SN38 correlated with PXR expression level. Metabolic profiles of SN38 showed a strong enhancement of SN38 glucuronidation to the inactive SN38G metabolite in PXR-expressing cells, correlated with an increase of UDPglucuronosyl transferases UGT1A1, UGT1A9 and UGT1A10 mRNAs. Inhibition of PXR expression by lentivirus-mediated shRNA, led to SN38 chemoresistance reversion concomitantly to a decrease of UGT1A1 expression and SN38 glucuronidation. Similarly, PXR mRNA expression levels correlated to UGT1A subfamily expression in human colon tumor biopsies. Conclusion Our results

  8. The development of a high-performance liquid chromatography-tandem mass spectrometric method for simultaneous quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine in serum

    PubMed Central

    Sartori, David; Lewis, Tamorah; Breaud, Autumn; Clarke, William

    2015-01-01

    Objectives Development and validation of a selective, robust high-performance liquid chromatography-tandem mass spectrometric (HPLC/MS-MS) method for the quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine in human serum. Design and methods Drug-free human serum samples spiked with morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine were prepared by protein precipitation using methanol containing the internal standards. Samples were injected onto a Thermo Scientific AccuCore PFP column for chromatographic separation. Detection was achieved using a Thermo Scientific TSQ Vantage mass spectrometer. Assay validation followed the new Clinical and Laboratory Standards Institute (CLSI) C62-A guidelines. Results The analytical measuring range for all analytes was determined to be 5 to 1,000 ng/mL. Intra- and inter-assay precision for three quality control levels were ≤ 7.0% and ≤ 13.5%, respectively. Carryover, stability, linearity, matrix effects, extraction and processing efficiency and method comparison characteristics were acceptable relative to the CLSI C62 guidelines. Conclusion The validation of this HPLC-MS/MS method demonstrated a robust and rapid assay for the quantification of morphine, morphine-3-β-glucuronide, morphine-6-β-glucuronide, hydromorphone, and normorphine. PMID:26118474

  9. Variability in Acetaminophen Labeling Practices: a Missed Opportunity to Enhance Patient Safety.

    PubMed

    King, Jennifer P; McCarthy, Danielle M; Serper, Marina; Jacobson, Kara L; Mullen, Rebecca J; Parker, Ruth M; Wolf, Michael S

    2015-12-01

    Confusion regarding a drug's active ingredient may lead to simultaneous use of multiple acetaminophen-containing prescriptions and increase the risk of unintentional overdose. The objective of this study was to examine prescription labeling practices for commonly prescribed acetaminophen-containing analgesics, specifically focusing on how active ingredient information and concomitant use warnings were conveyed. Patients with new acetaminophen-containing prescriptions were recruited upon discharge from an emergency department in Chicago or at an outpatient, hospital-based pharmacy in Atlanta. Label information was transcribed from prescription bottles and patients' knowledge of active ingredient was assessed by in-person interviews. Among the 245 acetaminophen-containing prescriptions, hydrocodone was the most common second active ingredient (n = 208, 84.8 %) followed by oxycodone (n = 28, 11.4 %). Acetaminophen was identified by its full name on 6.9 % (n = 17) of labels; various abbreviations were used in 93.1 % of cases. One hundred forty-seven bottles used auxiliary warning labels with the majority of labels (n = 130, 88.4 %) warning about maximum dose and 11.5 % (n = 17) about concomitant use. Most of the study participants (n = 177, 72.2 %) were not able to identify acetaminophen as an active ingredient in their prescription. There was no significant association between the use of unabbreviated labels including warning information and patients' awareness of acetaminophen as an active ingredient (36.4 vs. 27.3 %, p = 0.50). We noted high variability in labeling practices and warning information conveyed to patients receiving acetaminophen-containing prescriptions. Missed opportunities to adequately convey risk information may contribute to the burden of acetaminophen-related liver injury.

  10. Use of acetaminophen (paracetamol) during pregnancy and the risk of autism spectrum disorder in the offspring.

    PubMed

    Andrade, Chittaranjan

    2016-02-01

    Acetaminophen (paracetamol) is available over the counter in most countries and is widely considered to be safe for use during pregnancy; studies report gestational exposures to acetaminophen that lie in the 46%-65% range. Acetaminophen influences inflammatory and immunologic mechanisms and may predispose to oxidative stress; these and other effects are hypothesized to have the potential to compromise neurodevelopment in the fetal and infant brain. Two ecological studies suggested that population-level trends in the use of acetaminophen were associated with trends in the incidence/prevalence of autism; one of these studies specifically examined acetaminophen use during pregnancy. One large prospective observational cohort study found that gestational exposure to acetaminophen (especially when the duration of exposure was 28 days or more) was associated with motor milestone delay, gross and fine motor impairments, communication impairment, impairments in internalizing and externalizing behaviors, and hyperactivity, all at age 3 years; however, social and emotional developmental behaviors were mostly unaffected. A very recent large cohort study with a 12.7-year follow-up found that gestational exposure to acetaminophen was associated with an increased risk of autism spectrum disorder, but only when a hyperkinetic disorder was also present. In the light of existing data associating acetaminophen use during pregnancy and subsequent risk of attention-deficit/hyperactivity disorder, this new finding suggests that the predisposition, if any, is toward the hyperkinetic syndrome rather than to autism. In summary, the empirical data are very limited, but whatever empirical data exist do not support the suggestion that the use of acetaminophen during pregnancy increases the risk of autism in the offspring.

  11. Study on the reaction mechanism and the static injection chemiluminescence method for detection of acetaminophen.

    PubMed

    Wu, Yongjun; Zhang, Huili; Yu, Songcheng; Yu, Fei; Li, Yanqiang; Zhang, Hongquan; Qu, Lingbo; Harrington, Peter de B

    2013-01-01

    Acetaminophen, also called paracetamol, is found in Tylenol, Excedrin and other products as over-the-counter medicines. In this study, acetaminophen as a luminol signal enhancer was used in the chemiluminescence (CL) substrate solution of horseradish peroxidase (HRP) for the first time. The use of acetaminophen in the luminol-HRP-H2O2 system affected not only the intensity of the obtained signal, but also its kinetics. It was shown that acetaminophen was to be a potent enhancer of the luminol-HRP-H2O2 system. A putative enhancement mechanism for the luminol-H2O2-HRP-acetaminophen system is presented. The resonance of the nucleophilic amide group and the benzene ring of acetaminophen structure have a great effect on O-H bond dissociation energy of the phenol group and therefore on phenoxyl radical stabilization. These radicals act as mediators between HRP and luminol in an electron transfer reaction that generates luminol radicals and subsequently light emission, in which the intensity of CL is enhanced in the presence of acetaminophen. In addition, a simple method was developed to detect acetaminophen by static injection CL based on the enhanced CL system of luminol-H2O2-HRP by acetaminophen. Experimental conditions, such as pH and concentrations of substrates, have been examined and optimized. The proposed method exhibited good performance, the linear range was from 0.30 to 7.5 mM, the relative standard deviation was 1.86% (n = 10), limit of detection was 0.16 mM and recovery was 99 ± 4%.

  12. Direct Evidence of Acetaminophen Interference with Subcutaneous Glucose Sensing in Humans: A Pilot Study

    PubMed Central

    Basu, Ananda; Veettil, Sona; Dyer, Roy; Peyser, Thomas

    2016-01-01

    Abstract Background: Recent advances in accuracy and reliability of continuous glucose monitoring (CGM) devices have focused renewed interest on the use of such technology for therapeutic dosing of insulin without the need for independent confirmatory blood glucose meter measurements. An important issue that remains is the susceptibility of CGM devices to erroneous readings in the presence of common pharmacologic interferences. We report on a new method of assessing CGM sensor error to pharmacologic interferences using the example of oral administration of acetaminophen. Materials and Methods: We examined the responses of several different Food and Drug Administration–approved and commercially available CGM systems (Dexcom [San Diego, CA] Seven® Plus™, Medtronic Diabetes [Northridge, CA] Guardian®, and Dexcom G4® Platinum) to oral acetaminophen in 10 healthy volunteers without diabetes. Microdialysis catheters were placed in the abdominal subcutaneous tissue. Blood and microdialysate samples were collected periodically and analyzed for glucose and acetaminophen concentrations before and after oral ingestion of 1 g of acetaminophen. We compared the response of CGM sensors with the measured acetaminophen concentrations in the blood and interstitial fluid. Results: Although plasma glucose concentrations remained constant at approximately 90 mg/dL (approximately 5 mM) throughout the study, CGM glucose measurements varied between approximately 85 to 400 mg/dL (from approximately 5 to 22 mM) due to interference from the acetaminophen. The temporal profile of CGM interference followed acetaminophen concentrations measured in interstitial fluid (ISF). Conclusions: This is the first direct measurement of ISF concentrations of putative CGM interferences with simultaneous measurements of CGM performance in the presence of the interferences. The observed interference with glucose measurements in the tested CGM devices coincided temporally with appearance of

  13. Characterization of raloxifene glucuronidation: potential role of UGT1A8 genotype on raloxifene metabolism in vivo.

    PubMed

    Sun, Dongxiao; Jones, Nathan R; Manni, Andrea; Lazarus, Philip

    2013-07-01

    Raloxifene is a second-generation selective estrogen receptor modulator used for the prevention and treatment of osteoporosis and the prevention of breast cancer in postmenopausal women. Raloxifene is extensively metabolized by glucuronidation to form raloxifene-6-glucuronide (ral-6-Gluc) and raloxifene-4'-glucuronide (ral-4'-Gluc). The goal of the present study was to determine whether functional polymorphisms in active UGTs could play a role in altered raloxifene glucuronidation in vivo. Using homogenates from HEK293 UGT-overexpressing cell lines, raloxifene was shown to be glucuronidated primarily by the hepatic UGTs 1A1 and 1A9 and the extra-hepatic UGTs 1A8 and 1A10; no detectable raloxifene glucuronidation activity was found for UGT2B enzymes. Functional UGT1A1 transcriptional promoter genotypes were significantly (Ptrend = 0.005) associated with ral-6-Gluc formation in human liver microsomes, and, consistent with the decreased raloxifene glucuronidation activities observed in vitro with cell lines overexpressing UGT1A8 variants, the UGT1A8*2 variant was significantly (P = 0.023) correlated with total raloxifene glucuronide formation in human jejunum homogenates. While ral-4'-Gluc exhibited 1:100th the anti-estrogenic activity of raloxifene itself as measured by binding to the estrogen receptor, raloxifene glucuronides comprised about 99% of the circulating raloxifene dose in raloxifene-treated subjects, with ral-4'-Gluc comprising ~70% of raloxifene glucuronides. Plasma ral-6-Gluc (Ptrend = 0.0025), ral-4'-Gluc (Ptrend = 0.001), and total raloxifene glucuronides (Ptrend = 0.001) were increased in raloxifene-treated subjects who were predicted slow metabolizers [UGT1A8 (*1/*3)] versus intermediate metabolizers [UGT1A8 (*1/*1) or UGT1A8 (*1/*2)] versus fast metabolizers [UGT1A8 (*2/*2). These data suggest that raloxifene metabolism may be dependent on UGT1A8 genotype and that UGT1A8 genotype may play an important role in overall response to raloxifene.

  14. Missed paracetamol (acetaminophen) overdose due to confusion regarding drug names.

    PubMed

    Hewett, David G; Shields, Jennifer; Waring, W Stephen

    2013-07-01

    Immediate management of drug overdose relies upon the patient account of what was ingested and how much. Paracetamol (acetaminophen) is involved in around 40% of intentional overdose episodes, and remains the leading cause of acute liver failure in many countries including the United Kingdom. In recent years, consumers have had increasing access to medications supplied by international retailers via the internet, which may have different proprietary or generic names than in the country of purchase. We describe a patient that presented to hospital after intentional overdose involving 'acetaminophen' purchased via the internet. The patient had difficulty recalling the drug name, which was inadvertently attributed to 'Advil', a proprietary non-steroidal anti-inflammatory drug. The error was later recognised when the drug packaging became available, but the diagnosis of paracetamol overdose and initiation of acetylcysteine antidote were delayed. This case illustrates the benefit of routinely measuring paracetamol concentrations in all patients with suspected poisoning, although this is not universally accepted in practice. Moreover, it highlights the importance of the internet as a source of medications for intentional overdose, and emphasises the need for harmonisation of international drug names to improve patient safety.

  15. Soy isoflavone metabolism in cats compared with other species: Urinary metabolite concentrations and glucuronidation by liver microsomes

    PubMed Central

    Redmon, Joanna M.; Shrestha, Binu; Cerundolo, Rosario; Court, Michael H.

    2016-01-01

    Soybean is a common source of protein in many pet foods. Slow glucuronidation of soy-derived isoflavones in cats has been hypothesized to result in accumulation with adverse health consequences. Here we evaluated species’ differences in soy isoflavone glucuronidation using urine samples from cats and dogs fed a soy-based diet and liver microsomes from cats compared with microsomes from 12 other species.Significant concentrations of conjugated (but not unconjugated) genistein, daidzein, and glycitein, and the gut microbiome metabolites, dihydrogenistein and dihydrodaidzein were found in cat and dog urine samples. Substantial amounts of conjugated equol were also found in cat urine but not in dog urine.β-glucuronidase treatment showed that all these compounds were significantly glucuronidated in dog urine while only daidzein (11%) and glycitein (37%) showed any glucuronidation in cat urine suggesting that alternate metabolic pathways including sulfation predominate in cats.Glucuronidation rates of genistein, daidzein, and equol by cat livers were consistently ranked within the lowest three out of 13 species’ livers evaluated. Ferret and mongoose livers were also ranked in the lowest four species.Our results demonstrate that glucuronidation is a minor pathway for soy isoflavone metabolism in cats compared with most other species. PMID:26366946

  16. Soy isoflavone metabolism in cats compared with other species: urinary metabolite concentrations and glucuronidation by liver microsomes.

    PubMed

    Redmon, Joanna M; Shrestha, Binu; Cerundolo, Rosario; Court, Michael H

    2016-01-01

    1. Soybean is a common source of protein in many pet foods. Slow glucuronidation of soy-derived isoflavones in cats has been hypothesized to result in accumulation with adverse health consequences. Here, we evaluated species' differences in soy isoflavone glucuronidation using urine samples from cats and dogs fed a soy-based diet and liver microsomes from cats compared with microsomes from 12 other species. 2. Significant concentrations of conjugated (but not unconjugated) genistein, daidzein and glycitein, and the gut microbiome metabolites, dihydrogenistein and dihydrodaidzein, were found in cat and dog urine samples. Substantial amounts of conjugated equol were also found in cat urine but not in dog urine. 3. β-Glucuronidase treatment showed that all these compounds were significantly glucuronidated in dog urine while only daidzein (11%) and glycitein (37%) showed any glucuronidation in cat urine suggesting that alternate metabolic pathways including sulfation predominate in cats. 4. Glucuronidation rates of genistein, daidzein and equol by cat livers were consistently ranked within the lowest 3 out of 13 species' livers evaluated. Ferret and mongoose livers were also ranked in the lowest four species. 5. Our results demonstrate that glucuronidation is a minor pathway for soy isoflavone metabolism in cats compared with most other species.

  17. Hormonal monitoring of early pregnancy by a direct radioimmunoassay of steroid glucuronides in first morning urine

    SciTech Connect

    Mendizabal, A.F.; Quiroga, S.; Farinati, Z.; Lahoz, M.; Nagle, C.

    1984-11-01

    The usefulness of the direct 4-hour radioimmunoassay of estriol-16-glucuronide (E/sub 3/G) and pregnanediol-3-glucuronide (P/sub 2/G) in first morning urine (FMU) for establishing a prognosis of the early pregnancy outcome was evaluated in 106 patients that became pregnant. Microaliquots of FMU were serially assayed from day 3 of the conception cycle until day 80 of pregnancy. The E/sub 3/G and P/sub 2/G profiles of 19 pregnancies which terminated in spontaneous abortion with either a diagnosis of the blighted ovum syndrome (n = 11) or presumption of a corpus luteum/trophoblast failure (n = 8) have been compared with those of clinically normal pregnancies (n = 87). Normal pregnancies displayed typical patterns of E/sub 3/G and P/sub 2/G development, while variations were observed in abortive events that reflected changes of the fetoplacental unit.

  18. Synthesis and Evaluation of the Anti-Oxidant Capacity of Curcumin Glucuronides, the Major Curcumin Metabolites

    PubMed Central

    Choudhury, Ambar K.; Raja, Suganya; Mahapatra, Sanjata; Nagabhushanam, Kalyanam; Majeed, Muhammed

    2015-01-01

    Curcumin metabolites namely curcumin monoglucuronide and curcumin diglucuronide were synthesized using an alternative synthetic approach. The anti-oxidant potential of these curcumin glucuronides was compared with that of curcumin using DPPH scavenging method and Oxygen Radical Absorbance Capacity (ORAC) assay. The results show that curcumin monoglucuronide exhibits 10 fold less anti-oxidant activity (DPPH method) and the anti-oxidant capacity of curcumin diglucuronide is highly attenuated compared to the anti-oxidant activity of curcumin. PMID:26783957

  19. Reaction of primary and secondary amines to form carbamic acid glucuronides.

    PubMed

    Schaefer, William H

    2006-12-01

    Glucuronidation is an important mechanism used by mammalian systems to clear and eliminate both endogenous and foreign chemicals. Many functional groups are susceptible to conjugation with glucuronic acid, including hydroxyls, phenols, carboxyls, activated carbons, thiols, amines, and selenium. Primary and secondary amines can also react with carbon dioxide (CO(2)) via a reversible reaction to form a carbamic acid. The carbamic acid is also a substrate for glucuronidation and results in a stable carbamate glucuronide metabolite. The detection and characterization of these products has been facilitated greatly by the advent of soft ionization mass spectrometry techniques and high field NMR instrumentation. The formation of carbamate glucuronide metabolites has been described for numerous pharmaceuticals and they have been identified in all of the species commonly used in drug metabolism studies (rat, dog, mouse, rabbit, guinea pig, and human). There has been no obvious species specificity for their formation and no preference for 1 degrees or 2 degrees amines. Many biological reactions have also been described in the literature that involve the reaction of CO(2) with amino groups of biomolecules. For example, CO(2) generated from cellular respiration is expired in part through the reversible formation of a carbamate between CO(2) and the alpha-amino groups of the alpha- and beta-chains of hemoglobin. Also, carbamic acid products of several amines, such as beta-N-methylamino-L-alanine (BMAA), ethylenediamine, and L-cysteine have been implicated in toxicity. Studies suggested that a significant portion of amino-compounds in biological samples (that naturally contain CO(2)/bicarbonate) can be present as a carbamic acid.

  20. Preparation and separation of the glucuronide and sulfate conjugates of thyroxine and triiodothyronine

    SciTech Connect

    Hays, M.T.; Hsu, L.

    1987-01-01

    An enzymatic method for synthesis of labelled thyroxine glucuronide (T4G) and triiodothyronine glucuronide (T3G) from labelled thyroxine (T4) and triiodothyronine (T3) is presented. The synthetic glucuronides are completely digested by beta-glucuronidase, with recovery of the parent T4 or T3. They have distinctive elution patterns on HPLC and on Sephadex G25 chromatography, and can be clearly separated from T4 and T3 as well as from synthetic T4 sulfate (T4S) and T3 sulfate (T3S). On LH 20 chromatography, elution of T4G and T3G is intermediate between that of T4 and T3 and that of T4S and T3S. T3G can be well separated from other thyronines by HPLC alone, but T4G coelutes with rT3 on HPLC; these are then separated by adding a Sephadex G25 chromatography step. Biosynthetic /sup 131/I-T3G and /sup 125/I-T4G from the bile of a cat given /sup 131/I-T3 and /sup 125/I-T4 had similar HPLC chromatographic patterns to those of synthetic T3G and T4G. That the identified peaks from analysis of the bile were indeed T3G and T4G was confirmed by recovery of the parent T3 and T4 after beta-glucuronidase digestion.

  1. Extensive intestinal glucuronidation of raloxifene in vivo in pigs and impact for oral drug delivery.

    PubMed

    Thörn, Helena Anna; Yasin, Mohammed; Dickinson, Paul Alfred; Lennernäs, Hans

    2012-09-01

    In this study an advanced multisampling site pig model, with simultaneous venous blood sampling pre- and post liver, was applied to quantify the role of the intestine in relation to the liver in first-pass glucuronidation of raloxifene in vivo. The pharmacokinetic of raloxifene (a BCS/BDDCS class II compound) in humans is characterized by extensive metabolism (>90%) and the major metabolite is the 4'-β-glucuronide (R-4-G). Following intra-jejunal (i.j.) single dose administration in pigs raloxifene was metabolized in the gut (E(G)) during first-pass to more than 70% and a high concentration (AUC(0-6 h) ratio R-4-G/raloxifene >100) of R-4-G was reached in the portal vein. The hepatic extraction (E(H)) of raloxifene was ~50% and as in humans the bioavailability become low (~7%) in pigs. Interestingly the E(H) of raloxifene and R-4-G was time-dependent after i.j. administration. It is clear that the gut was the dominating organ in first-pass extraction of raloxifene in vivo in pigs. The quantification in this study support earlier human data and emphasize that intestinal glucuronidation should be considered early in the pharmaceutical development.

  2. Regioselective Sulfation and Glucuronidation of Phenolics: Insights into the Structural Basis of Conjugation

    PubMed Central

    Wu, Baojian; Basu, Sumit; Meng, Shengnan; Wang, Xiaoqiang; Zhang, Shuxing; Hu, Ming

    2012-01-01

    The phase II metabolism sulfation and glucuronidation, mediated by sulfotransferases (SULTs) and UDP-glucuronosyltransferases (UGTs) respectively, are significant metabolic pathways for numerous endo- and xenobiotics. Understanding of SULT/UGT substrate specificity (including regioselectivity (i.e., position preference)) is of great importance in predicting contribution of sulfation/glucuronidation to drug and metabolite disposition in vivo. This review summarizes regioselective sulfation and glucuronidation of phenolic compounds with multiple hydroxyl (OH) groups as the potential conjugation sites. The strict regioselective patterns were highlighted for several SULT and UGT isoforms towards flavonoids, a large class of natural polyphenols. To seek for a molecular-level explanation, the enzyme structures (i.e., SULT crystal structures and homology-based UGT structure models) combined with molecular docking was employed. In particular, the structural bases for regioselective metabolism of flavonoids by SULT1A3 and UGT1A1 were discussed. It was concluded that the regioselective nature of these phase II enzymes was determined by the size and shape of binding pocket. While the molecular structures of the enzymes can be used to explain regioselective metabolism regarding the binding property, predicting the turnover at different positions remains a particularly difficult task. PMID:21933112

  3. Immunohistochemical localization and quantification of the 3-(cystein-S-yl)-acetaminophen protein adduct in acetaminophen hepatotoxicity.

    PubMed

    Roberts, D W; Bucci, T J; Benson, R W; Warbritton, A R; McRae, T A; Pumford, N R; Hinson, J A

    1991-02-01

    Acetaminophen overdose causes severe hepatotoxicity in humans and laboratory animals, presumably by metabolism to N-acetyl-p-benzoquinone imine: and binding to cysteine groups as 3-(cystein-S-yl)acetaminophen-protein adduct. Antiserum specific for the adduct was used immunohistochemically to demonstrate the formation, distribution, and concentration of this specific adduct in livers of treated mice and was correlated with cell injury as a function of dose and time. Within the liver lobule, immunohistochemically demonstrable adduct occurred in a temporally progressive, central-to-peripheral pattern. There was concordance between immunohistochemical staining and quantification of the adduct in hepatic 10,000g supernate, using a quantitative particle concentration fluorescence immunoassay. Findings include: 1) immunochemically detectable adduct before the appearance of centrilobular necrosis, 2) distinctive lobular zones of adduct localization with subsequent depletion during the progression of toxicity, 3) drug-protein binding in hepatocytes at subhepatotoxic doses and before depletion of total hepatic glutathione, 4) immunohistochemical evidence of drug binding in the nucleus, and 5) adduct in metabolically active and dividing hepatocytes and in macrophagelike cells in the regenerating liver.

  4. Novel acidic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor with reduced acyl glucuronide liability: the discovery of 4-[4-(2-adamantylcarbamoyl)-5-tert-butyl-pyrazol-1-yl]benzoic acid (AZD8329).

    PubMed

    Scott, James S; deSchoolmeester, Joanne; Kilgour, Elaine; Mayers, Rachel M; Packer, Martin J; Hargreaves, David; Gerhardt, Stefan; Ogg, Derek J; Rees, Amanda; Selmi, Nidhal; Stocker, Andrew; Swales, John G; Whittamore, Paul R O

    2012-11-26

    Inhibition of 11β-HSD1 is viewed as a potential target for the treatment of obesity and other elements of the metabolic syndrome. We report here the optimization of a carboxylic acid class of inhibitors from AZD4017 (1) to the development candidate AZD8329 (27). A structural change from pyridine to pyrazole together with structural optimization led to an improved technical profile in terms of both solubility and pharmacokinetics. The extent of acyl glucuronidation was reduced through structural optimization of both the carboxylic acid and amide substituents, coupled with a reduction in lipophilicity leading to an overall increase in metabolic stability.

  5. Pharmacokinetics of epidurally administered nicomorphine with its metabolites and glucuronide conjugates in patients undergoing pulmonary surgery during combined epidural local anaesthetic block and general anaesthesia.

    PubMed

    Koopman-Kimenai, P M; Vree, T B; Booij, L H; Hasenbos, M A

    1995-08-01

    After epidural administration of 15 mg 3, 6-dinicotinoylmorphine (nicomorphine) in 10 patients undergoing pulmonary surgery, the parent compound was quickly metabolized into the metabolites 6-mononicotinoylmorphine and morphine. The mean apparent half-lives (+/- SD) of elimination were 10 min (0.165 h +/- 0.053 h) for 3,6-dinicotinoylmorphine and 1.77 h +/- 1.23 h for 6-mononicotinoylmorphine. Morphine is subsequently metabolized into morphine-3-glucuronide and morphine-6-glucuronide. The apparent half-lives of morphine, morphine-3-glucuronide, and morphine-6-glucuronide are similar: 3.63 h +/- 1.63 h, 4.10 h +/- 0.57 h, and 4.20 h +/- 1.64 h respectively. The possible glucuronide conjugate of 6-mononicotinoylmorphine was not detected. The prodrug 3,6-dinicotinoylmorphine was biotransformed into three active compounds: 6-mononicotinoylmorphine, morphine, and morphine-6-glucuronide.

  6. BLT1 signalling protects the liver against acetaminophen hepatotoxicity by preventing excessive accumulation of hepatic neutrophils

    PubMed Central

    Kojo, Ken; Ito, Yoshiya; Eshima, Koji; Nishizawa, Nobuyuki; Ohkubo, Hirotoki; Yokomizo, Takehiko; Shimizu, Takao; Watanabe, Masahiko; Majima, Masataka

    2016-01-01

    Leukotriene B4 (LTB4) is a potent chemoattractant for neutrophils. Signalling of LTB4 receptor type 1 (BLT1) has pro-inflammatory functions through neutrophil recruitment. In this study, we investigated whether BLT1 signalling plays a role in acetaminophen (APAP)-induced liver injury by affecting inflammatory responses including the accumulation of hepatic neutrophils. BLT1-knockout (BLT1−/−) mice and their wild-type (WT) counterparts were subjected to a single APAP overdose (300 mg/kg), and various parameters compared within 24 h after treatment. Compared with WT mice, BLT1−/− mice exhibited exacerbation of APAP-induced liver injury as evidenced by enhancement of alanine aminotransferase level, necrotic area, hepatic neutrophil accumulation, and expression of cytokines and chemokines. WT mice co-treated with APAP and ONO-0457, a specific antagonist for BLT1, displayed amplification of the injury, and similar results to those observed in BLT1−/− mice. Hepatic neutrophils in BLT1−/− mice during APAP hepatotoxicity showed increases in the production of reactive oxygen species and matrix metalloproteinase-9. Administration of isolated BLT1-deficient neutrophils into WT mice aggravated the liver injury elicited by APAP. These results demonstrate that BLT1 signalling dampens the progression of APAP hepatotoxicity through inhibiting an excessive accumulation of activated neutrophils. The development of a specific agonist for BLT1 could be useful for the prevention of APAP hepatotoxicity. PMID:27404729

  7. Antioxidant and Hepatoprotective Efficiency of Selenium Nanoparticles Against Acetaminophen-Induced Hepatic Damage.

    PubMed

    Amin, Kamal Adel; Hashem, Khalid Shaban; Alshehri, Fawziah Saleh; Awad, Said T; Hassan, Mohammed S

    2017-01-01

    Overdoses of acetaminophen (APAP), a famous and widely used drug, may have hepatotoxic effects. Nanoscience is a novel scientific discipline that provides specific tools for medical science problems including using nano trace elements in hepatic diseases. Our study aimed to assess the hepatoprotective role of selenium nanoparticles (Nano-Se) against APAP-induced hepatic injury. Twenty-four male rats were classified into three equal groups: a control group that received 0.9 % NaCl, an APAP-treated group (oral administration), and a group treated with Nano-Se (10-20 nm, intraperitoneal (i.p.) injection) and APAP (oral administration). APAP overdose induced significant elevations in liver function biomarkers, hepatic lipid peroxidation, hepatic catalase, and superoxide dismutase (SOD), decreased the reduced glutathione (GSH) content and glutathione reductase (GR) activity, and stimulated significant DNA damage in hepatocytes, compared to control rats. Nano-Se administration improved the hepatic antioxidant protection mechanism and decreased cellular sensitivity to DNA fragmentation. Nano-Se exhibits a protective effect against APAP-induced hepatotoxicity through improved liver function and oxidative stress mediated by catalase, SOD, and GSH and decreases hepatic DNA fragmentation, a hepatic biomarker of cell death. Nano-Se could be a novel hepatoprotective strategy to inhibit oxidative stress.

  8. Adenosine 5′-monophosphate blocks acetaminophen toxicity by increasing ubiquitination-mediated ASK1 degradation

    PubMed Central

    Sun, Qi; Xu, Xi; Kong, Yi; Zhang, Jianfa

    2017-01-01

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced liver failure in the world. Hepatic c-jun NH2-terminal protein kinase (JNK) activation is thought to be a consequence of oxidative stress produced during APAP metabolism. Activation of JNK signals causes hepatocellular damage with necrotic and apoptotic cell death. Here we found that APAP caused a feedback increase in plasma adenosine 5′-monophsphate (5′-AMP). We demonstrated that co-administration of APAP and 5′-AMP significantly ameliorated APAP-induced hepatotoxicity in mice, without influences on APAP metabolism and its analgesic function. The mechanism of protection by 5′-AMP was through inhibiting APAP-induced activation of JNK, and attenuating downstream c-jun and c-fos gene expression. This was triggered by attenuating apoptosis signal-regulated kinase 1(ASK1) methylation and increasing ubiquitination-mediated ASK1 protein degradation. Our findings indicate that replacing the current APAP with a safe and functional APAP/5′-AMP formulation could prevent APAP-induced hepatotoxicity. PMID:28031524

  9. The relative protein abundance of UGT1A alternative splice variants as a key determinant of glucuronidation activity in vitro.

    PubMed

    Rouleau, Mélanie; Roberge, Joannie; Falardeau, Sarah-Ann; Villeneuve, Lyne; Guillemette, Chantal

    2013-04-01

    Alternative splicing (AS) is one of the most significant components of the functional complexity of human UDP-glucuronosyltransferase enzymes (UGTs), particularly for the UGT1A gene, which represents one of the best examples of a drug-metabolizing gene regulated by AS. Shorter UGT1A isoforms [isoform 2 (i2)] are deficient in glucuronic acid transferase activity but function as negative regulators of enzyme activity through protein-protein interaction. Their abundance, relative to active UGT1A enzymes, is expected to be a determinant of the global transferase activity of cells and tissues. Here we tested whether i2-mediated inhibition increases with greater abundance of the i2 protein relative to the isoform 1 (i1) enzyme, using the extrahepatic UGT1A7 as a model and a series of 23 human embryonic kidney 293 clonal cell lines expressing variable contents of i1 and i2 proteins. Upon normalization for i1, a significant reduction of 7-ethyl-10-hydroxycamptothecin glucuronide formation was observed for i1+i2 clones (mean of 53%) compared with the reference i1 cell line. In these clones, the i2 protein content varied greatly (38-263% relative to i1) and revealed two groups: 17 clones with i2 < i1 (60% ± 3%) and 6 clones with i2 ≥ i1 (153% ± 24%). The inhibition induced by i2 was more substantial for clones displaying i2 ≥ i1 (74.5%; P = 0.001) compared with those with i2 < i1 (45.5%). Coimmunoprecipitation supports a more substantial i1-i2 complex formation when i2 exceeds i1. We conclude that the relative abundance of regulatory i2 proteins has the potential to drastically alter the local drug metabolism in the cells, particularly when i2 surpasses the protein content of i1.

  10. A zeolite modified carbon paste electrode as useful sensor for voltammetric determination of acetaminophen.

    PubMed

    Ahmadpour-Mobarakeh, Leila; Nezamzadeh-Ejhieh, Alireza

    2015-04-01

    The voltammetric behavior of a carbon paste electrode modified with Co(II)-exchanged zeolite A (Co(II)-A/ZMCPE) for determination of acetaminophen was studied. The proposed electrode showed a diffusion controlled reaction with the electron transfer rate constant (Ks) of 0.44s(-1) and charge transfer coefficient of 0.73 in the absence of acetaminophen. A linear voltammetric response was obtained in the range of 0.1 to 190μmolL(-1) of acetaminophen [r(2)=0.9979, r=0.9989 (n=10)] with a detection limit of 0.04μmolL(-1). The method was successfully applied to the analysis of acetaminophen in some drugs.

  11. Drugs in the Chemistry Laboratory: The Conversion of Acetaminophen into Phenacetin.

    ERIC Educational Resources Information Center

    Volker, Eugene J.; And Others

    1979-01-01

    Describes an experiment in which acetaminophen is converted into phenacetin, that has been used at Shepherd College in an introductory chemistry course for nurses and in the organic chemistry laboratory. (BT)

  12. LC-MS/MS method development for quantitative analysis of acetaminophen uptake by the aquatic fungus Mucor hiemalis.

    PubMed

    Esterhuizen-Londt, Maranda; Schwartz, Katrin; Balsano, Evelyn; Kühn, Sandra; Pflugmacher, Stephan

    2016-06-01

    Acetaminophen is a pharmaceutical, frequently found in surface water as a contaminant. Bioremediation, in particular, mycoremediation of acetaminophen is a method to remove this compound from waters. Owing to the lack of quantitative analytical method for acetaminophen in aquatic organisms, the present study aimed to develop a method for the determination of acetaminophen using LC-MS/MS in the aquatic fungus Mucor hiemalis. The method was then applied to evaluate the uptake of acetaminophen by M. hiemalis, cultured in pellet morphology. The method was robust, sensitive and reproducible with a lower limit of quantification of 5 pg acetaminophen on column. It was found that M. hiemalis internalize the pharmaceutical, and bioaccumulate it with time. Therefore, M. hiemalis was deemed a suitable candidate for further studies to elucidate its pharmaceutical tolerance and the longevity in mycoremediation applications.

  13. Acetaminophen intake and risk of asthma, hay fever and eczema in early adolescence.

    PubMed

    Vlaski, Emilija; Stavric, Katerina; Isjanovska, Rozalinda; Seckova, Lidija; Kimovska, Milica

    2007-09-01

    A positive association between acetaminophen intake and allergic diseases has recently been reported in developed countries with impaired oxidant/antioxidant balance and promotion of atopy as proposed underlying mechanisms. The aim of the study was to explore the relationship between acetaminophen intake and asthma, hay fever, and eczema in The Republic of Macedonia as a country with acetaminophen intake not physician-controlled, high passive smoke exposure and dietary antioxidant intake, and moderately low prevalence of allergic diseases. Self-reported data obtained through the standardized International Study of Asthma and Allergies in Childhood Phase Three written questionnaires of 3026 adolescents aged 13/14 years from randomly selected schools in Skopje, the capital of Macedonia, were used. The frequency of current acetaminophen intake--both unadjusted and adjusted for confounding factors--was correlated to current and ever-diagnosed asthma, hay fever and eczema by odds ratios (OR, 95% CI) in binary logistic regression. Use of acetaminophen at least once monthly increased the risk of current wheeze (adjusted OR 2.04, 1.31-3.20 p = 0.002), asthma 'ever' (adjusted OR 2.77, 1.06-7.26 p=0.039), current allergic rhinoconjunctivitis (adjusted OR 2.95, 1.79-4.88 p=0.000) and hay fever 'ever' (adjusted OR 2.25, 1.36-3.70 p=0.002). A significant association between frequent acetaminophen intake and atopic eczema and also between infrequent acetaminophen intake and investigated allergic diseases was not established. The findings suggest an increased risk of asthma and hay fever, but not atopic eczema associated with frequent acetaminophen use in a developing country.

  14. Liuweiwuling tablets protect against acetaminophen hepatotoxicity: What is the protective mechanism?

    PubMed Central

    Du, Kuo; Jaeschke, Hartmut

    2016-01-01

    Study of the effects of natural products, including traditional Chinese Medicines, on acetaminophen hepatotoxicity has gained considerable popularity in recent years, and some of them showed positive results and even promising therapeutic potentials. A recent report suggested that Liuweiwuling tablets protect against acetaminophen hepatotoxicity and promote liver regeneration in a rodent model through alleviating the inflammatory response. However, several concerns exist regarding the limitations of the experimental design and interpretation of the data presented in this manuscript. PMID:27004010

  15. Acetaminophen absorption kinetics in altered gastric emptying: establishing a relevant pharmacokinetic surrogate using published data.

    PubMed

    Srinivas, Nuggehally R

    2015-06-01

    Acetaminophen has been used as a tool for clinical and nonclinical experimental designs that evaluate gastric emptying because acetaminophen is not absorbed in stomach but efficiently absorbed from the small intestine. Published pharmacokinetic data of acetaminophen in subjects with normal gastric emptying vs. impaired gastric emptying (i.e., morphine treatment) were evaluated to select a key surrogate. Using Caverage (average concentration), computed from the exposure within the first hour, individual rank distribution was plotted across different studies. Caverage was highly correlated with Cmax (maximum concentration) in subjects with normal gastric emptying (R(2) = .7532) but not in those where gastric emptying was impaired (R(2) = .0213). The 50th percentile value of the distribution pattern of 1/Caverage in acetaminophen+morphine-treated group (coincided with the first shift in the slope) was considered as the cutoff point to figure out the impaired gastric emptying. The individual rank distribution plots for 1/Caverage across different studies supported similar trends in subjects with normal gastric emptying but showed a distinct distribution pattern in the cohort of impaired gastric emptying. Caverage, calculated within the first hour of dosing of acetaminophen (average concentration at 0-1 hour, C0-1havg), can be used as a key surrogate to distinguish the effects of gastric emptying on the absorption of acetaminophen. A 4 μg/mL C0-1havg of acetaminophen (dose: 1.5 g) may be used as cutoff point in future clinical investigations of acetaminophen to clarify the role of gastric emptying.

  16. Acetaminophen use and risk of myocardial infarction and stroke in a hypertensive cohort.

    PubMed

    Fulton, Rachael L; Walters, Matthew R; Morton, Ross; Touyz, Rhian M; Dominiczak, Anna F; Morrison, David S; Padmanabhan, Sandosh; Meredith, Peter A; McInnes, Gordon T; Dawson, Jesse

    2015-05-01

    Recent data suggest that self-reported acetaminophen use is associated with increased risk of cardiovascular events and that acetaminophen causes a modest blood pressure rise. There are no randomized trials or studies using verified prescription data of this relationship. We aimed to assess the relationship between verified acetaminophen prescription data and risk of myocardial infarction or stroke in patients with hypertension. We performed a retrospective data analysis using information contained within the UK Clinical Research Practice Datalink. Multivariable Cox proportional hazard models were used to estimate hazard ratios for myocardial infarction (primary end point), stroke, and any cardiovascular event (secondary end points) associated with acetaminophen use during a 10-year period. Acetaminophen exposure was a time-dependent variable. A propensity-matched design was also used to reduce potential for confounding. We included 24,496 hypertensive individuals aged ≥ 65 years. Of these, 10,878 were acetaminophen-exposed and 13,618 were not. There was no relationship between risk of myocardial infarction, stroke, or any cardiovascular event and acetaminophen exposure on adjusted analysis (hazard ratio, 0.98; 95% confidence interval, 0.76-1.27; hazard ratio, 1.09; 95% confidence interval, 0.86-1.38; and hazard ratio, 1.17; 95% confidence interval, 0.99-1.37; respectively). Results in the propensity-matched sample (n=4000 per group) and when men and women were analyzed separately were similar. High-frequency users (defined as receiving a prescription for >75% of months) were also not at increased risk. After allowance for potentially confounding variables, the use of acetaminophen was not associated with an increased risk of myocardial infarction or stroke in a large cohort of hypertensive patients.

  17. Diabetic KK-A(y) mice are highly susceptible to oxidative hepatocellular damage induced by acetaminophen.

    PubMed

    Kon, Kazuyoshi; Ikejima, Kenichi; Okumura, Kyoko; Arai, Kumiko; Aoyama, Tomonori; Watanabe, Sumio

    2010-08-01

    Despite pathophysiological similarities to alcoholic liver disease, susceptibility to acetaminophen hepatotoxicity in metabolic syndrome-related nonalcoholic steatohepatitis (NASH) has not been well elucidated. In this study, therefore, we investigated acetaminophen-induced liver injury in KK-A(y) mice, an animal model of metabolic syndrome. Twelve-week-old male KK-A(y) and C57Bl/6 mice were injected intraperitoneally with 300 or 600 mg/kg acetaminophen, and euthanized 6 h later. Liver histology was assessed, and hepatic expression of 4-hydroxy-2-nonenal was detected by immunohistochemistry. Levels of reduced glutathione were determined spectrophotometrically. Phosphorylation of c-Jun NH(2)-terminal kinase (JNK) was analyzed by Western blotting. Hepatocytes were isolated from both strains by collagenase perfusion, and cell death and oxidative stress were measured fluorometrically by use of propidium iodide and 5-(and-6)-chloromethyl-2'7'-dichloro-dihydrofluorescein diacetate acetyl ester, respectively. Acetaminophen induced more severe necrosis and apoptosis of hepatocytes in KK-A(y) mice than in C57Bl/6 mice and significantly increased serum alanine aminotransferase levels in KK-A(y) mice. Acetaminophen-induction of 4-hydroxy-2-nonenal in the liver was potentiated, whereas the levels of reduced glutathione in liver were lower in KK-A(y) mice. Acetaminophen-induced phosphorylation of JNK in the liver was also enhanced in KK-A(y) mice. Exposure to 20 microM tert-butyl hydroperoxide did not kill hepatocytes isolated from C57Bl/6 mice but induced cell death and higher oxidative stress in hepatocytes from KK-A(y) mice. These results demonstrated that acetaminophen toxicity is increased in diabetic KK-A(y) mice mainly due to enhanced oxidative stress in hepatocytes, suggesting that metabolic syndrome-related steatohepatitis is an exacerbating factor for acetaminophen-induced liver injury.

  18. Blockade of Notch signaling promotes acetaminophen-induced liver injury.

    PubMed

    Jiang, Longfeng; Ke, Michael; Yue, Shi; Xiao, Wen; Yan, Youde; Deng, Xiaozhao; Ying, Qi-Long; Li, Jun; Ke, Bibo

    2017-03-13

    Liver injury after experimental acetaminophen treatment is mediated both by direct hepatocyte injury through a P450-generated toxic metabolite and indirectly by activated liver Kupffer cells and neutrophils. This study was designed to investigate the role of Notch signaling in the regulation of innate immune responses in acetaminophen (APAP)-induced liver injury. Using a mouse model of APAP-induced liver injury, wild-type (WT) and toll-like receptor 4 knockout (TLR4 KO) mice were injected intraperitoneally with APAP or PBS. Some animals were injected with γ-secretase inhibitor DAPT or DMSO vehicle. For the in vitro study, bone marrow-derived macrophages (BMMs) were transfected with Notch1 siRNA, TLR4 siRNA, and non-specific (NS) siRNA and stimulated with LPS. Indeed, paracetamol/acetaminophen-induced liver damage was worse after Notch blockade with DAPT in wild-type mice, which was accompanied by significantly increased ALT levels, diminished hairy and enhancer of split-1 (Hes1), and phosphorylated Stat3 and Akt but enhanced high mobility group box 1 (HMGB1), TLR4, NF-κB, and NLRP3 activation after APAP challenge. Mice receiving DAPT increased macrophage and neutrophil accumulation and hepatocellular apoptosis. However, TLR4 KO mice that received DAPT reduced APAP-induced liver damage and NF-κB, NLRP3, and cleaved caspase-1 activation. BMMs transfected with Notch1 siRNA reduced Hes1 and phosphorylated Stat3 and Akt but augmented HMGB1, TLR4, NF-κB, and NLRP3. Furthermore, TLR4 siRNA knockdown resulted in decreased NF-κB and NLRP3 and cleaved caspase-1 and IL-1β levels following LPS stimulation. These results demonstrate that Notch signaling regulates innate NLRP3 inflammasome activation through regulation of HMGB1/TLR4/NF-κB activation in APAP-induced liver injury. Our novel findings underscore the critical role of the Notch1-Hes1 signaling cascade in the regulation of innate immunity in APAP-triggered liver inflammation. This might imply a novel therapeutic

  19. Hepatoprotective effect of coenzyme Q10 in rats with acetaminophen toxicity.

    PubMed

    Fouad, Amr A; Jresat, Iyad

    2012-03-01

    The potential protective effect of coenzyme Q10 against acute liver injury induced by a single dose of acetaminophen (700 mg/kg, p.o.) was investigated in rats. Coenzyme Q10 treatment was given as two i.p. injections, 10 mg/kg each, at 1 and 12 h following acetaminophen administration. Coenzyme Q10 significantly reduced the levels of serum aminotransferases, suppressed lipid peroxidation, prevented the decreases of reduced glutathione and catalase activity, decreased the elevations of tumor necrosis factor-α and nitric oxide as well as attenuating the reductions of selenium and zinc ions in liver tissue resulting from acetaminophen administration. Histopathological liver tissue damage mediated by acetaminophen was ameliorated by coenzyme Q10. Immunohistochemical analysis revealed that coenzyme Q10 significantly decreased the acetaminophen-induced overexpression of inducible nitric oxide synthase, nuclear factor-κB, caspase-3 and p53 in liver tissue. It was concluded that coenzyme Q10 protects rat liver against acute acetaminophen hepatotoxicity, most probably through its antioxidant, anti-inflammatory and antiapoptotic effects.

  20. Hepatoprotective effects of Arctium lappa on carbon tetrachloride- and acetaminophen-induced liver damage.

    PubMed

    Lin, S C; Chung, T C; Lin, C C; Ueng, T H; Lin, Y H; Lin, S Y; Wang, L Y

    2000-01-01

    The root of Arctium lappa Linne (A. lappa) (Compositae), a perennial herb, has been cultivated for a long time as a popular vegetable. In order to investigate the hepatoprotective effects of A. lappa, male ICR mice were injected with carbon tetrachloride (CCl4, 32 microl/kg, i.p.) or acetaminophen (600 mg/kg, i.p.). A. lappa suppressed the SGOT and SGPT elevations induced by CCl4 or acetaminophen in a dose-dependent manner and alleviated the severity of liver damage based on histopathological observations. In an attempt to elucidate the possible mechanism(s) of this hepatoprotective effect, glutathione (GSH), cytochrome P-450 (P-450) and malondialdehyde (MDA) contents were studied. A. lappa reversed the decrease in GSH and P-450 induced by CCl4 and acetaminophen. It was also found that A. lappa decreased the malondialdehyde (MDA) content in CCl4 or acetaminophen-intoxicated mice. From these results, it was suggested that A. lappa could protect the liver cells from CCl4 or acetaminophen-induced liver damages, perhaps by its antioxidative effect on hepatocytes, hence eliminating the deleterious effects of toxic metabolites from CCl4 or acetaminophen.

  1. From painkiller to empathy killer: acetaminophen (paracetamol) reduces empathy for pain.

    PubMed

    Mischkowski, Dominik; Crocker, Jennifer; Way, Baldwin M

    2016-09-01

    Simulation theories of empathy hypothesize that empathizing with others' pain shares some common psychological computations with the processing of one's own pain. Support for this perspective has largely relied on functional neuroimaging evidence of an overlap between activations during the experience of physical pain and empathy for other people's pain. Here, we extend the functional overlap perspective to the neurochemical level and test whether a common physical painkiller, acetaminophen (paracetamol), can reduce empathy for another's pain. In two double-blind placebo-controlled experiments, participants rated perceived pain, personal distress and empathic concern in response to reading scenarios about another's physical or social pain, witnessing ostracism in the lab, or visualizing another study participant receiving painful noise blasts. As hypothesized, acetaminophen reduced empathy in response to others' pain. Acetaminophen also reduced the unpleasantness of noise blasts delivered to the participant, which mediated acetaminophen's effects on empathy. Together, these findings suggest that the physical painkiller acetaminophen reduces empathy for pain and provide a new perspective on the neurochemical bases of empathy. Because empathy regulates prosocial and antisocial behavior, these drug-induced reductions in empathy raise concerns about the broader social side effects of acetaminophen, which is taken by almost a quarter of adults in the United States each week.

  2. Impact of Educational Levels and Health Literacy on Community Acetaminophen Knowledge.

    PubMed

    Ip, Eric J; Tang, Terrill T-L; Cheng, Vincent; Yu, Junhua; Cheongsiatmoy, Derren S

    2015-12-01

    Patient understanding of acetaminophen is important for its safe and appropriate self-use. A cross-sectional survey was conducted in the San Francisco Bay Area to determine the impact of educational level, patient health literacy score, and other demographic characteristics on acetaminophen knowledge. A 17-item, in-person, paper-and-pen questionnaire containing questions about demographics and acetaminophen knowledge was administered to 311 adults outside 5 local grocery stores in varying socioeconomic communities. Knowledge assessed was whether Tylenol-McNeil contains acetaminophen, maximum daily dose, and primary organ affected by toxicity. Participant health literacy was evaluated using the Rapid Estimate of Adult Literacy in Medicine-Short Form (REALM-SF) test. Of the 300 who successfully completed the study, only 3.8% of all subjects were able to answer all 3 acetaminophen knowledge questions correctly regardless of educational level or health literacy score. This reaffirms that a lack of appropriate acetaminophen knowledge remains present in the general population, and further efforts to educate patients will be needed to prevent adverse events.

  3. Acetaminophen Use for Fever in Children Associated with Autism Spectrum Disorder

    PubMed Central

    Schultz, Stephen T; Gould, Georgianna G

    2016-01-01

    Autism Spectrum Disorder (ASD) is characterized by persistent deficits in social communication and restrictive behavior, interests, and activities. Our previous case-control study showed that use of acetaminophen at age 12–18 months is associated with increased likelihood for ASD (OR 8.37, 95% CI 2.08–33.7). In this study, we again show that acetaminophen use is associated with ASD (p = 0.013). Because these children are older than in our first study, the association is reversed; fewer children with ASD vs. non-ASD children use acetaminophen as a “first choice” compared to “never use” (OR 0.165, 95% CI 0.045, 0.599). We found significantly more children with ASD vs. non- ASD children change to the use of ibuprofen when acetaminophen is not effective at reducing fever (p = 0.033) and theorize this change in use is due to endocannabinoid system dysfunction. We also found that children with ASD vs. non-ASD children are significantly more likely to show an increase in sociability when they have a fever (p = 0.037) and theorize that this increase is due to anandamide activation of the endocannabinoid system in ASD children with low endocannabinoid tone from early acetaminophen use. In light of this we recommend that acetaminophen use be reviewed for safety in children. PMID:27695658

  4. The effect of acetaminophen nanoparticles on liver toxicity in a rat model.

    PubMed

    Biazar, Esmaeil; Rezayat, S Mahdi; Montazeri, Naser; Pourshamsian, Khalil; Zeinali, Reza; Asefnejad, Azadeh; Rahimi, Mehdi; Zadehzare, Mohammadmajid; Mahmoudi, Mehran; Mazinani, Rohollah; Ziaei, Mehdi

    2010-04-07

    Acetaminophen, a pain-reliever, is one of the most widely used medications in the world. Acetaminophen with normal dosage is considered a nontoxic drug for therapeutic applications, but when taken at overdose levels it produces liver damage in human and various animal species. By a high energy mechanically activated method, we produced acetaminophen in a nanometer crystalline size (24 nm). Forty-eight hours after injection of crystalline particles with normal and reduced size of our drug, the effect of liver toxicity was compared by determination of liver transferase enzymes such as alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase (ALT). These enzymes were examined by routine colorimetric methods using commercial kits and pathologic investigations. Statistical analysis and pathological figures indicated that ALT delivery and toxicity in reduced size acetaminophen was significantly reduced when compared with normal size acetaminophen. Pathology figures exhibited reduced necrosis effects, especially the confluent necrosis, in the central part of the lobule in the reduced size acetaminophen samples when compared with the normal samples.

  5. Urine ethyl glucuronide and ethyl sulphate using liquid chromatography-tandem mass spectrometry in a routine clinical laboratory.

    PubMed

    Armer, Jane M; Allcock, Rebecca L

    2017-01-01

    Background Detection of alcohol consumption in clients undergoing treatment for alcohol dependence can be difficult. The ethanol metabolites ethyl glucuronide and ethyl sulphate are detectable for longer in urine than either breath ethanol or urine ethanol. Our aim was to develop a liquid chromatography-tandem mass spectrometry method for urine ethyl glucuronide and ethyl sulphate for use in a routine clinical laboratory and define clinical cut-offs in a large population who had not consumed alcohol for at least two weeks. Methods Urine samples were diluted in 0.05% formic acid in HPLC grade water and then directly injected onto a Waters Acquity ultra high performance liquid chromatography coupled to a Waters TQ Detector. Eighty participants were recruited who had not consumed alcohol for at least two weeks to define cut-offs for urine ethyl glucuronide and ethyl sulphate. Samples and alcohol diaries were also collected from 12 alcohol-dependent clients attending a treatment programme. Results The assay was validated with a lower limit of quantitation of 0.20 mg/L for ethyl glucuronide and 0.04 mg/L for ethyl sulphate. Accuracy, precision, linearity and recovery were acceptable. Cut-offs were established for ethyl glucuronide, ethyl sulphate and ethyl sulphate/creatinine ratio (≤0.26 mg/L, ≤0.22 mg/L and ≤0.033 mg/mmol, respectively) in a non-drinking population. The validated cut-offs correctly identified clients in alcohol treatment who were continuing to drink alcohol. Conclusions A simple liquid chromatography-tandem mass spectrometry method for urine ethyl glucuronide and ethyl sulphate has been validated and cut-offs defined using 80 participants who had not consumed alcohol for at least two weeks. This is the largest study to date to define cut-offs for ethyl glucuronide, ethyl sulphate and ethyl sulphate/creatinine ratio.

  6. Simultaneous Quantification of Free and Glucuronidated Cannabinoids in Human Urine by Liquid Chromatography-Tandem Mass Spectrometry

    PubMed Central

    Scheidweiler, Karl B.; Desrosiers, Nathalie A.; Huestis, Marilyn A.

    2012-01-01

    Background Cannabis is the most commonly abused drug of abuse and is commonly quantified during urine drug testing. We conducted a controlled drug administration studies investigating efficacy of urinary cannabinoid glucuronide metabolites for documenting recency of cannabis intake and for determining stability of urinary cannabinoids. Methods A liquid chromatography tandem mass spectrometry method was developed and validated quantifying Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol, cannabinol, THC-glucuronide and THCCOOH-glucuronide in 0.5 ml human urine via supported-liquid extraction. Chromatography was performed on an Ultra Biphenyl column with a gradient of 10 mmol/l ammonium acetate, pH 6.15 and 15% methanol in acetonitrile at 0. 4ml/min. Analytes were monitored by positive and negative mode electrospray ionization and multiple reaction monitoring mass spectrometry. Results Linear ranges were 0.5–50 ng/ml for THC-glucuronide, 1–100 ng/ml for THCCOOH, 11-OH-THC and cannabidiol, 2–100 ng/ml for THC and cannabinol, and 5–500 ng/ml for THCCOOH-glucuronide (R2>0.99). Mean extraction efficiencies were 34–73% with analytical recovery (bias) 80.5–118.0% and total imprecision 3.0–10.2% coefficient of variation. Conclusion This method simultaneously quantifies urinary cannabinoids and phase II glucuronide metabolites, and enables evaluation of urinary cannabinoid glucuronides for documenting recency of cannabis intake and cannabinoid stability. The assay is applicable for routine urine cannabinoid testing. PMID:22771478

  7. Quaternary ammonium-linked glucuronidation of tamoxifen by human liver microsomes and UDP-glucuronosyltransferase 1A4.

    PubMed

    Kaku, Teppei; Ogura, Kenichiro; Nishiyama, Takahito; Ohnuma, Tomokazu; Muro, Kei; Hiratsuka, Akira

    2004-06-01

    Tamoxifen (TAM), a nonsteroidal antiestrogen, is the most widely used drug for chemotherapy of hormone-dependent breast cancer in women. In the present study, we found a new potential metabolic pathway of TAM via N-linked glucuronic acid conjugation for excretion in humans. TAM N(+)-glucuronide was isolated from a reaction mixture consisting of TAM and human liver microsomes fortified with UDP-glucuronic acid (UDPGA) and identified with a synthetic specimen by high-performance liquid chromatography-electrospray ionization-mass spectrometry. However, no TAM-glucuronidating activity was detected in microsomes from rat, mouse, monkey, dog, and guinea pig livers. A strong correlation (r(2) =0.92 ) was observed between N-glucuronidating activities toward TAM and trifluoperazine, a probe substrate for human UDP-glucuronosyltransferase (UGT) 1A4, in human liver microsomes from eight donors (five females, three males). However, no correlation ( (r(2) =0.02 )) was observed in the activities between 7-hydroxy-4-(trifluoromethyl)coumarin and TAM. Only UGT1A4 catalyzed the N-linked glucuronidation of TAM among recombinant UGTs (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9, UGT2B4, UGT2B7, UGT2B15, and UGT2B17) expressed in insect cells. Apparent K(m) values for TAM N-glucuronidation by human liver microsomes and recombinant UGT1A4 were 35.8 and 32.4 microM, respectively. These results strongly suggested that UGT1A4 could play a role in metabolism and excretion of TAM without Phase I metabolism in human liver. TAM N(+)-glucuronide still had binding affinity similar to TAM itself for human estrogen receptors, ERalpha and ERbeta, suggesting that TAM N(+)-glucuronide might contribute to the biological activity of TAM in vivo.

  8. Effect of Acetaminophen Alone and in Combination with Morphine and Tramadol on the Minimum Alveolar Concentration of Isoflurane in Rats

    PubMed Central

    Chavez, Julio R.; Ibancovichi, José A.; Sanchez-Aparicio, Pedro; Acevedo-Arcique, Carlos M.; Moran-Muñoz, Rafael; Recillas-Morales, Sergio

    2015-01-01

    Background It has been observed that acetaminophen potentiates the analgesic effect of morphine and tramadol in postoperative pain management. Its capacity as an analgesic drug or in combinations thereof to reduce the minimum alveolar concentration (MAC) of inhalational anesthetics represents an objective measure of this effect during general anesthesia. In this study, the effect of acetaminophen with and without morphine or tramadol was evaluated on the isoflurane MAC. Methods Forty-eight male Wistar rats were anesthetized with isoflurane in oxygen. MACISO was determined from alveolar gas samples at the time of tail clamping without the drug, after administering acetaminophen (300 mg/kg), morphine (3 mg/kg), tramadol (10 mg/kg), acetaminophen (300 mg/kg) + morphine (3 mg/kg), and acetaminophen (300 mg/kg) + tramadol (10 mg/kg). Results The control and acetaminophen groups did not present statistically significant differences (p = 0.98). The values determined for MACISO after treatment with acetaminophen + morphine, acetaminophen + tramadol, morphine, and tramadol were 0.98% ± 0.04%, 0.99% ± 0.009%, 0.97% ± 0.02%, and 0.99% ± 0.01%, respectively. Conclusions The administration of acetaminophen did not reduce the MAC of isoflurane and did not potentiate the reduction in MACISO by morphine and tramadol in rats, and therefore does not present a sparing effect of morphine or tramadol in rats anesthetized with isoflurane. PMID:26605541

  9. A case of acetaminophen (paracetamol) causing renal failure without liver damage in a child and review of literature.

    PubMed

    Ozkaya, Ozan; Genc, Gurkan; Bek, Kenan; Sullu, Yurdanur

    2010-01-01

    Acetaminophen (paracetamol) is a widely used drug and known as a safety antipyretic and analgesic drug in childhood. Acetaminophen-associated liver damage is more recognized than kidney damage. Nephrotoxicity and hepatotoxicity can be seen together after acetaminophen overdose, but renal damage without liver damage is a rarely seen entity in all age groups being reported more rarely in childhood. We present here a 16-year-old girl with renal failure without liver damage because of acetaminophen toxicity and a review of literature for pathophysiological mechanisms, clinical course, treatment, and outcome.

  10. Examination of gelling agents to produce acetaminophen jelly.

    PubMed

    Inoue, Yutaka; Iwazaki, Yuka; Onuki, Yoshinori; Funatani, Chiaki; Murata, Isamu; Kanamoto, Ikuo

    2015-01-01

    The current study used 3 types of carrageenan (denoted here as Car)-κ, ι, and λ-to prepare a jelly vehicle for acetaminophen (AAP), and then compared their usefulness as jelly vehicles. The rheological characteristics of each preparation were assessed and then drug elution from the preparation was assessed using dissolution testing. The behavior of each preparation when immersed in water was also examined using magnetic resonance imaging (MRI) in order to better understand the drug elution behaviour of each preparation. Viscoelasticity measurements revealed that 0.75 w/v%-ι-Car and 1.25 w/v%-λ-Car had viscoelasticity values equivalent to that of 0.5 w/v%-κ-Car. Dissolution testing of these 3 preparations indicated that 100% drug elution took 45 min with 0.5 w/v%-κ-Car while it took only 5 min with 0.75 w/v%-ι-Car and 1.25 w/v%-λ-Car. When deuterium oxide was added to κ-Car 0.5%, the MRI images darkened overall starting immediately after addition. The images revealed that the sample and deuterium oxide quickly mixed. In contrast, images revealed that deuterium oxide gradually penetrated κ-Car 1.0%. MRI images had uniform contrast, and deuterium oxide took 6 h or longer to penetrate the samples overall. These findings suggest that water is less apt to penetrate a jelly with an increased car concentration and a denser 3-dimensional network structure. Differences in the structure of car are said to result in better gelling, with κ having the best gelling characteristics, followed by ι and then λ. Thus, this paper discusses the role that vehicle gelling strength plays in the elution of acetaminophen.

  11. Effects of doxylamine and acetaminophen on postoperative sleep.

    PubMed

    Smith, G M; Smith, P H

    1985-05-01

    The separate and combined effects of doxylamine succinate (25 mg) and acetaminophen (1 gm) on sleep were studied by interview procedures and information from medical records of 2,931 postoperative patients. The sample contained 1,617 patients with mild or moderate pain and 1,314 who were free of pain. Each received either doxylamine alone (S), acetaminophen alone (A), a combination of both drugs (C), or placebo (P). Drug treatment was double blind and randomized separately for the pain and pain-free subsamples. Twelve measures of sleep were determined. C was more beneficial than S or A, and S and A were each superior to P. For all 12 sleep measures, the effect of the combination (C - P) approximated or exceeded the sum of the two separate effects (S - P) + (A - P). The presence of either drug tended to enhance the sleep benefit of the other. The sedative and analgesic benefits to sleep were at least additive, and some outcome measures suggested synergism. In the total sample, the contributions of sedative and analgesic similar. Among patients with pain, contributions of the analgesic surpassed those of the sedative. For patients free of pain, the sedative was better, but even pain-free patients had enhanced sleep after the analgesic. The analgesic, but not the sedative, reduced pain; the analgesic induced the feeling of being well rested and not tired; the sedative induced a feeling of being drugged. Nondrug variables (e.g., pain, sex, age, and sleep expectations) influenced sleep outcome at least as much as drugs, but randomization and the large sample prevented those extraneous variables from biasing drug comparisons.

  12. Raman detected differential scanning calorimetry of polymorphic transformations in acetaminophen.

    PubMed

    Kauffman, John F; Batykefer, Linda M; Tuschel, David D

    2008-12-15

    Acetaminophen is known to crystallize in three polymorphic forms. Thermally induced transformations between the crystalline forms and the super-cooled liquid have been observed by differential scanning calorimetry (DSC), but the assignment of calorimetric transitions to specific polymorphic transformations remains challenging, because the transition temperatures for several transformations are close to one another, and the characteristics of the observed transitions depend on experimental variables that are often poorly controlled. This paper demonstrates the simultaneous application of DSC and Raman microscopy for the observation of thermally driven transitions between polymorphs of pharmaceutical materials. Raman detected differential scanning calorimetry (RD-DSC) has been used to monitor the DSC thermograms of super-cooled liquid acetaminophen and confirms the assignment of two exothermic transitions to specific polymorphic transformations. Principal component analysis of the Raman spectra have been used to determine the number of independent components that participate in the phase transformations, and multivariate regression has been used to determine transition temperatures from the spectral data. The influence of the laser excitation source on measured DSC thermograms has also been investigated, and it has been demonstrated that a baseline shift occurs in RD-DSC when a polymorphic transformation occurs between crystalline and amorphous forms. RD-DSC has been used to examine the influence of sample aging and sample pan configuration on the observed polymorphic transformations, and both of these variables were found to influence the thermal behavior of the sample. The results demonstrate the advantage of simultaneous Raman spectroscopy and differential scanning calorimetry for the unambiguous assignment of thermally driven polymorphic transformations.

  13. N-acetylcysteine amide, a promising antidote for acetaminophen toxicity.

    PubMed

    Khayyat, Ahdab; Tobwala, Shakila; Hart, Marcia; Ercal, Nuran

    2016-01-22

    Acetaminophen (N-acetyl-p-aminophenol, APAP) is one of the most widely used over the counter antipyretic and analgesic medications. It is safe at therapeutic doses, but its overdose can result in severe hepatotoxicity, a leading cause of drug-induced acute liver failure in the USA. Depletion of glutathione (GSH) is one of the initiating steps in APAP-induced hepatotoxicity; therefore, one strategy for restricting organ damage is to restore GSH levels by using GSH prodrugs. N-acetylcysteine (NAC), a GSH precursor, is the only currently approved antidote for an acetaminophen overdose. Unfortunately, fairly high doses and longer treatment times are required due to its poor bioavailability. In addition, oral and I.V. administration of NAC in a hospital setting are laborious and costly. Therefore, we studied the protective effects of N-acetylcysteine amide (NACA), a novel antioxidant with higher bioavailability, and compared it with NAC in APAP-induced hepatotoxicity in C57BL/6 mice. Our results showed that NACA is better than NAC at a low dose (106mg/kg) in preventing oxidative stress and protecting against APAP-induced damage. NACA significantly increased GSH levels and the GSH/GSSG ratio in the liver to 66.5% and 60.5% of the control, respectively; and it reduced the level of ALT by 30%. However, at the dose used, NAC was not effective in combating the oxidative stress induced by APAP. Thus, NACA appears to be better than NAC in reducing the oxidative stress induced by APAP. It would be of great value in the health care field to develop drugs like NACA as more effective and safer options for the prevention and therapeutic intervention in APAP-induced toxicity.

  14. Serotonergic System Does Not Contribute to the Hypothermic Action of Acetaminophen.

    PubMed

    Fukushima, Akihiro; Sekiguchi, Wakana; Mamada, Kizuku; Tohma, Yumi; Ono, Hideki

    2017-02-01

    Acetaminophen (AcAP), a widely-used antipyretic and analgesic drug, has been considered to exert its effects via central mechanisms, and many studies have demonstrated that the analgesic action of AcAP involves activation of the serotonergic system. Although the serotonergic system also plays an important role in thermoregulation, the contribution of serotonergic activity to the hypothermic effect of AcAP has remained unclear. In the present study, we examined whether the serotonergic system is involved in AcAP-induced hypothermia. In normal mice, AcAP (300 mg/kg, intraperitoneally (i.p.)) induced marked hypothermia (ca. -4°C). The same dose of AcAP reduced pain response behavior in the formalin test. Pretreatment with the serotonin synthesis inhibitor DL-p-chlorophenylalanine (PCPA, 300 mg/kg/d, i.p., 5 consecutive days) substantially decreased serotonin in the brain by 70% and significantly inhibited the analgesic, but not the hypothermic action of AcAP. The same PCPA treatment significantly inhibited the hypothermia induced by the selective serotonin reuptake inhibitor fluoxetine hydrochloride (20 mg/kg, i.p.) and the serotonin 5-HT2 receptor antagonist cyproheptadine hydrochloride (3 mg/kg, i.p.). The lower doses of fluoxetine hydrochloride (3 mg/kg, i.p.) and cyproheptadine hydrochloride (0.3 mg/kg, i.p.) did not affect the AcAP-induced hypothermia. These results suggest that, in comparison with its analgesic effect, the hypothermic effect of AcAP is not mediated by the serotonergic system.

  15. Day-to-day variations during clinical drug monitoring of morphine, morphine-3-glucuronide and morphine-6-glucuronide serum concentrations in cancer patients. A prospective observational study

    PubMed Central

    Klepstad, Pål; Hilton, Priscilla; Moen, Jorunn; Kaasa, Stein; Borchgrevink, Petter C; Zahlsen, Kolbjørn; Dale, Ola

    2004-01-01

    Background The feasibility of drug monitoring of serum concentrations of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) during chronic morphine therapy is not established. One important factor relevant to drug monitoring is to what extent morphine, M6G and M3G serum concentrations fluctuate during stable morphine treatment. Methods We included twenty-nine patients admitted to a palliative care unit receiving oral morphine (n = 19) or continuous subcutaneous (sc) morphine infusions (n = 10). Serum concentrations of morphine, M6G and M3G were obtained at the same time on four consecutive days. If readmitted, the patients were followed for another trial period. Day-to-day variations in serum concentrations and ratios were determined by estimating the percent coefficient of variation (CV = (mean/SD) ×100). Results The patients' median morphine doses were 90 (range; 20–1460) mg/24 h and 135 (range; 30–440) mg/24 h during oral and sc administration, respectively. Intraindividual fluctuations of serum concentrations estimated by median coefficients of day-to-day variation were in the oral group for morphine 46%, for M6G 25% and for M3G 18%. The median coefficients of variation were lower in patients receiving continuous sc morphine infusions (morphine 10%, M6G 13%, M3G 9%). Conclusion These findings indicate that serum concentrations of morphine and morphine metabolites fluctuate. The fluctuations found in our study are not explained by changes in morphine doses, administration of other drugs or by time for collection of blood samples. As expected the day-to-day variation was lower in patients receiving continuous sc morphine infusions compared with patients receiving oral morphine. PMID:15461818

  16. Methylation, Glucuronidation, and Sulfonation of Daphnetin in Human Hepatic Preparations In Vitro: Metabolic Profiling, Pathway Comparison, and Bioactivity Analysis.

    PubMed

    Liang, Si-Cheng; Xia, Yang-Liu; Hou, Jie; Ge, Guang-Bo; Zhang, Jiang-Wei; He, Yu-Qi; Wang, Jia-Yue; Qi, Xiao-Yi; Yang, Ling

    2016-02-01

    Our previous study demonstrated that daphnetin is subject to glucuronidation in vitro. However, daphnetin metabolism is still poorly documented. This study aimed to investigate daphnetin metabolism and its consequent effect on the bioactivity. Metabolic profiles obtained by human liver S9 fractions and human hepatocytes showed that daphnetin was metabolized by glucuronidation, sulfonation, and methylation to form 6 conjugates which were synthesized and identified as 7-O-glucuronide, 8-O-glucuronide, 7-O-sulfate and 8-O-sulfate, 8-O-methylate, and 7-O-suflo-8-O-methylate. Regioselective 8-O-methylation of daphnetin was investigated using in silico docking calculations, and the results suggested that a close proximity (2.03 Å) of 8-OH to the critical residue Lysine 144 might be the responsible mechanism. Compared with glucuronidation and sulfonation pathways, the methylation of daphnetin had a high clearance rate (470 μL/min/mg) in human liver S9 fractions and contributed to a large amount (37.3%) of the methyl-derived metabolites in human hepatocyte. Reaction phenotyping studies showed the major role of SULT1A1, -1A2, and -1A3 in daphnetin sulfonation, and soluble COMT in daphnetin 8-O-methylation. Of the metabolites, only 8-O-methyldaphnetin exhibited an inhibitory activity on lymphocyte proliferation comparable to that of daphnetin. In conclusion, methylation is a crucial pathway for daphnetin clearance and might be involved in pharmacologic actions of daphnetin in humans.

  17. Comparison of enzymically glucuronidated flavonoids with flavonoid aglycones in an in vitro cellular model of oxidative stress protection.

    PubMed

    Stevenson, David E; Cooney, Janine M; Jensen, Dwayne J; Wibisono, Reginald; Adaim, Aselle; Skinner, Margot A; Zhang, Jingli

    2008-01-01

    This study modeled, in vitro, the potential effect of conjugative (phase II) metabolism on the cytoprotective capacity of fruit flavonoids against oxidative stress. Flavonoid aglycones were compared with their corresponding isomeric mixtures of glucuronides for their ability to enhance the survival of cultured human Jurkat T and neuroblastoma cells stressed with hydrogen peroxide. Various polyphenolic compounds were tested as substrates in vitro for an ovine liver glucuronyl transferase preparation. Flavonoids and their glycoside derivatives were found to be good substrates, whereas phenolic acids were either poor or nonsubstrates. Five common flavonoids were glucuronidated to prepare mixtures for bioassay testing. Glucuronidation generally weakened the cytoprotective capacities of flavonoids (in the presence of H(2)O(2)), but some compounds were weakened much more than others. The concentration that halved cell death was well below 0.5 microM for most flavonoids tested, but glucuronidation increased median effective concentration values to a range of 1-16 microM. This compares with the generally accepted physiological range (0.1-10 microM) for circulating dietary polyphenolics detected in the body. Therefore, some flavonoids may retain a reduced cytoprotective capacity in vitro, after glucuronidation, whereas others may be effectively inactivated.

  18. Structures of (-)-epicatechin glucuronide identified from plasma and urine after oral ingestion of (-)-epicatechin: differences between human and rat.

    PubMed

    Natsume, Midori; Osakabe, Naomi; Oyama, Makoto; Sasaki, Motoko; Baba, Seigo; Nakamura, Yoshimasa; Osawa, Toshihiko; Terao, Junji

    2003-04-01

    (-)-epicatechin is one of the most potent antioxidants present in the human diet. Particularly high levels are found in black tea, apples, and chocolate. High intake of catechins has been associated with reduced risk of cardiovascular diseases. There have been several reports concerning the bioavailability of catechins, however, the chemical structure of (-)-epicatechin metabolites in blood, tissues, and urine remains unclear. In the present study, we purified and elucidated the chemical structure of (-)-epicatechin metabolites in human and rat urine after oral administration. Three metabolites were purified from human urine including (-)-epicatechin-3'-O-glucuronide, 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide, and 4'-O-methyl-(-)-epicatechin-5 or 7-O-glucuronide, according to 1H- and 13C-NMR, HMBC, and LC-MS analyses. The metabolites purified from rat urine were 3'-O-methyl-(-)-epicatechin, (-)-epicatechin-7-O-glucuronide, and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide. These compounds were also detected in the blood of humans and rats by LC-MS. The presence of these metabolites in blood and urine suggests that catechins are metabolized and circulated in the body after administration of catechin-containing foods.

  19. Interpretation of the presence of 6-monoacetylmorphine in the absence of morphine-3-glucuronide in urine samples: evidence of heroin abuse.

    PubMed

    von Euler, Mia; Villén, Tomas; Svensson, Jan-Olof; Ståhle, Lars

    2003-10-01

    The presence of morphine in a urinary sample may be caused not only by intake of heroin but also by intake of poppy-seed-containing food shortly before urine sampling or intake of drugs containing morphine, ethyl morphine, or codeine. To facilitate the interpretation, the heroin-specific metabolite 6-monoacetylmorphine (6-MAM) can be analyzed along with morphine-3-glucuronide (M3G) in an LC-MS verification analysis. In sporadic samples positive in the immunologic opiate screening test, 6-MAM, but not M3G, was found. To systematically analyze the finding all specimens with positive 6-MAM and/or M3G found during a 1-year period were investigated (n = 1923). Of these, 423 were positive for 6-MAM. In 32 (7.6%) of the samples 6-MAM was detected while the M3G concentrations were below cutoff (300 ng/mL) and in some cases even below the limit of detection (15 ng/mL). The 32 samples with this excretion pattern came from 13 different individuals, all but one with previously known heroin abuse. Eleven urine samples, nine containing M3G and 6-MAM and two with only 6-MAM, were also analyzed for the presence of heroin. In six samples, including the two with only 6-MAM, heroin was detected. There are several plausible explanations for these findings. The intake may have taken place shortly before urine sampling. High concentrations of heroin and 6-MAM may inhibit UGT 2B7, the enzyme responsible for glucuronidation of morphine. The hydrolyzation of 6-MAM to morphine may be disturbed by either internal or external causes. To elucidate this, further studies are required. Nevertheless, our finding demonstrates that routine measurement of 6-MAM when verifying opioid-positive immunologic screening results facilitates interpretation of low concentrations of M3G in urine specimens.

  20. Inhibition of morphine metabolism by ketamine.

    PubMed

    Qi, Xiaoxin; Evans, Allan M; Wang, Jiping; Miners, John O; Upton, Richard N; Milne, Robert W

    2010-05-01

    Clinical observation of a synergistic effect of ketamine on morphine analgesia remains controversial. Although a pharmacodynamic basis for an interaction has been explored in animal and clinical studies, the possibility of a pharmacokinetic mechanism has not been investigated. Whereas both morphine and morphine-6-glucuronide are effective analgesics, morphine-3-glucuronide (M3G) lacks activity. Thus, changes in the metabolism and disposition of morphine may result in an altered response. First, we investigated the interaction between morphine and ketamine in the isolated perfused rat liver preparation. The clearance of morphine was decreased from 16.8 +/- 4.6 ml/min in the control period to 7.7 +/- 2.8 ml/min in the ketamine-treatment period, with the formation clearance of M3G decreasing from 8.0 +/- 4.1 ml/min to 2.1 +/- 1.1 ml/min. Fractional conversion of morphine to M3G was significantly decreased from 0.46 +/- 0.17 in the control period to 0.28 +/- 0.14 upon the addition of ketamine. The possible mechanism of the interaction was further investigated in vitro with rat liver microsomes as the enzyme source. The formation of M3G followed single-enzyme Michaelis-Menten kinetics, with a mean apparent K(m) of 2.18 +/- 0.45 mM and V(max) of 8.67 +/- 0.59 nmol/min/mg. Ketamine inhibited morphine 3-glucuronidation noncompetitively, with a mean K(i) value of 33.3 +/- 7.9 microM. The results demonstrate that ketamine inhibits the glucuronidation of morphine in a rat model.

  1. Identification of novel toxicity-associated metabolites by metabolomics and mass isotopomer analysis of acetaminophen metabolism in wild-type and Cyp2e1-null mice.

    PubMed

    Chen, Chi; Krausz, Kristopher W; Idle, Jeffrey R; Gonzalez, Frank J

    2008-02-22

    CYP2E1 is recognized as the most important enzyme for initiation of acetaminophen (APAP)-induced toxicity. In this study, the resistance of Cyp2e1-null mice to APAP treatment was confirmed by comparing serum aminotransferase activities and blood urea nitrogen levels in wild-type and Cyp2e1-null mice. However, unexpectedly, profiling of major known APAP metabolites in urine and serum revealed that the contribution of CYP2E1 to APAP metabolism decreased with increasing APAP doses administered. Measurement of hepatic glutathione and hydrogen peroxide levels exposed the importance of oxidative stress in determining the consequence of APAP overdose. Subsequent metabolomic analysis was capable of constructing a principal components analysis (PCA) model that delineated a relationship between urinary metabolomes and the responses to APAP treatment. Urinary ions high in wild-type mice treated with 400 mg/kg APAP were elucidated as 3-methoxy-APAP glucuronide (VII) and three novel APAP metabolites, including S-(5-acetylamino-2-hydroxyphenyl)mercaptopyruvic acid (VI, formed by a Cys-APAP transamination reaction in kidney), 3,3'-biacetaminophen (VIII, an APAP dimer), and a benzothiazine compound (IX, originated from deacetylated APAP), through mass isotopomer analysis, accurate mass measurement, tandem mass spectrometry fragmentation, in vitro reactions, and chemical treatments. Dose-, time-, and genotype-dependent appearance of these minor APAP metabolites implied their association with the APAP-induced toxicity and potential biomarker application. Overall, the oxidative stress elicited by CYP2E1-mediated APAP metabolism might significantly contribute to APAP-induced toxicity. The combination of genetically modified animal models, mass isotopomer analysis, and metabolomics provides a powerful and efficient technical platform to characterize APAP-induced toxicity through identifying novel biomarkers and unraveling novel mechanisms.

  2. Formulation and Characterization of Acetaminophen Nanoparticles in Orally Disintegrating Films

    NASA Astrophysics Data System (ADS)

    AI-Nemrawi, Nusaiba K.

    The purpose of this study is to prepare acetaminophen loaded nanoparticles to be cast directly, while still in the emulsion form, into Orally Disintegrating Films (ODF). By casting the nanoparticles in the films, we expected to keep the particles in a stable form where the nanoparticles would be away from each other to prevent their aggregation. Once the films are applied on the buccal mucosa, they are supposed to dissolve within seconds, releasing the nanoparticles. Then the nanoparticles could be directly absorbed through the mucosa to the blood stream and deliver acetaminophen there. The oral cavity mucosa is one of the most attractive sites for systemic drug delivery due to its high permeability and blood supply. Furthermore, it is robust and shows short recovery times after stress or damage, and the drug bypasses first pass effect and avoids presystemic elimination in the GI tract. Nanoencapsulation increases drug efficacy, specificity, tolerability and therapeutic index. These Nanocapsules have several advantages in the protection of premature degradation and interaction with the biological environment, enhancement of absorption into a selected tissue, bioavailability, retention time and improvement of intracellular penetration. The most important characteristics of nanoparticles are their size, encapsulation efficiency (EE), zeta potential (surface charge), and the drug release profiles. Unfortunately, nanoparticles tend to precipitate or aggregate into larger particles within a short time after preparation or during storage. Some solutions for this problem were mentioned in literature including lyophilization and spray drying. These methods are usually expensive and give partial solutions that might have secondary problems; such as low re-dispersion efficacy of the lyophilized NPs. Furthermore, most of the formulations of NPs are invasive or topical. Few formulas are available to be given orally. Fast disintegrating films (ODFs) are rapidly gaining interest

  3. [Glucuronidation of antitumour therapeutics--detoxification, mechanism of resistance or prodrug formation?].

    PubMed

    Mróz, Anna; Mazerska, Zofia

    2015-12-31

    The physiological role of phase I and II of xenobiotic biotransformations is their detoxification and better excretion outside the organism. UDP-glucuronosyltransferases (UGTs) being the enzymes of phase II metabolism catalyse the conjugation of glucuronic acid to the lipophilic substrate by its specific nucleophilic group. UGT isoenzymes of various substrate specificities and different expression profiles in selected tissues belong to the large UGT superfamily. Usually, glucuronidation is the detoxification process, but sometimes (morphine, tamoxifen) glucuronides express biological activity higher than or comparable to the native compound. The level of UGT gene expression is individual for patients, because of their genetic status as well as epigenetic conditions. Also, xenobiotics are able to modulate UGT level and gene expression by the interaction with nuclear receptors. Moreover, one can find a lower level of UGT in the tumour compared to normal tissue, which results in the protection against deactivation of the drug and in the promotion of its selective activity in tumor tissue. On the other hand, UGT activity is considered as the possible cause of resistance to chemotherapy. Metabolism by hepatic and intestinal UGT isoenzymes is responsible for the "first-pass effect", whereas acquired resistance consists in the induction of UGT gene expression by the chemotherapeutic or its metabolite. Moreover, UGT induction can be associated with the induction of membrane transporters, particularly proteins of the ABC family, responsible for drug excretion outside the cell. The above resistance effects can be fortified by the overexpression of selected UGT isoenzymes sometimes observed in specific types of tumours. It is also considered that many advanced tumours are characterized by a higher level of β-glucuronidase. This enzyme has a chance to be the molecular target of directed antitumour therapy, as it catalyses β-glucuronide hydrolysis, leading to active aglycones.

  4. Interactions between morphine and the morphine-glucuronides measured by conditioned place preference and locomotor activity.

    PubMed

    Vindenes, Vigdis; Ripel, Ase; Handal, Marte; Boix, Fernando; Mørland, Jørg

    2009-07-01

    After intake of heroin or morphine, active metabolites are formed in the body. The two most important morphine metabolites are morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G). M6G and M3G are present for longer time periods and in higher concentrations than the parent drug, but their potential contribution to reward and to development of dependence and addiction is not clear. We tested the effects of morphine and M6G separately (doses of 10, 20, 30 and 50 micromol/kg), administered together, and also in combination with with 200 microm l/kg M3G in male C57BL/6J-Bom mice. M3G in doses of 50, 100, 200, 300 and 400 micromol/kg were also tested alone. We evaluated the rewarding effects in a conditioning place preference (CPP) model and the psychomotor stimulating effects by recording locomotor activity. Mice were subjected to three consecutive conditioning days with drugs or saline before testing. Changes in locomotor activity from conditioning day one to day three were also compared to the expression of CPP on the test day. This study revealed that coadministration of morphine and M6G induced CPP of similar magnitude to the sum of equimolar doses of these compounds alone, and different ratios of the two drugs did not affect the results. M3G did not cause CPP and reduced the CPP induced by both morphine and M6G when coadministered with these drugs. Morphine induced locomotor activity was reduced by coadministration of M3G, but this was not seen when M3G was co-injected with M6G. The changes in locomotor activity during the conditioning periods did not correlated with the expression of CPP. This study revealed that the morphine-glucuronides in different and complex ways can influence the pharmacological effects of psychomotor activation and reward observed after intake of morphine.

  5. Glucuronidated Quercetin Lowers Blood Pressure in Spontaneously Hypertensive Rats via Deconjugation

    PubMed Central

    Galindo, Pilar; Rodriguez-Gómez, Isabel; González-Manzano, Susana; Dueñas, Montserrat; Jiménez, Rosario; Menéndez, Carmen; Vargas, Félix; Tamargo, Juan; Santos-Buelga, Celestino; Pérez-Vizcaíno, Francisco; Duarte, Juan

    2012-01-01

    Background Chronic oral quercetin reduces blood pressure and restores endothelial dysfunction in hypertensive animals. However, quercetin (aglycone) is usually not present in plasma, because it is rapidly metabolized into conjugated, mostly inactive, metabolites. The aim of the study is to analyze whether deconjugation of these metabolites is involved in the blood pressure lowering effect of quercetin. Methodology/Principal Findings We have analyzed the effects on blood pressure and vascular function in vitro of the conjugated metabolites of quercetin (quercetin-3-glucuronide, Q3GA; isorhamnetin-3-glucuronide, I3GA; and quercetin-3′-sulfate, Q3'S) in spontaneously hypertensive rats (SHR). Q3GA and I3GA (1 mg/kg i.v.), but not Q3'S, progressively reduced mean blood pressure (MBP), measured in conscious SHR. The hypotensive effect of Q3GA was abolished in SHR treated with the specific inhibitor of β-glucuronidase, saccharic acid 1,4-lactone (SAL, 10 mg/ml). In mesenteric arteries, unlike quercetin, Q3GA had no inhibitory effect in the contractile response to phenylephrine after 30 min of incubation. However, after 1 hour of incubation Q3GA strongly reduced this contractile response and this effect was prevented by SAL. Oral administration of quercetin (10 mg/Kg) induced a progressive decrease in MBP, which was also suppressed by SAL. Conclusions Conjugated metabolites are involved in the in vivo antihypertensive effect of quercetin, acting as molecules for the plasmatic transport of quercetin to the target tissues. Quercetin released from its glucuronidated metabolites could be responsible for its vasorelaxant and hypotensive effect. PMID:22427863

  6. Resveratrol and some glucosyl, glucosylacyl, and glucuronide derivatives reduce Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes Scott A adhesion to colonic epithelial cell lines.

    PubMed

    Selma, María V; Larrosa, Mar; Beltrán, David; Lucas, Ricardo; Morales, Juan C; Tomás-Barberán, Francisco; Espín, Juan C

    2012-08-01

    The efficacy of resveratrol and some glucosyl, glucosylacyl, and glucuronide derivatives in inhibiting the adhesion of Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes Scott A to Caco-2 and HT-29 colonic cells was investigated. The three bacteria strains were capable of adhering to both colonic epithelial cell lines, which responded by producing the pro-inflammatory interleukin 8 (IL-8). Adhesion inhibition of E. coli O157:H7 and S. Typhimurium to colonic cells was ≥60 and ≥40%, respectively, when resveratrol and most of the resveratrol derivatives were applied. Lower adhesion inhibition was observed for the bacteria with higher adherence potential, L. monocytogenes (≥20%). Resveratrol-3-O-(6'-O-butanoyl)-β-D-glucopyranoside (BUT) (50 and 100 μM) and resveratrol-3-O-(6'-O-octanoyl)-β-D-glucopyranoside (OCT) (50 μM) reduced IL-8 secretion by 100%. These results suggest that one mechanism for the beneficial attributes of resveratrol and especially the derivatives BUT and OCT could be the ability to reduce the adhesion and consequent pro-inflammatory cytokine production in intestinal epithelial cells in response to pathogen adhesion. The potential use of these compounds in the prevention of foodborne infections, intestinal homeostasis loss, and inflammatory bowel diseases could be another step in finding coadjuvants or alternatives to antibiotic treatments.

  7. Acute acetaminophen (paracetamol) ingestion improves time to exhaustion during exercise in the heat.

    PubMed

    Mauger, Alexis R; Taylor, Lee; Harding, Christopher; Wright, Benjamin; Foster, Josh; Castle, Paul C

    2014-01-01

    Acetaminophen (paracetamol) is a commonly used over-the-counter analgesic and antipyretic and has previously been shown to improve exercise performance through a reduction in perceived pain. This study sought to establish whether its antipyretic action may also improve exercise capacity in the heat by moderating the increase in core temperature. On separate days, 11 recreationally active participants completed two experimental time-to-exhaustion trials on a cycle ergometer in hot conditions (30°C, 50% relative humidity) after ingesting a placebo control or an oral dose of acetaminophen in a randomized, double-blind design. Following acetaminophen ingestion, participants cycled for a significantly longer period of time (acetaminophen, 23 ± 15 min versus placebo, 19 ± 13 min; P = 0.005; 95% confidence interval = 90-379 s), and this was accompanied by significantly lower core (-0.15°C), skin (-0.47°C) and body temperatures (0.19°C; P < 0.05). In the acetaminophen condition, participants also reported significantly lower ratings of thermal sensation (-0.39; P = 0.015), but no significant change in heart rate was observed (P > 0.05). This is the first study to demonstrate that an acute dose of acetaminophen can improve cycling capacity in hot conditions, and that this may be due to the observed reduction in core, skin and body temperature and the subjective perception of thermal comfort. These findings suggest that acetaminophen may reduce the thermoregulatory strain elicited from exercise, thus improving time to exhaustion.

  8. Eucalyptus globulus extract protects upon acetaminophen-induced kidney damages in male rat

    PubMed Central

    Dhibi, Sabah; Mbarki, Sakhria; Elfeki, Abdelfettah; Hfaiedh, Najla

    2014-01-01

    Plants have historically been used in treating many diseases. Eucalyptus globules, a rich source of bioactive compounds, and have been shown to possess antioxidative properties. The purpose of this study, carried out on male Wistar rats, was to evaluate the beneficial effects of Eucalyptus globulus extract upon acetaminophen-induced damages in kidney. Our study is realized in the Department of Biology, Faculty of Sciences of Sfax (Tunisia). 32 Wistar male rats; were divided into 4 batches: a control group (n=8), a group of rats treated with acetaminophen (goomg/kg) by intraperitoneal injection during 4 days (n=8), a group receiving Eucalyptus globulus extract (130 mg of dry leaves/kg/day) in drinking water during 42 days after 2 hours of acetaminophen administration (during 4 days) (n=8) and group received only Eucalyptus (n=8) during 42 days. After 6 weeks, animals from each group were rapidly sacrificed by decapitation. Blood serum was obtained by centrifugation. Under our experimental conditions, acetaminophen poisoning resulted in an oxidative stress evidenced by statistically significant losses in the activities of catalase (CAT), superoxide-dismutase (SOD), glutathione-peroxidase (GPX) activities and an increase in lipids peroxidation level in renal tissue of acetaminophen-treated group compared with the control group. Acetaminophen also caused kidney damage as evident by statistically significant (p<0.05) increase in levels of creatinine and urea and decreased levels of uric acid and proteins in blood. Histological analysis demonstrated alteration of proximal tubules, atrophy of the glomerule and dilatation of urinary space. Previous administration of plant extract is found to alleviate this acetaminophen-induced damage. PMID:24856382

  9. Prediction of color changes in acetaminophen solution using the time-temperature superposition principle.

    PubMed

    Mochizuki, Koji; Takayama, Kozo

    2016-01-01

    A prediction method for color changes based on the time-temperature superposition principle (TTSP) was developed for acetaminophen solution. Color changes of acetaminophen solution are caused by the degradation of acetaminophen, such as hydrolysis and oxidation. In principle, the TTSP can be applied to only thermal aging. Therefore, the impact of oxidation on the color changes of acetaminophen solution was verified. The results of our experiment suggested that the oxidation products enhanced the color changes in acetaminophen solution. Next, the color changes of acetaminophen solution samples of the same head space volume after accelerated aging at various temperatures were investigated using the Commission Internationale de l'Eclairage (CIE) LAB color space (a*, b*, L* and ΔE*ab), following which the TTSP was adopted to kinetic analysis of the color changes. The apparent activation energies using the time-temperature shift factor of a*, b*, L* and ΔE*ab were calculated as 72.4, 69.2, 72.3 and 70.9 (kJ/mol), respectively, which are similar to the values for acetaminophen hydrolysis reported in the literature. The predicted values of a*, b*, L* and ΔE*ab at 40 °C were obtained by calculation using Arrhenius plots. A comparison between the experimental and predicted values for each color parameter revealed sufficiently high R(2) values (>0.98), suggesting the high reliability of the prediction. The kinetic analysis using TTSP was successfully applied to predicting the color changes under the controlled oxygen amount at any temperature and for any length of time.

  10. Comparison of Oral Acetaminophen Versus Ibuprofen in Premature Infants With Patent Ductus Arteriosus

    PubMed Central

    Bagheri, Mohammad Mehdi; Niknafs, Pedram; Sabsevari, Fatemeh; Torabi, Mohammad Hosein; Bahman Bijari, Bahareh; Noroozi, Elahe; Mossavi, Hamid

    2016-01-01

    Background Patent ductus arteriosus (PDA) is a common cause of morbidity. The aim of this study was to compare the efficacy of oral Acetaminophen and oral Ibuprofen for the closure of patent ductus arteriosus (PDA) in preterm infants. Objectives This study demonstrated that, there was no significant difference between treatment of PDA with either oral Acetaminophen or oral Ibuprofen in preterm neonates. Patients and Methods This clinical trial, randomized study, enrolled 120 infants, with a gestational age of < 37 weeks, who were admitted in neonatal intensive care unit of Afzalipour hospital, Kerman, Iran, in 2014. PDA was confirmed echocardiographically. The trial was registered in Iranian registry of clinical trials (Reg. No. 25542). Sixty-seven infants received oral Acetaminophen (15mg/kg every six hours for three days) and 62 infants received Ibuprofen (an initial dose of 20 mg/kg, followed by 10 mg/kg at 24 and 48 hours). To evaluate the efficacy of the treatment, a second echocardiography was done after completing the treatment. Results After the first course of the treatment, PDA closed in 55 (82.1 %) patients who received oral Acetaminophen vs. 47 (75.8 %) of those given oral Ibuprofen (P = 0.38). After the second course of treatment, PDA closed in 50 % of oral Acetaminophen group and 73.3% of oral Ibuprofen group (P = 0.21). Conclusions This study demonstrated that, there was no significant difference between treatment of PDA with either oral Acetaminophen or oral Ibuprofen in preterm neonates. Oral Ibuprofen can effectively close PDA but is unfortunately associated with some adverse effects limiting its utility thus we studied an alternative drug with similar efficacy and less adverse effects. This study has recommends Acetaminophen with minimal complications for the treatment of PDA in preterm neonates instead of Ibuprofen. PMID:27713809

  11. Voucher-based reinforcement for alcohol abstinence using the ethyl-glucuronide alcohol biomarker.

    PubMed

    McDonell, Michael G; Howell, Donelle N; McPherson, Sterling; Cameron, Jennifer M; Srebnik, Debra; Roll, John M; Ries, Richard K

    2012-01-01

    This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase. The percentage of negative urines was 35% during the first baseline phase, 69% during the C phase, and 20% during the return-to-baseline phase. Results suggest that EtG urine tests may be a feasible method to deliver CM to promote alcohol abstinence.

  12. Two new glucuronide saponins, Achyranthosides G and H, from Achyranthes fauriei root.

    PubMed

    Ando, Hidehiro; Fukumura, Motonori; Hori, Yumiko; Hirai, Yasuaki; Toriizuka, Kazuo; Kuchino, Yoshiyuki; Ida, Yoshiteru

    2008-01-01

    Two oleanolic acid saponins named achyranthosides G (1) and H (2) were newly isolated from Achyranthes fauriei root as methyl esters in addition to methyl esters of achyranthosides A - F and five oleanolic acid glucuronides (chikusetsusaponins IVa, V, 28-deglucosyl chikusetsusaponin V, pseudoginsenoside RT(1), and oleanolic acid 3-O-beta-D-glucuronopyranoside) as well as oleanolic acid 28-O-beta-D-glucopyranoside, beta-ecdysterone, and polypodine B. Their structures were characterized as follows on the basis of the chemical and spectroscopic evidences.

  13. Neuroexcitatory effects of morphine and hydromorphone: evidence implicating the 3-glucuronide metabolites.

    PubMed

    Smith, M T

    2000-07-01

    1. Morphine is recommended by the World Health Organization as the drug of choice for the management of moderate to severe cancer pain. 2. Education of health professionals in the past decade has resulted in a large increase in the prescribing of opioids, such as morphine, and in the magnitude of the doses administered, resulting in an improvement in the quality of pain relief available for many cancer patients. 3. However, the reported incidence of neuroexcitatory side effects (allodynia, myoclonus, seizures) in patients administered large doses of systemic morphine or its structural analogue, hydromorphone (HMOR), has also increased. 4. Clinically, increasing the magnitude of the morphine or HMOR dose administered to patients already exhibiting neuroexcitatory opioid related side effects, results in an exacerbation rather than an attenuation of the excitatory behaviours. 5. In contrast, cessation of the opioid or rotation to a structurally dissimilar opioid (e.g. from morphine/HMOR to methadone or fentanyl), usually results in a restoration of analgesia and resolution of the neuroexcitatory opioid side effects over a period of hours to days. 6. To explain the clinical success of 'opioid rotation', it is essential to understand the in vivo metabolic fate of morphine and HMOR. 7. Following systemic administration, morphine and HMOR are metabolized primarily to the corresponding 3-glucuronide metabolites, morphine-3-glucuronide (M3G) and hydromorphone-3-glucuronide (H3G), which are not only devoid of analgesic activity but evoke a range of dose-dependent excitatory behaviours, including allodynia, myoclonus and seizures, following intracerebroventricular (i.c.v.) administration to rats. 8. Several studies have shown that, following chronic oral or subcutaneous morphine administration to patients with cancer pain, the cerebrospinal fluid (CSF) concentrations of M3G exceed those of morphine and morphine-6-glucuronide (analgesically active morphine metabolite) by

  14. Metabolite kinetics: formation of acetaminophen from deuterated and nondeuterated phenacetin and acetanilide on acetaminophen sulfation kinetics in the perfused rat liver preparation

    SciTech Connect

    Pang, K.S.; Waller, L.; Horning, M.G.; Chan, K.K.

    1982-07-01

    The role of hepatic intrinsic clearance for metabolite formation from various precursors on subsequent metabolite elimination was was investigated in the once-through perfused rat liver preparation. Two pairs of acetaminophen precursors: (/sup 14/C) phenacetin-d5 and (/sup 3/H) phenacetin-do, (/sup 14/C) acetanilide and (/sup 3/H) phenacetin were delivered by constant flow (10 ml/min/liver) either by normal or retrograde perfusion to the rat liver preparations. The extents of acetaminophen sulfation were compared within the same preparation. The data showed that the higher the hepatocellular activity (intrinsic clearance) for acetaminophen formation, the greater the extent of subsequent acetaminophen sulfation. The findings were explained on the basis of blood transit time and metabolite duration time. Because of blood having only a finite transit time in liver, the longer the drug requires for metabolite formation, the less time will remain for metabolite sulfation and the less will be the degree of subsequent sulfation. Conversely, when the drug forms the primary metabolite rapidly, a longer time will remain for the metabolite to be sulfated in liver to result in a greater degree of metabolite sulfation. Finally, the effects of hepatic intrinsic clearances for metabolite formation and zonal distribution of enzyme systems for metabolite formation and elimination in liver are discussed.

  15. Biliary excretion of acetaminophen-glutathione as an index of toxic activation of acetaminophen: effect of chemicals that alter acetaminophen hepatotoxicity

    SciTech Connect

    Madhu, C.; Gregus, Z.; Klaassen, C.D.

    1989-03-01

    Acetaminophen (AA) is converted, presumably by cytochrome P-450, to an electrophile which is conjugated with glutathione (GS). AA-GS is excreted into bile, therefore the biliary excretion rate of AA-GS may reflect the rate of activation of AA in vivo. In order to test this hypothesis, the effect of agents capable of altering the activation of AA including cytochrome P-450 inducers and inhibitors, cobaltous chloride which decreases the amount of P-450, prostaglandin synthetase inhibitors (indomethacin and naproxen), antioxidants (butylated hydroxyanisole, alpha-tocopherol, ascorbic acid and ascorbic acid palmitate) and other chemicals known to decrease AA hepatotoxicity (dimethylsulfoxide and cysteamine), on the biliary excretion of AA-GS was studied in hamsters, the species most sensitive to AA-induced hepatotoxicity. The biliary excretion of AA-GS increased linearly up to 1 mmol/kg of AA i.v., but at higher dosages exhibited saturation kinetics. Dosages above 0.5 mmol/kg lowered hepatic GS concentration. Of the cytochrome P-450 inducers, 3-methylcholanthrene and 2,3,7,8-tetrachlorodibenzo-p-dioxin, increased the biliary excretion of AA-GS (2.9- and 3.2-fold, respectively) whereas ethanol and isoniazid did not affect it, and pregnenolone-16 alpha-carbonitrile tended to decrease it (43%). Phenobarbital tended to increase the biliary excretion of AA-GS, but not in a statistically significant manner. Several cytochrome P-450 inhibitors (metyrapone, 8-methoxypsoralen, 2-(4,6-dichloro-biphenyloxy) ethylamine, alpha-naphthoflavone and cimetidine) decreased the biliary excretion of AA-GS, although SKF 525-A and piperonyl butoxide did not. Cobaltous chloride decreased dramatically the biliary excretion of AA-GS.

  16. Liquid Chromatography-Tandem Mass Spectrometry Assay to Detect Ethyl Glucuronide in Human Fingernail: Comparison to Hair and Gender Differences

    PubMed Central

    Jones, Joseph; Jones, Mary; Plate, Charles; Lewis, Douglas; Fendrich, Michael; Berger, Lisa; Fuhrmann, Daniel

    2015-01-01

    Over the past decade, the use of hair specimens for the long-term detection of the alcohol biomarker ethyl glucuronide has been increasing in popularity and usage. We evaluated the usefulness of fingernail clippings as a suitable alternative to hair for ethyl glucuronide detection. A liquid chromatography-tandem mass spectrometry method for the detection of ethyl glucuronide in fingernail clippings was fully validated and used to analyze the hair and/or fingernail specimens of 606 college-aged study participants. The limit of detection was 2 pg/mg, the limit of quantitation was 8 pg/mg and the method was linear from 8 to 2000 pg/mg. Intra- and inter-assay imprecision studies at three different concentrations (20, 40, 200 pg/mg) were all within 7.8% and all intra- and inter-assay bias studies at these levels were within 115.1% of target concentration. Ethyl glucuronide levels in fingernail (mean = 29.1 ± 55.6 pg/mg) were higher than ethyl glucuronide levels in hair (mean = 9.48 ± 22.3 pg/mg) and a correlation of the matched pairs was observed (r = 0.552, P < 0.01, n = 529). Evaluating each gender separately revealed that the correlation of male fingernail to male hair was large and significant (r = 0.782, P < 0.01, n = 195) while female hair to female fingernail was small yet significant (r = 0.249, P < 0.01, n = 334). The study results demonstrated that fingernail may be a suitable alternative to hair for ethyl glucuronide detection and may be the preferred sample type due to the lack of a gender bias. PMID:27134762

  17. Identification of Recent Cannabis Use: Whole-Blood and Plasma Free and Glucuronidated Cannabinoid Pharmacokinetics following Controlled Smoked Cannabis Administration

    PubMed Central

    Schwope, David M.; Karschner, Erin L.; Gorelick, David A.; Huestis, Marilyn A.

    2013-01-01

    BACKGROUND Δ9-Tetrahydrocannabinol (THC) is the most frequently observed illicit drug in investigations of accidents and driving under the influence of drugs. THC-glucuronide has been suggested as a marker of recent cannabis use, but there are no blood data following controlled THC administration to test this hypothesis. Furthermore, there are no studies directly examining whole-blood cannabinoid pharmacokinetics, although this matrix is often the only available specimen. METHODS Participants (9 men, 1 woman) resided on a closed research unit and smoked one 6.8% THC cannabis cigarette ad libitum. We quantified THC, 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), cannabinol (CBN), THC-glucuronide and THCCOOH-glucuronide directly in whole blood and plasma by liquid chromatography/ tandem mass spectrometry within 24 h of collection to obviate stability issues. RESULTS Median whole blood (plasma) observed maximum concentrations (Cmax) were 50 (76), 6.4 (10), 41 (67), 1.3 (2.0), 2.4 (3.6), 89 (190), and 0.7 (1.4) μg/L 0.25 h after starting smoking for THC, 11-OH-THC, THCCOOH, CBD, CBN, and THCCOOH-glucuronide, respectively, and 0.5 h for THC-glucuronide. At observed Cmax, whole-blood (plasma) detection rates were 60% (80%), 80% (90%), and 50% (80%) for CBD, CBN, and THC-glucuronide, respectively. CBD and CBN were not detectable after 1 h in either matrix (LOQ 1.0 μg/L). CONCLUSIONS Human whole-blood cannabinoid data following cannabis smoking will assist whole blood and plasma cannabinoid interpretation, while furthering identification of recent cannabis intake. PMID:21836075

  18. Identification of glucuronide metabolites of d- and 1-methadone in bile from the isolated perfused rat liver.

    PubMed

    Lynn, R K; Leger, R M; Gerber, N

    1976-09-01

    Three hydroxylated metabolites of methadone, 2-ethyl-3-(dihydroxyphenyl)-5-methyl-3-phenylpyrroline (di-HO-EMDP), 2-ethyl-3-(hydroxy-methoxy-phenyl)-5-methyl-3-phenylpyrroline (HO-MeO-EMDP) and 2-ethyl-3-(hydroxy-phenyl)-5-methyl-3-phenylpyrroline (HO-EMDP) were excreted as O-glucuronide conjugates in bile from the isolated perfused rat liver following the addition of either d- or 1-methadone to the perfusate. These glucuronide metabolites were identified as intact molecules by combined gas chromatographic-mass spectrometric (GC-MS) analysis of their permethylated derivatives.

  19. Simultaneous determination of THC-COOH and THC-COOH-glucuronide in urine samples by LC/MS/MS.

    PubMed

    Weinmann, W; Vogt, S; Goerke, R; Müller, C; Bromberger, A

    2000-09-11

    A fast method using liquid-liquid extraction and HPLC/tandem-mass spectrometry (LC/MS/MS) was developed for the simultaneous detection of 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid beta-glucuronide (THC-COOH-glucuronide) and 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. This highly specific method, which combines chromatographic separation and MS/MS analysis, can be used for the confirmation of positive immunoassay results even without hydrolysis of the sample or derivatisation of extracts. Liquid-liquid extraction was optimised: with ethylacetate/diethylether (1:1, v/v) THC-COOH-glucuronide and THC-COOH could be extracted in one step. Molecular ions of the glucuronide (MH(+), m/z 521) and THC-COOH (MH(+), m/z 345) were generated using a PE/SCIEX turboionspray source in positive ionisation mode; specific fragmentation was performed in the collision cell of an API 365 triple-quadrupole mass spectrometer and yielded major fragments at m/z 345 (for THC-COOH-glucuronide) and m/z 327 as well as m/z 299 for both cannabinoids. Chromatographic separation was performed using a reversed-phase C8 column and gradient elution with 0.1% formic acid/1 mM ammonium formate and acetonitrile/0.1% formic acid. Retention times were 22.2 min for the glucuronide and 26.8 min for THC-COOH. After enzymatic hydrolysis of urine samples with beta-glucuronidase/arylsulfatase (37 degrees C, 5 h), THC-COOH-glucuronide was no longer detectable by LC/MS/MS in urine samples. However, the THC-COOH concentration was increased. For quantitation of THC-COOH, THC-COOH-D(3) was added to the urine samples as internal standard prior to analysis. From the difference of THC-COOH in the native urine and urine after enzymatic hydrolysis, molar concentration ratios of THC-COOH-glucuronide/THC-COOH in urine samples of cannabis users were determined and found to be between 1.3 and 4.5.

  20. Effect of Methylsulfonylmethane Pretreatment on Aceta-minophen Induced Hepatotoxicity in Rats

    PubMed Central

    Bohlooli, Shahab; Mohammadi, Sadollah; Amirshahrokhi, Keyvan; Mirzanejad-asl, Hafez; Yosefi, Mohammad; Mohammadi-Nei, Amir; Chinifroush, Mir Mehdi

    2013-01-01

    Objective(s): Methylsulfonylmethane (MSM) is a sulfur-containing compound found in a wide range of human foods including fruits, vegetables, grains and beverages. In this study the effect of MSM pretreatment on acetaminophen induced liver damage was investigated. Materials and Methods: Male Sprague Dawley rats were pretreated with 100 mg/kg MSM for one week. On day seven rats were received acetaminophen (850 mg/kg, intraperitoneal). Twenty-four hours later, blood samples were taken to determine serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Tissue samples of liver were also taken for the determination of the levels of malondialdehyde (MDA); total glutathione (GSH), superoxide dismutase (SOD), and myeloperoxidase (MPO) activity together with histopathological observations. Results: High dose of acetaminophen administration caused a significant decrease in the GSH level of the liver tissue, which was accompanied with a decrease in SOD activity and increases in tissue MDA level and MPO activity. Serum ALT, AST levels were also found elevated in the acetaminophen-treated group. Pretreatment with MSM for one week was significantly attenuated all of these biochemical indices. Conclusion: Our findings suggest that MSM pretreatment could alleviate hepatic injury induced by acetaminophen intoxication, may be through its sulfur donating and antioxidant effects. PMID:24106592

  1. Comparative study of the adsorption of acetaminophen on activated carbons in simulated gastric fluid.

    PubMed

    Rey-Mafull, Carlos A; Tacoronte, Juan E; Garcia, Raquel; Tobella, Jorge; Llópiz, Julio C; Iglesias, Alberto; Hotza, Dachamir

    2014-01-01

    Samples of commercial activated carbons (AC) obtained from different sources: Norit E Supra USP, Norit B Test EUR, and ML (Baracoa, Cuba) were investigated. The adsorption of acetaminophen, Co = 2500 mg/L, occured in simulated gastric fluid (SGF) at pH 1.2 in contact with activated carbon for 4 h at 310 K in water bath with stirring. Residual acetaminophen was monitored by UV visible. The results were converted to scale adsorption isotherms using alternative models: Langmuir TI and TII, Freundlich, Dubinin-Radushkevich (DR) and Temkin. Linearized forms of the characteristic parameters were obtained in each case. The models that best fit the experimental data were Langmuir TI and Temkin with R(2) ≥0.98. The regression best fits followed the sequence: Langmuir TI = Temkin > DR > LangmuirTII > Freundlich. The microporosity determined by adsorption of CO2 at 273 K with a single term DR regression presented R(2) > 0.98. The adsorption of acetaminophen may occur in specific sites and also in the basal region. It was determined that the adsorption process of acetaminophen on AC in SGF is spontaneous (ΔG <0) and exothermic (-ΔHads.). Moreover, the area occupied by the acetaminophen molecule was calculated with a relative error from 7.8 to 50%.

  2. Rapid onset of Stevens-Johnson syndrome and toxic epidermal necrolysis after ingestion of acetaminophen

    PubMed Central

    Kim, Eun-Jin; Lim, Hyun; Park, So Young; Kim, Sujeong; Yoon, Sun-Young; Bae, Yun-Jeong; Kwon, Hyouk-Soo; Cho, You Sook; Moon, Hee-Bom

    2014-01-01

    Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, but life-threatening, severe cutaneous adverse reactions most frequently caused by exposure to drugs. Several reports have associated the use of acetaminophen with the risk of SJS or TEN. A typical interval from the beginning of drug therapy to the onset of an adverse reaction is 1-3 weeks. A 43-year-old woman and a 60-year-old man developed skin lesions within 3 days after administration of acetaminophen for a 3-day period. Rapid identification of the symptoms of SJS and TEN caused by ingestion of acetaminophen enabled prompt withdrawal of the culprit drug. After administration of intravenous immunoglobulin G, both patients recovered fully and were discharged. These two cases of rapidly developed SJS/TEN after ingestion of acetaminophen highlight the possibility that these complications can develop within only a few days following ingestion of over-the-counter medications such as acetaminophen. PMID:24527413

  3. Acetaminophen-induced liver injury: Implications for temporal homeostasis of lipid metabolism and eicosanoid signaling pathway.

    PubMed

    Suciu, Maria; Gruia, Alexandra T; Nica, Dragos V; Azghadi, Seyed M R; Mic, Ani A; Mic, Felix A

    2015-12-05

    Acetaminophen is a commonly used drug that induces serious hepatotoxicity when overdosed, leading to increased levels of serum aminotransferases. However, little knowledge exists linking acetaminophen to liver free fatty acids and the eicosanoid-mediated signaling pathway. To this end, adult NMRI mice injected with a dose of 400 mg/kg acetaminophen were monitored for one week post-treatment. Consistent changes were observed in serum transaminases, profile of hepatic free fatty acids, expression of cyclooxygenase, elongase, lipogenesis, and lipolysis genes; as well as in expression patterns of cyclooxygenase-1 and -2 in the liver. Both linoleic acid and arachidonic acid--substrates in eicosanoid biosynthesis--were significantly influenced by overdose, and the latter peaked first among the free fatty acids examined here. There was a close similarity between the temporal dynamics of linoleic acid and aspartate aminotransferases. Moreover, serum transaminases were reduced by cyclooxygenase-2 inhibitors, but not by cyclooxygenase-1 inhibitors. Our results hence attest to the hazard of acetaminophen overdose on the temporal homeostasis of hepatic concentrations of free fatty acids and expression of key genes underlying liver lipid metabolism. There is also evidence for activation of a cyclooxygenase-mediated signaling pathway, especially the cyclooxygenase 2-prostanoid pathway, during acetaminophen-induced liver injury. Therefore, the results of the present study should provide valuable information to a wide audience, working to understand the health hazard of this drug and the implications of the eicosanoid signaling pathway in liver pathophysiology.

  4. Timescale analysis of a mathematical model of acetaminophen metabolism and toxicity.

    PubMed

    Reddyhoff, Dennis; Ward, John; Williams, Dominic; Regan, Sophie; Webb, Steven

    2015-12-07

    Acetaminophen is a widespread and commonly used painkiller all over the world. However, it can cause liver damage when taken in large doses or at repeated chronic doses. Current models of acetaminophen metabolism are complex, and limited to numerical investigation though provide results that represent clinical investigation well. We derive a mathematical model based on mass action laws aimed at capturing the main dynamics of acetaminophen metabolism, in particular the contrast between normal and overdose cases, whilst remaining simple enough for detailed mathematical analysis that can identify key parameters and quantify their role in liver toxicity. We use singular perturbation analysis to separate the different timescales describing the sequence of events in acetaminophen metabolism, systematically identifying which parameters dominate during each of the successive stages. Using this approach we determined, in terms of the model parameters, the critical dose between safe and overdose cases, timescales for exhaustion and regeneration of important cofactors for acetaminophen metabolism and total toxin accumulation as a fraction of initial dose.

  5. Enhancement of Antihyperalgesia by the Coadministration of N-palmitoylethanolamide and Acetaminophen in Diabetic Rats.

    PubMed

    Déciga-Campos, Myrna; Ortíz-Andrade, Rolffy

    2015-08-01

    Preclinical Research The objective of this study was to evaluate the pharmacological antihyperalgesic interaction between N-palmitoylethanolamide (PEA) and acetaminophen in diabetic rats using the formalin paw test. Streptozotocin (STZ)-induced diabetic rats received subcutaneous injections in the paw of PEA alone (1-100 μg/paw) or acetaminophen alone (3-300 μg/paw) 15 min before formalin (0.5%) injection. The results revealed concentration-dependent responses produced by PEA (EC50 = 7.19 ± 0.7 μg/paw) and acetaminophen (EC50 = 57.9 ± 1.9 μg/paw). Isobolographic analysis was used to evaluate the pharmacological interaction between the PEA + acetaminophen using the EC50 value and a fixed 1:1 ratio combination. The isobologram demonstrated that the combination investigated in this study produced a synergistic interaction; the experimental value (EC50 = 23.64 ± 1.9 μg/paw) was significantly smaller than those that resulted from theoretical calculations (EC50 = 32.56 μg/paw). These results provide evidence that PEA in combination with acetaminophen could be useful for pain therapy in neuropathic diabetic patients.

  6. Gene Expression in Rat Hearts Following Oral Administration of a Single Hepatotoxic Dose of Acetaminophen

    PubMed Central

    Kil, Hong Ryang; Park, Kwangsik; Noh, Chung Il

    2012-01-01

    Purpose Toxicity caused by acetaminophen and its toxic mechanisms in the liver have been widely studied, including effects involving metabolism and oxidative stress. However, its adverse effects on heart have not been sufficiently investigated. This study evaluated the cardiac influence and molecular events occurring within the myocardium in rats treated with a dose of acetaminophen large enough to induce conventional liver damage. Materials and Methods Male rats were orally administered a single dose of acetaminophen at 1,000 mg/kg-body weight, and subsequently examined for conventional toxicological parameters and for gene expression alterations to both the heart and liver 24 hours after administration. Results Following treatment, serum biochemical parameters including aspartate aminotransferase and alanine aminotransferase were elevated. Histopathological alterations of necrosis were observed in the liver, but not in the heart. However, alterations in gene expression were observed in both the liver and heart 24 hours after dosing. Transcriptional profiling revealed that acetaminophen changed the expression of genes implicated in oxidative stress, inflammatory processes, and apoptosis in the heart as well as in the liver. The numbers of up-regulated and down-regulated genes in the heart were 271 and 81, respectively, based on a two-fold criterion. Conclusion The induced expression of genes implicated in oxidative stress and inflammatory processes in the myocardium reflects molecular levels of injury caused by acetaminophen (APAP), which could not be identified by conventional histopathology. PMID:22187249

  7. Biowaiver monographs for immediate release solid oral dosage forms: acetaminophen (paracetamol).

    PubMed

    Kalantzi, L; Reppas, C; Dressman, J B; Amidon, G L; Junginger, H E; Midha, K K; Shah, V P; Stavchansky, S A; Barends, Dirk M

    2006-01-01

    Literature data are reviewed on the properties of acetaminophen (paracetamol) related to the biopharmaceutics classification system (BCS). According to the current BCS criteria, acetaminophen is BCS Class III compound. Differences in composition seldom, if ever, have an effect on the extent of absorption. However, some studies show differences in rate of absorption between brands and formulations. In particular, sodium bicarbonate, present in some drug products, was reported to give an increase in the rate of absorption, probably caused by an effect on gastric emptying. In view of Marketing Authorizations (MAs) given in a number of countries to acetaminophen drug products with rapid onset of action, it is concluded that differences in rate of absorption were considered therapeutically not relevant by the Health Authorities. Moreover, in view of its therapeutic use, its wide therapeutic index and its uncomplicated pharmacokinetic properties, in vitro dissolution data collected according to the relevant Guidances can be safely used for declaring bioequivalence (BE) of two acetaminophen formulations. Therefore, accepting a biowaiver for immediate release (IR) acetaminophen solid oral drug products is considered scientifically justified, if the test product contains only those excipients reported in this paper in their usual amounts and the test product is rapidly dissolving, as well as the test product fulfils the criterion of similarity of dissolution profiles to the reference product.

  8. Protective Effect of Acacia nilotica (L.) against Acetaminophen-Induced Hepatocellular Damage in Wistar Rats

    PubMed Central

    Kannan, Narayanan; Sakthivel, Kunnathur Murugesan; Guruvayoorappan, Chandrasekaran

    2013-01-01

    The potential biological functions of A. nilotica have long been described in traditional system of medicine. However, the protective effect of A. nilotica on acetaminophen-induced hepatotoxicity is still unknown. The present study attempted to investigate the protective effect of A. nilotica against acetaminophen-induced hepatic damage in Wistar rats. The biochemical liver functional tests Alanine transaminase (ALT), Aspartate transaminase (AST), Alkaline phosphatase (ALP), total bilirubin, total protein, oxidative stress test (Lipid peroxidation), antioxidant parameter glutathione (GSH), and histopathological changes were examined. Our results show that the pretreatment with A. nilotica (250 mg/kg·bw) orally revealed attenuation of serum activities of ALT, AST, ALP, liver weight, and total bilirubin levels that were enhanced by administration of acetaminophen. Further, pretreatment with extract elevated the total protein and GSH level and decreased the level of LPO. Histopathological analysis confirmed the alleviation of liver damage and reduced lesions caused by acetaminophen. The present study undoubtedly provides a proof that hepatoprotective action of A. nilotica extract may rely on its effect on reducing the oxidative stress in acetaminophen-induced hepatic damage in rat model. PMID:23864853

  9. Identification of a new metabolite of GHB: gamma-hydroxybutyric acid glucuronide.

    PubMed

    Petersen, Ida Nymann; Tortzen, Christian; Kristensen, Jesper Langgaard; Pedersen, Daniel Sejer; Breindahl, Torben

    2013-06-01

    Gamma-hydroxybutyric acid (GHB) is an important analyte in clinical and forensic toxicology with a narrow detection window of 3-6 h. In the search of improved detection methods, the existence in vivo of a glucuronated GHB metabolite (GHB-GLUC) was hypothesized. Chemically pure standards of GHB-GLUC and a deuterated analogue for chromatography were synthesized. Liquid chromatography and tandem mass spectrometry were used for targeted analysis in anonymous clinical urine samples (n = 50). GHB-GLUC was found in concentrations ranging from 0.11 to 5.0 µg/mL (mean: 1.3 ± 1.2 µg/mL). Thus far, this is the first report of a GHB glucuronide detected in biological samples. Given that glucuronides generally have longer half-life values than their corresponding free drugs, GHB-GLUC should theoretically be a biomarker of GHB intoxication. It is also proposed that the hitherto unexplained reports of elevated GHB concentrations in some biological samples, which has caused the setting of a relatively high cutoff value (10 µg/mL), represent total GHB measurements (sum of free GHB and actively chemically hydrolyzed GHB-GLUC). To address these challenges, the present study must be followed by comprehensive pharmacokinetic and stability studies after the controlled administration of GHB.

  10. Isolation and determination of benzo(a)pyrene glucuronide and sulfate conjugates in soybean leaves

    SciTech Connect

    Negishi, T.; Nakano, M.; Kobayashi, S.; Kim, C.H.

    1987-08-01

    BaP is metabolized in mammalian systems by the mixed function oxidase system of liver microsomes. This system catalyzes the oxidation of BaP via epoxide intermediate to phenol, diol and quinone metabolites. One of these 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydro-BaP is thought to act as the ultimate carcinogen by binding covalently to cellular DNA. It is also known that Cunninghamella elegans oxidized BaP to its phenol, diol and quinone metabolites. In addition, the alcohols were detected as glucuronide and sulfate conjugates. These metabolites are remarkably similar to those observed in higher organisms. On the other hand, some investigators have demonstrated that plants take up BaP and anthracene from soil or culture medium containing these compounds. This paper reports the finding that soybeans grown in BaP polluted soil take it up and metabolize to its phenol, diol and the glucuronide and sulfate conjugates of the alcohols.

  11. 99mTc-d-penicillamine-glucuronide: synthesis, radiolabeling, in vitro and in vivo evaluation.

    PubMed

    Teksöz, Serap; Içhedef, Ciğdem Acar; Ozyüncü, Seniha; Müftüler, Fazilet Zümrüt Biber; Unak, Perihan; Medine, Ilker Emin; Ertay, Türkan; Eren, Mine Şencan

    2011-10-01

    The current study was aimed at synthesizing a glucuronide derivative of D-penicillamine (D-PA) to be used for imaging purposes. First of all, D-PA-glucuronide (D-PA-Glu) was synthesized by experimental treatments starting with uridine 5'-diphospho-glucuronosyltransferase enzyme rich microsome preparate. Then, the synthesized compound was labeled with technetium ((99m)Tc) by using a reduction method with stannous chloride. Quality controls were performed by using high-performance liquid chromatography and thin-layer radio chromatography (TLRC). Radiolabeling yield of (99m)Tc-D-PA-Glu was more than 98% according to TLRC results. In vitro evaluations of radiolabeled complexes were investigated on PC-3 human prostate cancer cells. (99m)Tc-D-PA-Glu exhibited more accumulation on PC-3 cells versus (99m)Tc-D-PA at 240 minutes. In order to determine its radiopharmaceutical potential, biodistribution studies were carried out in male Albino Wistar rats. The biodistribution results of (99m)Tc-D-PA-Glu, showed the highest uptake in prostate at 120 minutes postinjection with the main excretion route being through kidneys and bladder. (99m)Tc-D-PA-Glu and (99m)Tc-D-PA have exhibited different biodistribution results.

  12. Identification of flunixin glucuronide and depletion of flunixin and its marker residue in bovine milk.

    PubMed

    Jedziniak, P; Olejnik, M; Szprengier-Juszkiewicz, T; Smulski, S; Kaczmarowski, M; Żmudzki, J

    2013-12-01

    Residues of flunixin [and its marker residue 5-hydroxyflunixin (5OHFLU)] were determined in milk from cows that intravenously received therapeutic doses of the drug. The samples were collected during each milking (every 12 h) for six consecutive days, and concentrations of flunixin and its metabolites were determined by the method with and without enzymatic hydrolysis (beta-glucuronidase). The highest flunixin concentration in milk was observed 12 h after dosing (2.4 ± 1.42 μg/kg, mean ± SD). Flunixin concentrations in the samples determined with enzymatic hydrolysis were significantly higher (P < 0.05), which suggests the transfer of flunixin glucuronide to the milk. Additionally, unambiguous identification of flunixin glucuronide in the bovine milk was performed with linear ion-trap mass spectrometry. The 5OHFLU concentrations analyzed without enzymatic hydrolysis (22.3 ± 16.04 μg/kg) were similar to this obtained with enzymatic hydrolysis. Flunixin and 5OHFLU concentrations dropped below the limits of detection at 48 h after last dosing.

  13. A newborn screening method for cerebrotendinous xanthomatosis using bile alcohol glucuronides and metabolite ratios.

    PubMed

    Vaz, Frédéric M; Bootsma, Albert H; Kulik, Willem; Verrips, Aad; Wevers, Ron A; Schielen, Peter C; DeBarber, Andrea E; Huidekoper, Hidde H

    2017-03-17

    Cerebrotendinous xanthomatosis (CTX) is a treatable neurodegenerative metabolic disorder of bile acid synthesis where symptoms can be prevented if treatment with chenodeoxycholic acid supplementation is initiated early in life, making CTX an excellent candidate for newborn screening. We developed a new dried blood spot screening assay for this disorder based on different ratios between the accumulating cholestanetetrol glucuronide (tetrol) and specific bile acids/bile acid intermediates, without the need for derivatization. A quarter-inch dried blood spot punch was extracted with methanol, internal standards were added and after concentration the extract was injected into the tandem mass spectrometer using a 2 minute flow injection analysis where specific transitions were measured for cholestanetetrol glucuronide, tauro-chenodeoxycholic acid (t-CDCA) and tauro-trihydroxycholestanoic acid (t-THCA). A proof of principle experiment was performed using 216 Guthrie cards from healthy term/preterm newborns, CTX patients and Zellweger patients. Using two calculated biomarkers, tetrol/t-CDCA and t-THCA/tetrol, this straightforward method achieved an excellent separation between dried blood spots of CTX patients and those of controls, Zellweger patients and newborns with cholestasis. The results of this small pilot study indicate that the tetrol/t-CDCA ratio is an excellent derived biomarker for CTX that has the potential to be used in neonatal screening programs.

  14. Synthesis and Antitumor Properties of BQC-Glucuronide, a Camptothecin Prodrug for Selective Tumor Activation.

    PubMed

    Prijovich, Zeljko M; Burnouf, Pierre-Alain; Chou, Hua-Cheng; Huang, Ping-Ting; Chen, Kai-Chuan; Cheng, Tian-Lu; Leu, Yu-Lin; Roffler, Steve R

    2016-04-04

    Major limitations of camptothecin anticancer drugs (toxicity, nonselectivity, water insolubility, inactivation by human serum albumin) may be improved by creating glucuronide prodrugs that rely on beta-glucuronidase for their activation. We found that the camptothecin derivative 5,6-dihydro-4H-benzo[de]quinoline-camptothecin (BQC) displays greater cytotoxicity against cancer cells than the clinically used camptothecin derivatives SN-38 and topotecan even in the presence of human serum albumin. We synthesized the prodrug BQC-glucuronide (BQC-G), which was 4000 times more water soluble and 20-40 times less cytotoxic than BQC. Importantly, even in the presence of human serum albumin, BQC-G was efficiently hydrolyzed by beta-glucuronidase and produced greater cytotoxicity (IC50 = 13 nM) than camptothecin, 9-aminocamptothecin, SN-38, or topotecan (IC50 > 3000, 1370, 48, and 28 nM, respectively). BQC-G treatment of mice bearing human colon cancer xenografts with naturally or artificially elevated beta-glucuronidase activity produced significant antitumor activity, showing that BQC-G is a potent prodrug suitable for selective intratumoral drug activation.

  15. Lophirones B and C Attenuate Acetaminophen-Induced Liver Damage in Mice: Studies on Hepatic, Oxidative Stress and Inflammatory Biomarkers.

    PubMed

    Ajiboye, Taofeek O

    2016-10-01

    Lophirones B and C are chalcone dimers with proven chemopreventive activity. This study evaluates the hepatoprotective effect lophirones B and C in acetaminophen-induced hepatic damage in mice using biomarkers of hepatocellular indices, oxidative stress, proinflammatory factors and lipid peroxidation. Oral administrations of lophirones B and C significantly (p < 0.05) attenuated acetaminophen-mediated alterations in serum alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, albumin and total bilirubin. Similarly, acetaminophen-mediated decrease in activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6- phosphate dehydrogenase were significantly attenuated in the liver of mice. Increased levels of conjugated dienes, lipid hydroperoxides, malondialdehyde, protein carbonyl and fragmented DNA were significantly lowered by lophirones B and C. Levels of tumour necrosis factor-α, interleukin-6 and 8 were significantly lowered in serum of acetaminophen treated mice by the chalcone dimers. Overall, results of this study show that lophirones B and C halted acetaminophen-mediated hepatotoxicity.

  16. Protection against acetaminophen-induced liver injury by allopurinol is dependent on aldehyde oxidase-mediated liver preconditioning

    SciTech Connect

    Williams, C. David; McGill, Mitchell R.; Lebofsky, Margitta; Bajt, Mary Lynn; Jaeschke, Hartmut

    2014-02-01

    Acetaminophen (APAP) overdose causes severe and occasionally fatal liver injury. Numerous drugs that attenuate APAP toxicity have been described. However these compounds frequently protect by cytochrome P450 inhibition, thereby preventing the initiating step of toxicity. We have previously shown that pretreatment with allopurinol can effectively protect against APAP toxicity, but the mechanism remains unclear. In the current study, C3HeB/FeJ mice were administered allopurinol 18 h or 1 h prior to an APAP overdose. Administration of allopurinol 18 h prior to APAP overdose resulted in an 88% reduction in liver injury (serum ALT) 6 h after APAP; however, 1 h pretreatment offered no protection. APAP-cysteine adducts and glutathione depletion kinetics were similar with or without allopurinol pretreatment. The phosphorylation and mitochondrial translocation of c-jun-N-terminal-kinase (JNK) have been implicated in the progression of APAP toxicity. In our study we showed equivalent early JNK activation (2 h) however late JNK activation (6 h) was attenuated in allopurinol treated mice, which suggests that later JNK activation is more critical for the toxicity. Additional mice were administered oxypurinol (primary metabolite of allopurinol) 18 h or 1 h pre-APAP, but neither treatment protected. This finding implicated an aldehyde oxidase (AO)-mediated metabolism of allopurinol, so mice were treated with hydralazine to inhibit AO prior to allopurinol/APAP administration, which eliminated the protective effects of allopurinol. We evaluated potential targets of AO-mediated preconditioning and found increased hepatic metallothionein 18 h post-allopurinol. These data show metabolism of allopurinol occurring independent of P450 isoenzymes preconditions the liver and renders the animal less susceptible to an APAP overdose. - Highlights: • 18 h allopurinol pretreatment protects against acetaminophen-induced liver injury. • 1 h allopurinol pretreatment does not protect from APAP

  17. Baicalin Attenuates IL-17-Mediated Acetaminophen-Induced Liver Injury in a Mouse Model

    PubMed Central

    Liao, Chia-Chih; Day, Yuan-Ji; Lee, Hung-Chen; Liou, Jiin-Tarng; Chou, An-Hsun; Liu, Fu-Chao

    2016-01-01

    Background IL-17 has been shown to be involved in liver inflammatory disorders in both mice and humans. Baicalin (BA), a major compound extracted from traditional herb medicine (Scutellariae radix), has potent hepatoprotective properties. Previous study showed that BA inhibits IL-17-mediated lymphocyte adhesion and downregulates joint inflammation. The aim of this study is to investigate the role of IL-17 in the hepatoprotective effects of BA in an acetaminophen (APAP)-induced liver injury mouse model. Methods Eight weeks male C57BL/6 (B6) mice were used for this study. Mice received intraperitoneal hepatotoxic injection of APAP (300 mg/kg) and after 30 min of injection, the mice were treated with BA at a concentration of 30 mg/kg. After 16 h of treatment, mice were killed. Blood samples and liver tissues were harvested for analysis of liver injury parameters. Results APAP overdose significantly increased the serum alanine transferase (ALT) levels, hepatic activities of myeloperoxidase (MPO), expression of cytokines (TNF-α, IL-6, and IL-17), and malondialdehyde (MDA) activity when compared with the control animals. BA treatment after APAP administration significantly attenuated the elevation of these parameters in APAP-induced liver injury mice. Furthermore, BA treatment could also decrease hepatic IL-17-producing γδT cells recruitment, which was induced after APAP overdose. Conclusion Our data suggested that baicalin treatment could effectively decrease APAP-induced liver injury in part through attenuation of hepatic IL-17 expression. These results indicate that baicalin is a potential hepatoprotective agent. PMID:27855209

  18. Activation of GR but not PXR by dexamethasone attenuated acetaminophen hepatotoxicities via Fgf21 induction.

    PubMed

    Vispute, Saurabh G; Bu, Pengli; Le, Yuan; Cheng, Xingguo

    2017-03-01

    Glucocorticoid receptor (GR) signaling is indispensable for cell growth and development, and plays important roles in drug metabolism. Fibroblast growth factor (Fgf) 21, an important regulator of glucose, lipid, and energy metabolism, plays a cytoprotective role by attenuating toxicities induced by chemicals such as dioxins, acetaminophen (APAP), and alcohols. The present study investigates the impact of dexamethasone (DEX)-activated GR on Fgf21 expression and how it affects the progression of APAP-induced hepatotoxicity. Our results showed that DEX dose/concentration- and time-dependently increased Fgf21 mRNA and protein expression in mouse liver as well as cultured mouse and human hepatoma cells. By using PXR-null mouse model, we demonstrated that DEX induced Fgf21 expression by a PXR-independent mechanism. In cultured mouse and human hepatoma cells, inhibition of GR signaling, by RU486 (Mifepristone) or GR silencing using GR-specific siRNA, attenuated DEX-induced Fgf21 expression. In addition, DEX increased luciferase reporter activity driven by the 3.0-kb mouse and human Fgf21/FGF21 gene promoter. Further, ChIP-qPCR assays demonstrated that DEX increased the binding of GR to the specific cis-regulatory elements located in the 3.0-kb mouse and human Fgf21/FGF21 gene promoter. Pretreatment of 2mg/kg DEX ameliorated APAP-induced liver injury in wild-type but not Fgf21-null mice. In conclusion, via GR activation, DEX induced Fgf21 expression in mouse liver and human hepatoma cells.

  19. Protective effects of acetaminophen on ibuprofen-induced gastric mucosal damage in rats with associated suppression of matrix metalloproteinase.

    PubMed

    Fukushima, Eriko; Monoi, Noriyuki; Mikoshiba, Shigeo; Hirayama, Yutaka; Serizawa, Tetsushi; Adachi, Kiyo; Koide, Misao; Ohdera, Motoyasu; Murakoshi, Michiaki; Kato, Hisanori

    2014-04-01

    Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to cause gastric mucosal damage as a side effect. Acetaminophen, widely used as an analgesic and antipyretic drug, has gastroprotective effects against gastric lesions induced by absolute ethanol and certain NSAIDs. However, the mechanisms that underlie the gastroprotective effects of acetaminophen have not yet been clarified. In the present study, we examined the role and protective mechanism of acetaminophen on ibuprofen-induced gastric damage in rats. Ibuprofen and acetaminophen were administered orally, and the gastric mucosa was macroscopically examined 4 hours later. Acetaminophen decreased ibuprofen-induced gastric damage in a dose-dependent manner. To investigate the mechanisms involved, transcriptome analyses of the ibuprofen-damaged gastric mucosa were performed in the presence and absence of acetaminophen. Ingenuity pathway analysis (IPA) software revealed that acetaminophen suppressed the pathways related to cellular assembly and inflammation, whereas they were highly activated by ibuprofen. On the basis of gene classifications from the IPA Knowledge Base, we identified the following five genes that were related to gastric damage and showed significant changes in gene expression: interleukin-1β (IL-1β), chemokine (C-C motif) ligand 2 (CCL2), matrix metalloproteinase-10 (MMP-10), MMP-13, and FBJ osteosarcoma oncogene (FOS). Expression of these salient genes was confirmed using real-time polymerase chain reaction. The expression of MMP-13 was the most reactive to the treatments, showing strong induction by ibuprofen and suppression by acetaminophen. Moreover, MMP-13 inhibitors decreased ibuprofen-induced gastric damage. In conclusion, these results suggest that acetaminophen decreases ibuprofen-induced gastric mucosal damage and that the suppression of MMP-13 may play an important role in the gastroprotective effects of acetaminophen.

  20. Diallyl disulfide attenuates acetaminophen-induced renal injury in rats

    PubMed Central

    Shin, Jin-Young; Han, Ji-Hee; Ko, Je-Won; Park, Sung-Hyeuk; Shin, Na-Rae; Jung, Tae-Yang; Kim, Hyun-A; Kim, Sung-Hwan; Shin, In-Sik

    2016-01-01

    This study investigated the protective effects of diallyl disulfide (DADS) against acetaminophen (AAP)-induced acute renal injury in male rats. We also investigated the effects of DADS on kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), which are novel biomarkers of nephrotoxicity in renal tissues, in response to AAP treatment. The following four experimental groups were evaluated: (1) vehicle control, (2) AAP (1,000 mg/kg), (3) AAP&DADS, and (4) DADS (50 mg/kg/day). AAP treatment caused acute kidney injury evidenced by increased serum blood urea nitrogen (BUN) levels and histopathological alterations. Additionally, Western blot and immunohistochemistry analysis showed increased expression of KIM-1 and NGAL proteins in renal tissues of AAP-treated rats. In contrast, DADS pretreatment significantly attenuated the AAP-induced nephrotoxic effects, including serum BUN level and expression of KIM-1 and NGAL proteins. Histopathological studies confirmed the renoprotective effect of DADS. The results suggest that DADS prevents AAP-induced acute nephrotoxicity, and that KIM-1 and NGAL may be useful biomarkers for the detection and monitoring of acute kidney injury associated with AAP exposure. PMID:28053613

  1. Diallyl disulfide attenuates acetaminophen-induced renal injury in rats.

    PubMed

    Shin, Jin-Young; Han, Ji-Hee; Ko, Je-Won; Park, Sung-Hyeuk; Shin, Na-Rae; Jung, Tae-Yang; Kim, Hyun-A; Kim, Sung-Hwan; Shin, In-Sik; Kim, Jong-Choon

    2016-12-01

    This study investigated the protective effects of diallyl disulfide (DADS) against acetaminophen (AAP)-induced acute renal injury in male rats. We also investigated the effects of DADS on kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL), which are novel biomarkers of nephrotoxicity in renal tissues, in response to AAP treatment. The following four experimental groups were evaluated: (1) vehicle control, (2) AAP (1,000 mg/kg), (3) AAP&DADS, and (4) DADS (50 mg/kg/day). AAP treatment caused acute kidney injury evidenced by increased serum blood urea nitrogen (BUN) levels and histopathological alterations. Additionally, Western blot and immunohistochemistry analysis showed increased expression of KIM-1 and NGAL proteins in renal tissues of AAP-treated rats. In contrast, DADS pretreatment significantly attenuated the AAP-induced nephrotoxic effects, including serum BUN level and expression of KIM-1 and NGAL proteins. Histopathological studies confirmed the renoprotective effect of DADS. The results suggest that DADS prevents AAP-induced acute nephrotoxicity, and that KIM-1 and NGAL may be useful biomarkers for the detection and monitoring of acute kidney injury associated with AAP exposure.

  2. Characterization of acetaminophen-induced cytotoxicity in target tissues

    PubMed Central

    Guo, Chao; Xie, Guojie; Su, Min; Wu, Xinmou; Lu, Xiuli; Wu, Ka; Wei, Chaohe

    2016-01-01

    Acetaminophen (APAP), commonly used in clinical prescription, has time- and dose-dependent side effects. Thus, further animal study warrants to be investigated to assess possible adverse effect of APAP application. Here, we conducted pre-clinical research to elucidate the molecular mechanism regarding APAP-mediated toxicological action. Our data showed that serous/urinary and hepatic/renal APAP concentrations were significantly increased when compared with normal control, which the liver tissue showed the highest level. As an acute liver damage model induced by APAP, absolute liver weight, serum enzyme (ALT), urine protein content were notably elevated. Representatively, APAP-damaged liver resulted in increased pro-apoptotic Bax and compensatory Ki-67 positive cells, while the number of anti-apoptotic Bcl2 positive cells was reduced. In addition, the immunoactivity markers for NF-κB, TRL4, TNF-α in the kidney were increased, respectively. Furthermore, intracellular TRL4 and TNF-α mRNAs in the liver and kidney showed significant up-regulation. In summary, our current findings demonstrate that APAP-mediated the specific cytotoxicity is linked to the molecular mechanisms of facilitating apoptosis and inflammatory stress in the liver and kidney. PMID:27830028

  3. Effects of erdosteine on acetaminophen-induced hepatotoxicity in rats.

    PubMed

    Kuvandik, Guven; Duru, Mehmet; Nacar, Ahmet; Yonden, Zafer; Helvaci, Rami; Koc, Ahmet; Kozlu, Tolunay; Kaya, Hasan; Sogüt, Sadik

    2008-07-01

    We investigated the effects of erdosteine on acetaminophen (APAP)-induced hepatotoxicity in rats. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), AST (aspartate aminotransferase), and ALT (alanine transaminase) activities, and malonyldialdehyde (MDA) and nitric oxide levels as oxidant/antioxidant biochemical parameters were investigated with light microscopic evaluation in adult female Wistar Albino rats. APAP administration produced a decrease in hepatic SOD, CAT, and GSH-Px activities, and coadministration of erdosteine (150 and 300 mg/kg) resulted in increases in the activities. MDA and NO levels increased in the APAP group, and erdosteine treatments prevented these increases. Significant elevations in serum AST and ALT levels were observed in the APAP group, and when erdosteine and APAP were coadministered, their serum levels were close to those in the control group. Light microscopic evaluation of livers showed that there were remarkable centrilobular (zone III) hepatic necrosis and mild to moderate sinusoidal congestion in the APAP group, whereas in the erdosteine group, cellular necrosis was minimal and the hepatocytes maintained a better morphology when compared to the APAP group. Erdosteine prevented APAP-induced liver injury and toxic side effects probably through the antioxidant and radical scavenging effects of erdosteine.

  4. Evaluation of Hepatoprotective Activity of Adansonia digitata Extract on Acetaminophen-Induced Hepatotoxicity in Rats

    PubMed Central

    Hanafy, Abeer; Aldawsari, Hibah M.; Badr, Jihan M.; Ibrahim, Amany K.; Abdel-Hady, Seham El-Sayed

    2016-01-01

    The methanol extract of the fruit pulp of Adansonia digitata L. (Malvaceae) was examined for its hepatoprotective activity against liver damage induced by acetaminophen in rats. The principle depends on the fact that administration of acetaminophen will be associated with development of oxidative stress. In addition, hepatospecific serum markers will be disturbed. Treatment of the rats with the methanol extract of the fruit pulp of Adansonia digitata L. prior to administration of acetaminophen significantly reduced the disturbance in liver function. Liver functions were measured by assessment of total protein, total bilirubin, ALP, ALT, and AST. Oxidative stress parameter and antioxidant markers were also evaluated. Moreover, histopathological evaluation was performed in order to assess liver case regarding inflammatory infiltration or necrosis. Animals were observed for any symptoms of toxicity after administration of extract of the fruit pulp of Adansonia digitata L. to ensure safety of the fruit extract. PMID:27118980

  5. Evaluation of Hepatoprotective Activity of Adansonia digitata Extract on Acetaminophen-Induced Hepatotoxicity in Rats.

    PubMed

    Hanafy, Abeer; Aldawsari, Hibah M; Badr, Jihan M; Ibrahim, Amany K; Abdel-Hady, Seham El-Sayed

    2016-01-01

    The methanol extract of the fruit pulp of Adansonia digitata L. (Malvaceae) was examined for its hepatoprotective activity against liver damage induced by acetaminophen in rats. The principle depends on the fact that administration of acetaminophen will be associated with development of oxidative stress. In addition, hepatospecific serum markers will be disturbed. Treatment of the rats with the methanol extract of the fruit pulp of Adansonia digitata L. prior to administration of acetaminophen significantly reduced the disturbance in liver function. Liver functions were measured by assessment of total protein, total bilirubin, ALP, ALT, and AST. Oxidative stress parameter and antioxidant markers were also evaluated. Moreover, histopathological evaluation was performed in order to assess liver case regarding inflammatory infiltration or necrosis. Animals were observed for any symptoms of toxicity after administration of extract of the fruit pulp of Adansonia digitata L. to ensure safety of the fruit extract.

  6. A rationale for combining acetaminophen and NSAIDs for mild-to-moderate pain.

    PubMed

    Altman, R D

    2004-01-01

    Analgesic therapy that combines individual agents with different mechanisms of action has potential advantages for the management of mild-to-moderate pain in the outpatient setting. Theoretically, this approach can lead to greater efficacy and fewer adverse events. While the precise mechanism of action for the analgesic effect of acetaminophen remains uncertain, accumulating evidence suggests that its activity resides primarily in the central nervous system. In contrast, the site of action for the analgesic effect of nonsteroidal anti-inflammatory drugs (NSAIDs) is predominantly peripheral, within injured or inflamed tissue. Several controlled clinical studies among patients with musculoskeletal conditions, dental pain, or postoperative pain have shown that combinations of acetaminophen and NSAIDs provide additive pain-relieving activity, thereby leading to dose-sparing effects and improved safety. Further studies are warranted to determine the clinical utility and safety of acetaminophen/NSAID combinations as analgesic therapy for common conditions associated with mild-to-moderate pain.

  7. Carbon based electrodes modified with horseradish peroxidase immobilized in conducting polymers for acetaminophen analysis.

    PubMed

    Tertis, Mihaela; Florea, Anca; Sandulescu, Robert; Cristea, Cecilia

    2013-04-11

    The development and optimization of new biosensors with horseradish peroxidase immobilized in carbon nanotubes-polyethyleneimine or polypyrrole nanocomposite film at the surface of two types of transducer is described. The amperometric detection of acetaminophen was carried out at -0.2 V versus Ag/AgCl using carbon based-screen printed electrodes (SPEs) and glassy carbon electrodes (GCEs) as transducers. The electroanalytical parameters of the biosensors are highly dependent on their configuration and on the dimensions of the carbon nanotubes. The best limit of detection obtained for acetaminophen was 1.36 ± 0.013 μM and the linear range 9.99-79.01 μM for the HRP-SWCNT/PEI in GCE configuration. The biosensors were successfully applied for the detection of acetaminophen in several drug formulations.

  8. Antioxidant and hepatoprotective effects of punicalagin and punicalin on acetaminophen-induced liver damage in rats.

    PubMed

    Lin, C C; Hsu, Y F; Lin, T C; Hsu, H Y

    2001-05-01

    Punicalagin and punicalin were isolated from the leaves of Terminalia catappa L., a Combretaceous plant distributed throughout tropical and subtropical beaches, which is used for the treatment of dermatitis and hepatitis. Our previous studies showed that both of these compounds exert antioxidative activity. In this study, the antihepatotoxic activity of punicalagin and punicalin on acetaminophen-induced toxicity in the rat liver was evaluated. After evaluating the changes of several biochemical functions in serum, the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were increased by acetaminophen administration and reduced by punicalagin and punicalin. Histological changes around the hepatic central vein and oxidative damage induced by acetaminophen were also recovered by both compounds. The data show that both punicalagin and punicalin exert antihepatotoxic activity, but treatment with larger doses enhanced liver damage. These results suggest that even if punicalagin and punicalin have antioxidant activity at small doses, treatment with larger doses will possibly induce some cell toxicities.

  9. Carbon Based Electrodes Modified with Horseradish Peroxidase Immobilized in Conducting Polymers for Acetaminophen Analysis

    PubMed Central

    Tertis, Mihaela; Florea, Anca; Sandulescu, Robert; Cristea, Cecilia

    2013-01-01

    The development and optimization of new biosensors with horseradish peroxidase immobilized in carbon nanotubes-polyethyleneimine or polypyrrole nanocomposite film at the surface of two types of transducer is described. The amperometric detection of acetaminophen was carried out at −0.2 V versus Ag/AgCl using carbon based-screen printed electrodes (SPEs) and glassy carbon electrodes (GCEs) as transducers. The electroanalytical parameters of the biosensors are highly dependent on their configuration and on the dimensions of the carbon nanotubes. The best limit of detection obtained for acetaminophen was 1.36 ± 0.013 μM and the linear range 9.99–79.01 μM for the HRP-SWCNT/PEI in GCE configuration. The biosensors were successfully applied for the detection of acetaminophen in several drug formulations. PMID:23580052

  10. Efflux Transport Characterization of Resveratrol Glucuronides in UDP-Glucuronosyltransferase 1A1 Transfected HeLa Cells: Application of a Cellular Pharmacokinetic Model to Decipher the Contribution of Multidrug Resistance-Associated Protein 4.

    PubMed

    Wang, Shuai; Li, Feng; Quan, Enxi; Dong, Dong; Wu, Baojian

    2016-04-01

    Resveratrol undergoes extensive metabolism to form biologically active glucuronides in humans. However, the transport mechanisms for resveratrol glucuronides are not fully established. Here, we aimed to characterize the efflux transport of resveratrol glucuronides using UGT1A1-overexpressing HeLa cells (HeLa1A1 cells), and to determine the contribution of multidrug resistance-associated protein (MRP) 4 to cellular excretion of the glucuronides. Two glucuronide isomers [i.e., resveratrol 3-O-glucuronide (R3G) and resveratrol 4'-O-glucuronide (R4'G)] were excreted into the extracellular compartment after incubation of resveratrol (1-100 μM) with HeLa1A1 cells. The excretion rate was linearly related to the level of intracellular glucuronide, indicating that glucuronide efflux was a nonsaturable process. MK-571 (a dual inhibitor of UGT1A1 and MRPs) significantly decreased the excretion rates of R3G and R4'G while increasing their intracellular levels. Likewise, short-hairpin RNA (shRNA)-mediated silencing of MRP4 caused a significant reduction in glucuronide excretion but an elevation in glucuronide accumulation. Furthermore, β-glucuronidase expressed in the cells catalyzed the hydrolysis of the glucuronides back to the parent compound. A cellular pharmacokinetic model integrating resveratrol transport/metabolism with glucuronide hydrolysis/excretion was well fitted to the experimental data, allowing derivation of the efflux rate constant values in the absence or presence of shRNA targeting MRP4. It was found that a large percentage of glucuronide excretion (43%-46%) was attributed to MRP4. In conclusion, MRP4 participated in cellular excretion of R3G and R4'G. Integration of mechanistic pharmacokinetic modeling with transporter knockdown was a useful method to derive the contribution percentage of an exporter to overall glucuronide excretion.

  11. Fulminate Hepatic Failure in a 5 Year Old Female after Inappropriate Acetaminophen Treatment

    PubMed Central

    Kasmi, Irena; Sallabanda, Sashenka; Kasmi, Gentian

    2015-01-01

    BACKGROUND: Acetaminophen is a drug widely used in children because of its safety and efficacy. Although the risk of its toxicity is lower in children such reactions occur in pediatric patients from intentional overdoses and less frequently attributable to unintended inappropriate dosing. The aim of reporting this case is to attract the attention to the risk of the acetaminophen toxicity when administered in high doses. CASE PRESENTATION: We report here a 5 year old girl who developed fulminate liver failure with renal impairment and acute pancreatitis, as a result of acetaminophen toxicity caused from unintentional repeated supratherapeutic ingestion, with a total administered dose of 4800 mg in three consecutive days, 1600 mg/day, approximately 90 mg/kg/day. The blood level of acetaminophen after 10 hours of the last administered dose was 32 mg/l. The patient presented with high fever, jaundice, lethargic, agitating with abdominal pain accompanied by encephalopathy. The liver function test revealed with high level of alanine aminotransferase 5794 UI/l and aspartate aminotransferase 6000 UI/l. Early initiation of oral N-acetylcysteine (NAC) after biochemical evidence of liver toxicity was beneficial with rapid improvement of liver enzymes, hepatic function and encephalopathy. During the course of the illness the child developed acute pancreatitis with hyperamylasemia 255 UI/L and hyperlypasemia 514 UI/L. Patient totally recovered within 29 days. CONCLUSION: Healthcare providers should considered probable acetaminophen toxicity in any child who has received the drug and presented with liver failure. When there is a high index of suspicion of acetaminophen toxicity NAC should be initiated and continued until there are no signs of hepatic dysfunction. PMID:27275268

  12. Acute liver failure following cleft palate repair: a case of therapeutic acetaminophen toxicity.

    PubMed

    Iorio, Matthew L; Cheerharan, Meera; Kaufman, Stuart S; Reece-Stremtan, Sarah; Boyajian, Michael

    2013-11-01

    Background : Acetaminophen is a widely used analgesic and antipyretic agent in the pediatric population. While the hepatotoxic effects of the drug have been well recognized in cases of acute overdose and chronic supratherapeutic doses, the toxic effects of acetaminophen are rarely documented in cases where therapeutic guidelines are followed. Case : An 8-month-old boy underwent cleft palate repair and placement of bilateral myringotomy tubes. His anesthetic course was uneventful, consisting of maintenance with desflurane and fentanyl. He received acetaminophen for routine postoperative pain management and was tolerating liquids and discharged home on postoperative day 1. On day 3, the child was profoundly lethargic with multiple episodes of emesis and was taken to the emergency department. He suffered a 45-second tonic-clonic seizure in transport to the regional children's medical center, and initial laboratory results demonstrated acute hepatitis with AST 24,424 U/L, ALT 12,885 U/L, total bilirubin 3.1 mg/dL, and a serum acetaminophen level of 83 μg/mL. Aggressive supportive measures including blood products and periprocedural fresh frozen plasma, piperacillin/tazobactam, and intravenous infusions of N-acetylcysteine, sodium phenylacetate and sodium benzoate, carnitine, and citrulline were administered. His metabolic acidosis and acute hepatitis began to correct by day 4, and he was discharged home without further surgical intervention on day 15. Conclusion : Although acetaminophen is an effective and commonly used analgesic in pediatric practice, hepatotoxicity is a potentially devastating complication. This report challenges the appropriateness of existing guidelines for acetaminophen administration and emphasizes the importance of close follow-up and hydration after even relatively minor surgery.

  13. High-Throughput LC-MS/MS Method for Direct Quantification of Glucuronidated, Sulfated, and Free Enterolactone in Human Plasma.

    PubMed

    Nørskov, Natalja P; Kyrø, Cecilie; Olsen, Anja; Tjønneland, Anne; Knudsen, Knud Erik Bach

    2016-03-04

    Sulfation and glucuronidation constitute a major pathway in humans and may play an important role in biological activity of metabolites including the enterolignan, enterolactone. Because the aromatic structure of enterolactone has similarities to steroid metabolites, it was hypothesized that enterolactone may protect against hormone-dependent cancers. This led to numerous epidemiological studies. In this context, there has been a demand for rapid, sensitive, high-throughput methods to measure enterolactone in biofluids. Different methods have been developed using GC-MS, HPLC, LC-MS/MS and a fluoroimmunoassay; however, most of these methods measure the total concentration of enterolactone, without any specification of its conjugation pattern. Here for the first time we present a high-throughput LC-MS/MS method to quantify enterolactone in its intact form as glucuronide, sulfate, and free enterolactone. The method has shown good accuracy and precision at low concentration and very high sensitivity, with LLOQ for enterolactone sulfate at 16 pM, enterolactone glucuronide at 26 pM, and free enterolactone at 86 pM. The short run time of 2.6 min combined with simple sample clean up and high sensitivity make this method attractive for the high-throughput of samples needed for epidemiological studies. Finally, we have adapted the new method to quantify enterolactone and its conjugates in 3956 plasma samples from an epidemiological study. We found enterolactone glucuronide to be the major conjugation form and that conjugation pattern was similar between men and women.

  14. N(+)-glucuronidation of aliphatic tertiary amines, a general phenomenon in the metabolism of H1-antihistamines in humans.

    PubMed

    Luo, H; Hawes, E M; McKay, G; Korchinski, E D; Midha, K K

    1991-10-01

    1. Representative drugs of the various structural classes of H1 antihistamines were chosen for study. The drugs chosen (class name in parentheses) were chlorpheniramine maleate and pheniramine maleate (alkylamines), diphenhydramine hydrochloride and doxylamine succinate (ethanolamines), pyrilamine maleate and tripelennamine hydrochloride (ethylenediamines), promethazine hydrochloride (phenothiazine), cyclizine lactate (piperazine) and terfenadine (miscellaneous). In each case oral dose(s) were administered over no more than 6 h to two healthy volunteers and the total urine collected for 36 h. 2. Metabolites from urine were separated by h.p.l.c. and individually collected prior to mass spectrometric analysis in the fast atom bombardment mode. The structure of each metabolite identified as a quaternary ammonium-linked glucuronide metabolite was confirmed by direct comparison of its mass spectrum and chromatographic behaviour with that of a synthetic authentic compound. 3. For eight of the nine drugs studied, metabolism by the N(+)-glucuronidation pathway was observed in each of the volunteers. Terfenadine was the exception. 4. The amount of each N(+)-glucuronide in the urine was estimated by h.p.l.c. analysis. The mean proportion of dose excreted as the metabolite was 14.3%, 6.5% and 4.0% for cyclizine, tripelennamine and diphenhydramine, respectively. Promethazine was the only case where the N(+)-glucuronide accounted for less than 1.0% of the administered dose in both volunteers examined.

  15. Human and Rat ABC Transporter Efflux of Bisphenol A and Bisphenol A Glucuronide: Interspecies Comparison and Implications for Pharmacokinetic Assessment

    EPA Science Inventory

    Significant interspecies differences exist between human and rodent with respect to absorption, distribution, and excretion of bisphenol A (BPA) and its primary metabolite, BPA-glucuronide (BPA-G). ATP-Binding Cassette (ABC) transporter enzymes play important roles in these physi...

  16. Crystallization of acetaminophen form II by plastic-ball-assisted ultrasonic irradiation

    NASA Astrophysics Data System (ADS)

    Mori, Yoichiro; Maruyama, Mihoko; Takahashi, Yoshinori; Yoshikawa, Hiroshi Y.; Okada, Shino; Adachi, Hiroaki; Sugiyama, Shigeru; Takano, Kazufumi; Murakami, Satoshi; Matsumura, Hiroyoshi; Inoue, Tsuyoshi; Yoshimura, Masashi; Mori, Yusuke

    2017-02-01

    We report a novel method for crystallizing the metastable polymorph form II of acetaminophen by using a plastic ball during ultrasonic irradiation. The presence of a plastic ball during ultrasonic irradiation of aqueous acetaminophen solution effectively increased the probability and reduced the induction time of form II crystallization. This method facilitated both laboratory- and large-scale production of form II crystals. Our method has significant advantages for practical application of form II because it can reduce the time to production and enable large-scale production.

  17. Electrochemical sensors based on carbon nanomaterials for acetaminophen detection: A review.

    PubMed

    Cernat, Andreea; Tertiş, Mihaela; Săndulescu, Robert; Bedioui, Fethi; Cristea, Alexandru; Cristea, Cecilia

    2015-07-30

    This study describes the advancements made over the last five years in the development of electrochemical sensors and biosensors for acetaminophen detection. This study reviews the different configurations based on unmodified and chemically modified carbon nanotubes and graphene. The influence of various modifiers on the two types of materials is presented along with their role on the enhancement of the selectivity and sensitivity of (bio)sensors. The review is focused on a comparative description of the applications of carbon-based nanomaterials towards acetaminophen detection and presents the results in a critical manner.

  18. Reversed-phase HPLC method for the estimation of acetaminophen, ibuprofen and chlorzoxazone in formulations.

    PubMed

    Ravisankar, S; Vasudevan, M; Gandhimathi, M; Suresh, B

    1998-08-01

    A simple, precise and rapid reversed-phase HPLC method was developed for the simultaneous estimation of acetaminophen, ibuprofen and chlorzoxazone in formulations. The method was carried out on a Kromasil(R) C(8) column using a mixture of 0.2% triethylamine:acetonitrile (adjusted to pH 3.2 using dilute orthophosphoric acid), and detection was carried out at 215 nm using ketoprofen as internal standard. All these drugs showed linearity in the range of 2-10 mug ml(-1), and limits of quantification was found to be 10, 50 and 20 ng ml(-1) for acetaminophen, ibuprofen and chlorzoxazone, respectively.

  19. Hemizygosity of transsulfuration genes confers increased vulnerability against acetaminophen-induced hepatotoxicity in mice

    SciTech Connect

    Hagiya, Yoshifumi; Kamata, Shotaro; Mitsuoka, Saya; Okada, Norihiko; Yoshida, Saori; Yamamoto, Junya; Ohkubo, Rika; Abiko, Yumi; Yamada, Hidenori; Akahoshi, Noriyuki; Kasahara, Tadashi; Kumagai, Yoshito; Ishii, Isao

    2015-01-15

    The key mechanism for acetaminophen hepatotoxicity is cytochrome P450 (CYP)-dependent formation of N-acetyl-p-benzoquinone imine, a potent electrophile that forms protein adducts. Previous studies revealed the fundamental role of glutathione, which binds to and detoxifies N-acetyl-p-benzoquinone imine. Glutathione is synthesized from cysteine in the liver, and N-acetylcysteine is used as a sole antidote for acetaminophen poisoning. Here, we evaluated the potential roles of transsulfuration enzymes essential for cysteine biosynthesis, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH), in acetaminophen hepatotoxicity using hemizygous (Cbs{sup +/−} or Cth{sup +/−}) and homozygous (Cth{sup −/−}) knockout mice. At 4 h after intraperitoneal acetaminophen injection, serum alanine aminotransferase levels were highly elevated in Cth{sup −/−} mice at 150 mg/kg dose, and also in Cbs{sup +/−} or Cth{sup +/−} mice at 250 mg/kg dose, which was associated with characteristic centrilobular hepatocyte oncosis. Hepatic glutathione was depleted while serum malondialdehyde accumulated in acetaminophen-injected Cth{sup −/−} mice but not wild-type mice, although glutamate–cysteine ligase (composed of catalytic [GCLC] and modifier [GCLM] subunits) became more activated in the livers of Cth{sup −/−} mice with lower K{sub m} values for Cys and Glu. Proteome analysis using fluorescent two-dimensional difference gel electrophoresis revealed 47 differentially expressed proteins after injection of 150 mg acetaminophen/kg into Cth{sup −/−} mice; the profiles were similar to 1000 mg acetaminophen/kg-treated wild-type mice. The prevalence of Cbs or Cth hemizygosity is estimated to be 1:200–300 population; therefore, the deletion or polymorphism of either transsulfuration gene may underlie idiosyncratic acetaminophen vulnerability along with the differences in Cyp, Gclc, and Gclm gene activities. - Highlights: • Cbs{sup +/−}, Cth{sup +/−}, and

  20. Evaluation of UGT protein interactions in human hepatocytes: Effect of siRNA down regulation of UGT1A9 and UGT2B7 on propofol glucuronidation in human hepatocytes☆

    PubMed Central

    Konopnicki, Camille M.; Dickmann, Leslie J.; Tracy, Jeffrey M.; Tukey, Robert H.; Wienkers, Larry C.; Foti, Robert S.

    2014-01-01

    Previous experiments performed in recombinant systems have suggested that protein–protein interactions occur between the UGTs and may play a significant role in modulating enzyme activity. However, evidence of UGT protein–protein interactions either in vivo or in more physiologically relevant in vitro systems has yet to be demonstrated. In this study, we examined oligomerization and its ability to affect glucuronidation in plated human hepatocytes. siRNA down regulation experiments and activity studies were used to examine changes in metabolite formation of one UGT isoform due to down regulation of a second UGT isoform. Selective siRNA directed towards UGT1A9 or UGT2B7 resulted in significant and selective decreases in their respective mRNA levels. As expected, the metabolism of the UGT1A9 substrate propofol decreased with UGT1A9 down regulation. Interestingly, UGT1A9 activity, but not UGT1A9 mRNA expression, was also diminished when UGT2B7 expression was selectively inhibited, implying potential interactions between the two isoforms. Minor changes to UGT1A4, UGT2B4 and UGT2B7 activity were also observed when UGT1A9 expression was selectively down regulated. To our knowledge, this represents the first piece of evidence that UGT protein–protein interactions occur in human hepatocytes and suggests that expression levels of UGT2B7 may directly impact the glucuronidation activity of selective UGT1A9 substrates. PMID:23562620

  1. Raloxifene glucuronidation in liver and intestinal microsomes of humans and monkeys: contribution of UGT1A1, UGT1A8 and UGT1A9.

    PubMed

    Kishi, Naoki; Takasuka, Akane; Kokawa, Yuki; Isobe, Takashi; Taguchi, Maho; Shigeyama, Masato; Murata, Mikio; Suno, Manabu; Hanioka, Nobumitsu

    2016-01-01

    1. Raloxifene is an antiestrogen that has been marketed for the treatment of osteoporosis, and is metabolized into 6- and 4'-glucuronides by UDP-glucuronosyltransferase (UGT) enzymes. In this study, the in vitro glucuronidation of raloxifene in humans and monkeys was examined using liver and intestinal microsomes and recombinant UGT enzymes (UGT1A1, UGT1A8 and UGT1A9). 2. Although the K(m) and CL(int) values for the 6-glucuronidation of liver and intestinal microsomes were similar between humans and monkeys, and species differences in Vmax values (liver microsomes, humans > monkeys; intestinal microsomes, humans < monkeys) were observed, no significant differences were noted in the K(m) or S50, Vmax and CL(int) or CLmax values for the 4'-glucuronidation of liver and intestinal microsomes between humans and monkeys. 3. The activities of 6-glucuronidation in recombinant UGT enzymes were UGT1A1 > UGT1A8 >UGT1A9 for humans, and UGT1A8 > UGT1A1 > UGT1A9 for monkeys. The activities of 4'-glucuronidation were UGT1A8 > UGT1A1 > UGT1A9 in humans and monkeys. 4. These results demonstrated that the profiles for the hepatic and intestinal glucuronidation of raloxifene by microsomes were moderately different between humans and monkeys.

  2. A new screening method to detect water-soluble antioxidants: acetaminophen (Tylenol) and other phenols react as antioxidants and destroy peroxynitrite-based luminol-dependent chemiluminescence.

    PubMed

    Van Dyke, K; Sacks, M; Qazi, N

    1998-01-01

    This study is based on a simple chemical interaction of peroxynitrite (O = N-O-O-) and luminol, which produces blue light upon oxidation. Since peroxynitrite has a half-life of about 1 s, a drug known as linsidomine (SIN-1) is used as a peroxynitrite generator. Peroxynitrite can oxidize lipids, proteins and nucleic acids. Upon the stimulation of inflammation and/or infection, macrophages and neutrophils can be induced to produce large amounts of peroxynitrite, which can oxidize phenols and sulphhydryl-containing compounds. Therefore, phenols and sulphhydryls eliminate peroxynitrite. This is an example of the Yin-Yang hypothesis e.g. oxidation-reduction. Acetaminophen (Tylenol) can inhibit fever and some types of pain without being a particularly effective anti-inflammatory. Since it is a phenol, it could act as a nitration target for peroxynitrite. Then peroxynitrite, the possible cause of pain and elevated temperature, might be destroyed in the reaction. Acetaminophen is a phenolic compound which produces a clear inhibitory dose-response curve with peroxynitrite in its range of clinical effectiveness. Whether acetaminophen actually works as we suggest is to be proven. Three different types of reaction could decrease the amount of peroxynitrite: (a) interference with base-catalysed opening of the SIN-1 molecule; (b) destruction of one or both substances needed to form it--superoxide and/or nitric oxide; when the SIN-1 degrades to superoxide and nitric oxide, the former may be destroyed by superoxide dismutase (SOD); (c) peroxynitrite may react directly with phenols (mono-, di-, tri- and tetraphenols), possibly by nitration. Nordihydroguaiaretic acid and 2-hydroxyestradiol (catechol estrogen) are potent inhibitors of luminol light emission. Epineprine, isoproterenol, pyrogallol, catechol and ascorbic acid (a classic antioxidant) are all inhibitors of luminol chemiluminescence. Isoproterenol, norepinephrine/and epinephrine first inhibit light but overall stimulate

  3. Determination of propofol glucuronide from hair sample by using mixed mode anion exchange cartridge and liquid chromatography tandem mass spectrometry.

    PubMed

    Kwak, Jae-Hwan; Kim, Hye Kyung; Choe, Sanggil; In, Sangwhan; Pyo, Jae Sung

    2016-03-15

    The main objective of this study was to develop and validate a simpler and less time consuming analytical method for determination of propofol glucuronide from hair sample, by using mixed mode anion exchange cartridge and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The study uses propofol glucuronide, a major metabolite of propofol, as a marker for propofol abuse. The hair sample was digested in sodium hydroxide solution and loaded in mixed-mode anion cartridge for solid phase extraction. Water and ethyl acetate were used as washing solvents to remove interfering substances from the hair sample. Consequently, 2% formic acid in ethyl acetate was employed to elute propofol glucuronide from the sorbent of mixed-mode anion cartridge, and analyzed by LC-MS/MS. The method validation parameters such as selectivity, specificity, LOD, LLOQ, accuracy, precision, recovery, and matrix effect were also tested. The linearity of calibration curves showed good correlation, with correlation coefficient 0.998. The LOD and LLOQ of the propofol glucuronide were 0.2 pg/mg and 0.5 pg/mg, respectively. The intra and inter-day precision and accuracy were acceptable within 15%. The mean values of recovery and matrix effect were in the range of 91.7-98.7% and 87.5-90.3%, respectively, signifying that the sample preparation, washing and extraction procedure were efficient, and there was low significant hair matrix effect for the extraction of propofol glucuronide from hair sample on the mixed mode anion cartridge. To evaluate the suitability of method, the hair of propofol administered rat was successfully analyzed with this method.

  4. β-Lactam analogues of combretastatin A-4 prevent metabolic inactivation by glucuronidation in chemoresistant HT-29 colon cancer cells.

    PubMed

    Malebari, Azizah M; Greene, Lisa M; Nathwani, Seema M; Fayne, Darren; O'Boyle, Niamh M; Wang, Shu; Twamley, Brendan; Zisterer, Daniela M; Meegan, Mary J

    2017-04-21

    Glucuronidation by uridine 5-diphosphoglucuronosyl transferase enzymes (UGTs) is a cause of intrinsic drug resistance in cancer cells. Glucuronidation of combretastatin A-4 (CA-4) was previously identified as a mechanism of resistance in hepatocellular cancer cells. Herein, we propose chemical manipulation of β-lactam bridged analogues of Combretastatin A-4 as a novel means of overcoming drug resistance associated with glucuronidation due to the expression of UGTs in the CA-4 resistant human colon cancer HT-29 cells. The alkene bridge of CA-4 is replaced with a β-lactam ring to circumvent potential isomerisation while the potential sites of glucuronate conjugation are deleted in the novel 3-substituted-1,4-diaryl-2-azetidinone analogues of CA-4. We hypothesise that glucuronidation of CA-4 is the mechanism of drug resistance in HT-29 cells. Ring B thioether containing 2-azetidinone analogues of CA-4 such as 4-(4-(methylthio)phenyl)-3-phenyl-1-(3,4,5-trimethoxyphenyl)azetidin-2-one (27) and 3-hydroxy-4-(4-(methylthio)phenyl)-1-(3,4,5-trimethoxyphenyl)azetidin-2-one (45) were identified as the most potent inhibitors of tumour cell growth, independent of UGT status, displaying antiproliferative activity in the low nanomolar range. These compounds also disrupted the microtubular structure in MCF-7 and HT-29 cells, and caused G2/M arrest and apoptosis. Taken together, these findings highlight the potential of chemical manipulation as a means of overcoming glucuronidation attributed drug resistance in CA-4 resistant human colon cancer HT-29 cells, allowing the development of therapeutically superior analogues.

  5. A novel method for the quantitation of gingerol glucuronides in human plasma or urine based on stable isotope dilution assays.

    PubMed

    Schoenknecht, Carola; Andersen, Gaby; Schieberle, Peter

    2016-11-15

    The bio-active compounds of ginger (Zingiber officinale Roscoe), the gingerols, are gaining considerable attention due to their numerous beneficial health effects. In order to elucidate the physiological relevance of the ascribed effects their bioavailability has to be determined taking their metabolization into account. To quantitate in vivo generated [6]-, [8]- and [10]-gingerol glucuronides in human plasma and urine after ginger tea consumption, a simultaneous and direct liquid chromatography-tandem mass spectrometry method based on stable isotope dilution assays was established and validated. The respective references as well as the isotopically labeled substances were synthesized and characterized by mass spectrometry and NMR. Selective isolation of gingerol glucuronides from human plasma and urine by a mixed-phase anion-exchange SPE method led to recovery rates between 80.8 and 98.2%. LC-MS/MS analyses in selected reaction monitoring modus enabled a highly sensitive quantitation of gingerol glucuronides with LoQs between 3.9-9.8nmol/L in plasma and 39.3-161.1nmol/L in urine. The method precision in plasma and urine varied in the range±15%, whereas the intra-day accuracy in plasma and urine showed values between 78 and 122%. The developed method was then applied to a pilot study in which two volunteers consumed one liter ginger tea. Pharmacokinetic parameters like the maximum concentration (cmax), the time to reach cmax (tmax), area under the curve (AUC), elimination rate constant (kel) and elimination half-life (t1/2) were calculated from the concentration-time curve of each gingerol glucuronide. The obtained results will enable more detailed investigation of gingerol glucuronides as bioactives in their physiologically relevant concentrations.

  6. Acetaminophen Induces Human Neuroblastoma Cell Death through NFKB Activation

    PubMed Central

    Posadas, Inmaculada; Santos, Pablo; Ceña, Valentín

    2012-01-01

    Neuroblastoma resistance to apoptosis may contribute to the aggressive behavior of this tumor. Therefore, it would be relevant to activate endogenous cellular death mechanisms as a way to improve neuroblastoma therapy. We used the neuroblastoma SH-SY5Y cell line as a model to study the mechanisms involved in acetaminophen (AAP)-mediated toxicity by measuring CYP2E1 enzymatic activity, NFkB p65 subunit activation and translocation to the nucleus, Bax accumulation into the mitochondria, cytochrome c release and caspase activation. AAP activates the intrinsic death pathway in the SH-SY5Y human neuroblastoma cell line. AAP metabolism is partially responsible for this activation, because blockade of the cytochrome CYP2E1 significantly reduced but did not totally prevent, AAP-induced SH-SY5Y cell death. AAP also induced NFkB p65 activation by phosphorylation and its translocation to the nucleus, where NFkB p65 increased IL-1β production. This increase contributed to neuroblastoma cell death through a mechanism involving Bax accumulation into the mitochondria, cytochrome c release and caspase3 activation. Blockade of NFkB translocation to the nucleus by the peptide SN50 prevented AAP-mediated cell death and IL-1β production. Moreover, overexpression of the antiapoptotic protein Bcl-xL did not decrease AAP-mediated IL-1β production, but prevented both AAP and IL-1β-mediated cell death. We also confirmed the AAP toxic actions on SK-N-MC neuroepithelioma and U87MG glioblastoma cell lines. The results presented here suggest that AAP activates the intrinsic death pathway in neuroblastoma cells through a mechanism involving NFkB and IL-1β. PMID:23166834

  7. Acute acetaminophen toxicity in transgenic mice with elevated hepatic glutathione.

    PubMed

    Rzucidlo, S J; Bounous, D I; Jones, D P; Brackett, B G

    2000-06-01

    Previous studies demonstrated that elevation of hepatic glutathione (GSH) concentrations protect against acetaminophen (APAP) hepatotoxicity in mice. Employing transgenic mice overexpressing glutathione synthetase, this study was conducted to determine if sustained elevation of hepatic GSH concentrations could ameliorate or prevent APAP toxicity. International Cancer Research transgenic mouse males and matched (ie same strain, sex, and age) control nontransgenic mice were pretreated ip with GSH synthetase substrate gamma-glutamylcysteinyl ethyl ester (gamma-GCE) or with saline. After a 16-h fast, mice received a single dose of 500 mg APAP/kg bw in saline ip and were sacrificed 4 h later. Other mice similarly pretreated were killed without APAP challenge. The elevated GSH concentrations in transgenic mice livers did not lessen APAP hepatotoxicity. Instead higher degrees of hepatotoxicity and nephrotoxicity were observed in transgenic mice than in controls as indicated by higher serum alanine aminotransferase activity and more severe histopathological lesions in transgenic mice livers and kidneys. Pretreatment with gamma-GCE did not affect either initial or post-APAP treatment tissue GSH concentrations or observed degrees of toxicity. Detection of a higher level of serum APAP in transgenic mice and the histopathological lesions found in transgenic mice kidneys together with no observable nephrotoxicity in control mice indicated early kidney damage in transgenic mice. Our findings suggest that high levels of GSH-APAP conjugates resulting from increased GSH concentrations in the livers of transgenic mice caused rapid kidney damage. Compromised excretory ability may have caused retention of APAP, which, in effect, elicited higher hepatotoxicity than that observed in nontransgenic mice.

  8. Mechanism of protection by metallothionein against acetaminophen hepatotoxicity

    SciTech Connect

    Saito, Chieko; Yan, H.-M.; Artigues, Antonio; Villar, Maria T.; Farhood, Anwar; Jaeschke, Hartmut

    2010-01-15

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced liver failure in the US. Metallothionein (MT) expression attenuates APAP-induced liver injury. However, the mechanism of this protection remains incompletely understood. To address this issue, C57BL/6 mice were treated with 100 mumol/kg ZnCl{sub 2} for 3 days to induce MT. Twenty-four hours after the last dose of zinc, the animals received 300 mg/kg APAP. Liver injury (plasma ALT activities, area of necrosis), DNA fragmentation, peroxynitrite formation (nitrotyrosine staining), MT expression, hepatic glutathione (GSH), and glutathione disulfide (GSSG) levels were determined after 6 h. APAP alone caused severe liver injury with oxidant stress (increased GSSG levels), peroxynitrite formation, and DNA fragmentation, all of which were attenuated by zinc-induced MT expression. In contrast, MT knockout mice were not protected by zinc. Hydrogen peroxide-induced cell injury in primary hepatocytes was dependent only on the intracellular GSH levels but not on MT expression. Thus, the protective effect of MT in vivo was not due to the direct scavenging of reactive oxygen species. Zinc treatment had no effect on the early GSH depletion kinetics after APAP administration, which is an indicator of the metabolic activation of APAP to its reactive metabolite N-acetyl-p-benzoquinone imine (NAPQI). However, MT was able to effectively trap NAPQI by covalent binding. We conclude that MT scavenges some of the excess NAPQI after GSH depletion and prevents covalent binding to cellular proteins, which is the trigger for the propagation of the cell injury mechanisms through mitochondrial dysfunction and nuclear DNA damage.

  9. Paracetamol (acetaminophen) efficacy and safety in the newborn.

    PubMed

    Cuzzolin, Laura; Antonucci, Roberto; Fanos, Vassilios

    2013-02-01

    Neonates can perceive pain, therefore an adequate analgesic therapy is a major issue not only from an ethical perspective but also to improve short- and long-term outcome. Fever during the neonatal period requires hospitalization and needs a treatment with an antipyretic agent because of the high risk of severe complications. Paracetamol (acetaminophen), the most commonly prescribed drug in paediatric patients for its analgesic and antipyretic effects, is the only agent recommended for use as an antipyretic in the newborn and has been recently proposed as a supplement therapy to opioids for postoperative analgesia. This article aims to give an updated overview on the use of paracetamol in newborns by presenting its pharmacological profile (mechanism of action, pharmacokinetics), recommendations for dosing regimens (oral or rectal administration: 25-30 mg/kg/day in preterm neonates of 30 weeks' gestation, 45 mg/kg/day in preterm neonates of 34 weeks' gestation, 60 mg/kg/day in term neonates; i.v. administration: indicatively 20-40 mg/kg/day depending on gestational age, with some differences among various guidelines) and clinical uses (more commonly as analgesic/antipyretic by oral or rectal route, but also i.v. in anaesthesia for postoperative analgesia and painful procedures in Neonatal Intensive Care Units). Moreover, drug tolerability is discussed in the light of its potential hepatotoxicity and the unique characteristics of the newborn patient. By analyzing the available literature and the dosing guidelines, a mismatch exists between the current clinical use of paracetamol and the recommendations, suggesting a cautious approach particularly in extremely preterm neonates.

  10. Pathophysiological role of the acute inflammatory response during acetaminophen hepatotoxicity

    SciTech Connect

    Cover, Cathleen; Liu Jie; Farhood, Anwar; Malle, Ernst; Waalkes, Michael P.; Bajt, Mary Lynn; Jaeschke, Hartmut . E-mail: jaeschke@email.arizona.edu

    2006-10-01

    Neutrophils are recruited into the liver after acetaminophen (AAP) overdose but the pathophysiological relevance of this acute inflammatory response remains unclear. To address this question, we compared the time course of liver injury, hepatic neutrophil accumulation and inflammatory gene mRNA expression for up to 24 h after treatment with 300 mg/kg AAP in C3Heb/FeJ and C57BL/6 mice. Although there was no relevant difference in liver injury (assessed by the increase of plasma alanine aminotransferase activities and the areas of necrosis), the number of neutrophils and the expression of several pro-inflammatory genes (e.g., tumor necrosis factor-{alpha}, interleukin-1{beta} and macrophage inflammatory protein-2) was higher in C3Heb/FeJ than in C57BL/6 mice. In contrast, the expression of the anti-inflammatory genes interleukin-10 and heme oxygenase-1 was higher in C57BL/6 mice. Despite substantial hepatic neutrophil accumulation, none of the liver sections from both strains stained positive for hypochlorite-modified proteins, a specific marker for a neutrophil-induced oxidant stress. In addition, treatment with the NADPH oxidase inhibitors diphenyleneiodonium chloride or apocynin or the anti-neutrophil antibody Gr-1 did not protect against AAP hepatotoxicity. Furthermore, although intercellular adhesion molecule-1 (ICAM-1) was previously shown to be important for neutrophil extravasation and tissue injury in several models, ICAM-1-deficient mice were not protected against AAP-mediated liver injury. Together, these data do not support the hypothesis that neutrophils aggravate liver injury induced by AAP overdose.

  11. Changes in Mouse Liver Protein Glutathionylation after Acetaminophen Exposure

    PubMed Central

    Yang, Xi; Greenhaw, James; Ali, Akhtar; Shi, Qiang; Roberts, Dean W.; Hinson, Jack A.; Muskhelishvili, Levan; Beger, Richard; Pence, Lisa M.; Ando, Yosuke; Sun, Jinchun; Davis, Kelly

    2012-01-01

    The role of protein glutathionylation in acetaminophen (APAP)-induced liver injury was investigated in this study. A single oral gavage dose of 150 or 300 mg/kg APAP in B6C3F1 mice produced increased serum alanine aminotransferase and aspartate aminotransferase levels and liver necrosis in a dose-dependent manner. The ratio of GSH to GSSG was decreased in a dose-dependent manner, suggesting that APAP produced a more oxidizing environment within the liver. Despite the increased oxidation state, the level of global protein glutathionylation was decreased at 1 h and continued to decline through 24 h. Immunohistochemical localization of glutathionylated proteins showed a complex dynamic change in the lobule zonation of glutathionylated proteins. At 1 h after APAP exposure, the level of glutathionylation decreased in the single layer of hepatocytes around the central veins but increased mildly in the remaining centrilobular hepatocytes. This increase correlated with the immunohistochemical localization of APAP covalently bound to protein. Thereafter, the level of glutathionylation decreased dramatically over time in the centrilobular regions with major decreases observed at 6 and 24 h. Despite the overall decreased glutathionylation, a layer of cells lying between the undamaged periportal region and the damaged centrilobular hepatocytes exhibited high levels of glutathionylation at 3 and 6 h in all samples and in some 24-h samples that had milder injury. These temporal and zonal pattern changes in protein glutathionylation after APAP exposure indicate that protein glutathionylation may play a role in protein homeostasis during APAP-induced hepatocellular injury. PMID:22045778

  12. Mouse Liver Protein Sulfhydryl Depletion after Acetaminophen Exposure

    PubMed Central

    Yang, Xi; Greenhaw, James; Shi, Qiang; Roberts, Dean W.; Hinson, Jack A.; Muskhelishvili, Levan; Davis, Kelly

    2013-01-01

    Acetaminophen (APAP)-induced liver injury is the leading cause of acute liver failure in many countries. This study determined the extent of liver protein sulfhydryl depletion not only in whole liver homogenate but also in the zonal pattern of sulfhydryl depletion within the liver lobule. A single oral gavage dose of 150 or 300 mg/kg APAP in B6C3F1 mice produced increased serum alanine aminotransferase levels, liver necrosis, and glutathione depletion in a dose-dependent manner. Free protein sulfhydryls were measured in liver protein homogenates by labeling with maleimide linked to a near infrared fluorescent dye followed by SDS-polyacrylamide gel electrophoresis. Global protein sulfhydryl levels were decreased significantly (48.4%) starting at 1 hour after the APAP dose and maintained at this reduced level through 24 hours. To visualize the specific hepatocytes that had reduced protein sulfhydryl levels, frozen liver sections were labeled with maleimide linked to horseradish peroxidase. The centrilobular areas exhibited dramatic decreases in free protein sulfhydryls while the periportal regions were essentially spared. These protein sulfhydryl-depleted regions correlated with areas exhibiting histopathologic injury and APAP binding to protein. The majority of protein sulfhydryl depletion was due to reversible oxidation since the global- and lobule-specific effects were essentially reversed when the samples were reduced with tris(2-carboxyethy)phosphine before maleimide labeling. These temporal and zonal pattern changes in protein sulfhydryl oxidation shed new light on the importance that changes in protein redox status might play in the pathogenesis of APAP hepatotoxicity. PMID:23093024

  13. Acetaminophen Induced Hepatotoxicity in Wistar Rats--A Proteomic Approach.

    PubMed

    Ilavenil, Soundharrajan; Al-Dhabi, Naif Abdullah; Srigopalram, Srisesharam; Ock Kim, Young; Agastian, Paul; Baru, Rajasekhar; Choi, Ki Choon; Valan Arasu, Mariadhas

    2016-01-28

    Understanding the mechanism of chemical toxicity, which is essential for cross-species and dose extrapolations, is a major challenge for toxicologists. Standard mechanistic studies in animals for examining the toxic and pathological changes associated with the chemical exposure have often been limited to the single end point or pathways. Toxicoproteomics represents a potential aid to the toxicologist to understand the multiple pathways involved in the mechanism of toxicity and also determine the biomarkers that are possible to predictive the toxicological response. We performed an acute toxicity study in Wistar rats with the prototype liver toxin; the acetaminophen (APAP) effects on protein profiles in the liver and its correlation with the plasma biochemical markers for liver injury were analyzed. Three separate groups--control, nontoxic (150 mg/kg) and toxic dose (1500 mg/kg) of APAP--were studied. The proteins extracted from the liver were separated by 2-DE and analyzed by MALDI-TOF. The differential proteins in the gels were analyzed by BIORAD's PDQuest software and identified by feeding the peptide mass fingerprint data to various public domain programs like Mascot and MS-Fit. The identified proteins in toxicity-induced rats were classified based on their putative protein functions, which are oxidative stress (31%), immunity (14%), neurological related (12%) and transporter proteins (2%), whereas in non-toxic dose-induced rats they were oxidative stress (9%), immunity (6%), neurological (14%) and transporter proteins (9%). It is evident that the percentages of oxidative stress and immunity-related proteins were up-regulated in toxicity-induced rats as compared with nontoxic and control rats. Some of the liver drug metabolizing and detoxifying enzymes were depleted under toxic conditions compared with non-toxic rats. Several other proteins were identified as a first step in developing an in-house rodent liver toxicoproteomics database.

  14. Melatonin prevents acetaminophen-induced nephrotoxicity in rats.

    PubMed

    Ilbey, Yusuf Ozlem; Ozbek, Emin; Cekmen, Mustafa; Somay, Adnan; Ozcan, Levent; Otünctemur, Alper; Simsek, Abdulmuttalip; Mete, Fatih

    2009-01-01

    Nephrotoxicity is a major complication of acetaminophen (APAP), a widely used analgesic and antipyretic drug, and there is no specific treatment for APAP-induced renal damage. It has been reported that reactive oxygen metabolites or free radicals are important mediators of APAP toxicity. In this study, the protective role of melatonin (MLT) on APAP-induced nephrotoxicity was investigated in rats. For this purpose, nephrotoxicity was induced in male Wistar albino rats by intraperitoneal (i.p.) administration of a single dose of 1,000 mg/kg APAP. Some of these rats also received i.p. melatonin (10 mg/kg) 20 min after administration of APAP. The rats were sacrificed 24 h after administration of APAP. Urea and creatinine levels were measured in the blood, and levels of malondialdehyde (MDA) and glutathione (GSH), and glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) activity were determined in renal tissue. Serum urea and creatinine levels increased significantly as a result of APAP nephrotoxicity. A significant increase in MDA and decreases in GSH level and GSH-Px, CAT, and SOD activity indicated that APAP-induced renal damage was mediated through oxidative stress. Significant beneficial changes were noted in serum and tissue oxidative stress indicators in rats treated with MLT. These biochemical observations were supplemented by histopathological examination of kidney sections, which revealed that MLT also reduced the severity of APAP-induced histological alterations in the kidney. These results indicate that administration of APAP causes oxidative stress to renal tissue and that MLT protects against the oxidative damage associated with APAP.

  15. The effect of acetaminophen on ubiquitin homeostasis in Saccharomyces cerevisiae

    PubMed Central

    Huseinovic, Angelina; van Leeuwen, Jolanda S.; van Welsem, Tibor; Stulemeijer, Iris; van Leeuwen, Fred; Vermeulen, Nico P. E.; Kooter, Jan M.; Vos, J. Chris

    2017-01-01

    Acetaminophen (APAP), although considered a safe drug, is one of the major causes of acute liver failure by overdose, and therapeutic chronic use can cause serious health problems. Although the reactive APAP metabolite N-acetyl-p-benzoquinoneimine (NAPQI) is clearly linked to liver toxicity, toxicity of APAP is also found without drug metabolism of APAP to NAPQI. To get more insight into mechanisms of APAP toxicity, a genome-wide screen in Saccharomyces cerevisiae for APAP-resistant deletion strains was performed. In this screen we identified genes related to the DNA damage response. Next, we investigated the link between genotype and APAP-induced toxicity or resistance by performing a more detailed screen with a library containing mutants of 1522 genes related to nuclear processes, like DNA repair and chromatin remodelling. We identified 233 strains that had an altered growth rate relative to wild type, of which 107 showed increased resistance to APAP and 126 showed increased sensitivity. Gene Ontology analysis identified ubiquitin homeostasis, regulation of transcription of RNA polymerase II genes, and the mitochondria-to-nucleus signalling pathway to be associated with APAP resistance, while histone exchange and modification, and vesicular transport were connected to APAP sensitivity. Indeed, we observed a link between ubiquitin levels and APAP resistance, whereby ubiquitin deficiency conferred resistance to APAP toxicity while ubiquitin overexpression resulted in sensitivity. The toxicity profile of various chemicals, APAP, and its positional isomer AMAP on a series of deletion strains with ubiquitin deficiency showed a unique resistance pattern for APAP. Furthermore, exposure to APAP increased the level of free ubiquitin and influenced the ubiquitination of proteins. Together, these results uncover a role for ubiquitin homeostasis in APAP-induced toxicity. PMID:28291796

  16. Synthesis of a precursor for the preparation of 9 alpha,11 alpha-tritiated 5 alpha-androstane-3 alpha,17 beta-diol 17-glucuronide

    SciTech Connect

    Rao, P.N.; Damodaran, K.M.

    1984-03-01

    Starting from 11 beta-hydroxytestosterone, the synthesis of a strategic precursor, C-9 (11) unsaturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide (9a), for the preparation of 9 alpha,11 alpha-tritiated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide has been achieved. The authors optimized the reaction conditions for catalytic reduction employing hydrogen and subsequent base hydrolysis followed by purification on Amberlite XAD-2 resin to obtain the saturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide.

  17. Puerarin-7-O-glucuronide, a water-soluble puerarin metabolite, prevents angiotensin II-induced cardiomyocyte hypertrophy by reducing oxidative stress.

    PubMed

    Hou, Ning; Cai, Bin; Ou, Cai-Wen; Zhang, Zhen-Hui; Liu, Xia-Wen; Yuan, Mu; Zhao, Gan-Jian; Liu, Shi-Ming; Xiong, Long-Gen; Luo, Jian-Dong; Luo, Cheng-Feng; Chen, Min-Sheng

    2017-02-16

    This study aimed to investigate the anti-oxidant and anti-hypertrophic effects of puerarin-7-O-glucuronide, a water-soluble puerarin metabolite. The anti-oxidant effects of puerarin-7-O-glucuronide were assessed by measurement of intracellular superoxide levels, total superoxide dismutase (SOD) activity, total anti-oxidant capacity, and glutathione (GSH)/glutathione disulfide (GSSG) ratio in cultured neonatal rat cardiomyocytes (NRCMs) stimulated with the xanthine oxidase (XO)/xanthine (X) system or angiotensin II. The activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and expression of NADPH oxidase subunits p22(phox) and p47(phox) were determined. The anti-hypertrophic effects of puerarin-7-O-glucuronide in angiotensin II-challenged NRCMs were characterized by changes in cell morphology and expression of hypertrophic genes. In the pharmacokinetic study, the plasma concentration of puerarin-7-O-glucuronide was determined by rapid resolution-liquid chromatography-tandem mass spectrometry (RR-LC-MS/MS). Puerarin-7-O-glucuronide prevented XO/X-induced increase in intracellular superoxide production and decreases in total SOD activity, GSH/GSSG ratio, and total anti-oxidant capacity. Puerarin-7-O-glucuronide also reversed angiotensin II-induced increases in intracellular superoxide production and NADPH oxidase activity and decreases in total SOD activity. These anti-oxidant effects of puerarin-7-O-glucuronide were accompanied by downregulation of p22(phox) and p47(phox). Furthermore, puerarin-7-O-glucuronide prevented angiotensin II-induced increases in cell surface area and perimeter, as well as changes in Nppa, Myh7, and Myh6. In the pharmacokinetic study, puerarin-7-O-glucuronide was cleared with a half-life of 0.94 h after intravenous administration. Puerarin could be detected in rat plasma, albeit in low concentration, as early as 5 min after intravenous administration of puerarin-7-O-glucuronide. These anti-oxidant and anti

  18. Identifying and applying a highly selective probe to simultaneously determine the O-glucuronidation activity of human UGT1A3 and UGT1A4

    PubMed Central

    Jiang, Li; Liang, Si-Cheng; Wang, Chao; Ge, Guang-Bo; Huo, Xiao-Kui; Qi, Xiao-Yi; Deng, Sa; Liu, Ke-Xin; Ma, Xiao-Chi

    2015-01-01

    Glucuronidation mediated by uridine 5′-diphospho (UDP)-glucuronosyltransferase is an important detoxification pathway. However, identifying a selective probe of UDP- glucuronosyltransferase is complicated because of the significant overlapping substrate specificity displayed by the enzyme. In this paper, desacetylcinobufagin (DACB) 3-O- and 16-O-glucuronidation were found to be isoform-specific probe reactions for UGT1A4 and UGT1A3, respectively. DACB was well characterized as a probe for simultaneously determining the catalytic activities of O-glucuronidation mediated by UGT1A3 and UGT1A4 from various enzyme sources, through a sensitive analysis method. PMID:25884245

  19. Skin of the male African catfish, Clarias gariepinus: a source of steroid glucuronides

    SciTech Connect

    Ali, S.A.; Schoonen, W.G.; Lambert, J.G.; Van den Hurk, R.; Van Oordt, P.G.

    1987-06-01

    Steroid metabolism in the skin of mature male African catfish, Clarias gariepinus, reared in the laboratory, was studied in vitro by tissue incubations with (/sup 3/H)pregnenolone, (/sup 3/H)dehydroepiandrosterone, (/sup 3/H)17 alpha-hydroxyprogesterone, (/sup 3/H)androstenedione, (/sup 14/C)11 beta-hydroxyandrostenedione, and (/sup 3/H)testosterone as precursors. While pregnenolone was not converted to any other steroid, dehydroepiandrosterone was transformed mainly to 5-androstene-3 beta, 17 beta-diol. The products of 17 alpha-hydroxyprogesterone incubations were 5 beta-pregnane-3 alpha,17 alpha-diol-20-one, 5 beta-pregnane-3 alpha,17 alpha, 20 beta-triol, and 5 beta-pregnan-17 alpha-o1-3,20-dione. The major steroids of androstenedione incubations were etiocholanolone, testosterone, and androsterone. Testosterone was converted mainly to etiocholanolone and androstenedione, and only small quantities of 11 beta-hydroxytestosterone, 11-ketotestosterone, and 11-ketoandrostenedione were the metabolites found in 11 beta-hydroxyandrostenedione incubation. These results demonstrated the presence of the enzymes 5 alpha- and 5 beta-reductases and 3 alpha-, 11 beta-, 17 beta-, and 20 beta-hydroxysteroid dehydrogenases in the skin. From enzymehistochemical results it appeared that the steroid conversions take place in the epithelial cells. Moreover, the presence of UDP-glucose dehydrogenase, an enzyme involved in the synthesis of glucuronic acid, in these cells indicates the possibility of steroid glucuronide formation. Indeed significant amounts of water-soluble steroid conjugates, particularly 5 beta-dihydrotestosterone- and testosterone-glucuronide, were found in the incubations with androstenedione and testosterone, indicating the presence of the UDP-glucuronosyl transferase in the catfish skin.

  20. Simultaneous modelling of the Michaelis-Menten kinetics of paracetamol sulphation and glucuronidation.

    PubMed

    Reith, David; Medlicott, Natalie J; Kumara De Silva, Rohana; Yang, Lin; Hickling, Jeremy; Zacharias, Mathew

    2009-01-01

    1. The aim of the present study was to perform an in vivo estimation of the Michaelis-Menten constants of the major metabolic pathways of paracetamol (APAP). 2. A two-occasion, single-dose cross-over trial was performed using 60 and 90 mg/kg doses of APAP in healthy patients undergoing third molar dental extraction. Plasma samples were collected over 24 h and urine was collected for 8 h after dosing. Twenty patients were enrolled in the study and complete data for plasma and urine were available for both doses for 13 volunteers who were included in the analysis; seven of the volunteers were men, the median age (range) was 22 years (19-31) and the median weight (range) was 68 kg (50-86). 3. The mean (95% CI) k(m) for APAP glucuronidation was 6.89 mmol/L (3.57-10.22) and the V(max) was 0.97 mmol/h per kg (0.65-1.28). The k(m) for APAP sulphation was 0.097 mmol/L (0.041-0.152) and the V(max) was 0.011 mmol/h per kg (0.009-0.013). For the combined excretion of APAP-cysteine and APAP-mercapturate, the k(m) was 0.303 mmol/L (0.131-0.475) and the V(max) was 0.004 mmol/h per kg (0.002-0.005). 4. The estimates for in vivo Michaelis-Menten constants for APAP glucuronidation and sulphation were in the order of those reported previously using in vitro methods.

  1. Acetaminophen increases the risk of arsenic-mediated development of hepatic damage in rats by enhancing redox-signaling mechanism.

    PubMed

    Majhi, Chhaya Rani; Khan, Saleem; Leo, Marie Dennis Marcus; Prawez, Shahid; Kumar, Amit; Sankar, Palanisamy; Telang, Avinash Gopal; Sarkar, Souvendra Nath

    2014-02-01

    We evaluated whether the commonly used analgesic-antipyretic drug acetaminophen can modify the arsenic-induced hepatic oxidative stress and also whether withdrawal of acetaminophen administration during the course of long-term arsenic exposure can increase susceptibility of liver to arsenic toxicity. Acetaminophen was co-administered orally to rats for 3 days following 28 days of arsenic pre-exposure (Phase-I) and thereafter, acetaminophen was withdrawn, but arsenic exposure was continued for another 28 days (Phase-II). Arsenic increased lipid peroxidation and reactive oxygen species (ROS) generation, depleted glutathione (GSH), and decreased superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione reductase (GR) activities. Acetaminophen caused exacerbation of arsenic-mediated lipid peroxidation and ROS generation and further enhancement of serum alanine aminotransferase and aspartate aminotransferase activities. In Phase-I, acetaminophen caused further GSH depletion and reduction in SOD, catalase, GPx and GR activities, but in Phase-II, only GPx and GR activities were more affected. Arsenic did not alter basal and inducible nitric oxide synthase (iNOS)-mediated NO production, but decreased constitutive NOS (cNOS)-mediated NO release. Arsenic reduced expression of endothelial NOS (eNOS) and iNOS genes. Acetaminophen up-regulated eNOS and iNOS expression and NO production in Phase-I, but reversed these effects in Phase-II. Results reveal that acetaminophen increased the risk of arsenic-mediated hepatic oxidative damage. Withdrawal of acetaminophen administration also increased susceptibility of liver to hepatotoxicity. Both ROS and NO appeared to mediate lipid peroxidation in Phase-I, whereas only ROS appeared responsible for peroxidative damage in Phase-II.

  2. Opposing effects of aspirin and acetaminophen use on risk of adult acute leukemia.

    PubMed

    Weiss, Joli R; Baker, Julie A; Baer, Maria R; Menezes, Ravi J; Nowell, Susan; Moysich, Kirsten B

    2006-02-01

    Regular use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been hypothesized to be associated with reduced risk of hematologic cancer, although previous results have been inconsistent. The current study investigated the effects of aspirin or acetaminophen use on adult acute leukemia risk among 169 individuals with leukemia and 676 age and sex matched hospital controls with non-neoplastic conditions who completed a comprehensive epidemiologic questionnaire. Results indicate that regular aspirin use may be associated with a modest decrease in leukemia risk [adjusted odds ratio (aOR), 0.84; 95% confidence interval (CI), 0.59-1.21]. In contrast, ever using acetaminophen was associated with elevated leukemia risk (aOR, 1.53; 95% CI, 1.03-2.26). Results did not differ between men and women. Other studies have demonstrated that acetaminophen is associated with transient decreases in DNA repair, and lymphocytes may be particularly susceptible to DNA damage, suggesting a mechanism for the elevated acute leukemia risk observed among acetaminophen users.

  3. An Experiment in Physical Chemistry: Polymorphism and Phase Stability in Acetaminophen (Paracetamol)

    ERIC Educational Resources Information Center

    Myrick, Michael L.; Baranowski, Megan; Profeta, Luisa T. M.

    2010-01-01

    Differential scanning calorimetry analyses of two easily prepared polymorphs of acetaminophen (also known as paracetamol) are recorded. The density of the forms can be found in the literature. Rules for heats of transition, heats of fusion, and density, as well as methods for determining the solid-solid transition temperature between the forms,…

  4. Effect of Tramadol/Acetaminophen on Motivation in Patients with Chronic Low Back Pain.

    PubMed

    Tetsunaga, Tomoko; Tetsunaga, Tomonori; Tanaka, Masato; Nishida, Keiichiro; Takei, Yoshitaka; Ozaki, Toshifumi

    2016-01-01

    Background. The contribution of apathy, frequently recognized in individuals with neurodegenerative diseases, to chronic low back pain (LBP) remains unclear. Objectives. To investigate levels of apathy and clinical outcomes in patients with chronic LBP treated with tramadol-acetaminophen. Methods. A retrospective case-control study involving 73 patients with chronic LBP (23 male, 50 female; mean age 71 years) treated with tramadol-acetaminophen (n = 36) and celecoxib (n = 37) was performed. All patients were assessed using the self-reported questionnaires. A mediation model was constructed using a bootstrapping method to evaluate the mediating effects of pain relief after treatment. Results. A total of 35 (55.6%) patients met the criteria for apathy. A four-week treatment regimen in the tramadol group conferred significant improvements in the Apathy scale and numerical rating scale but not in the Rolland-Morris Disability Questionnaire, Pain Disability Assessment Scale, or Pain Catastrophizing Scale. The depression component of the Hospital Anxiety and Depression Scale was lower in the tramadol group than in the celecoxib group. The mediation analysis found that the impact of tramadol-acetaminophen on the change in apathy was not mediated by the pain relief. Conclusions. Tramadol-acetaminophen was effective at reducing chronic LBP and conferred a prophylactic motivational effect in patients with chronic LBP.

  5. Lycopene pretreatment improves hepatotoxicity induced by acetaminophen in C57BL/6 mice.

    PubMed

    Bandeira, Ana Carla Balthar; da Silva, Rafaella Cecília; Rossoni, Joamyr Victor; Figueiredo, Vivian Paulino; Talvani, André; Cangussú, Silvia Dantas; Bezerra, Frank Silva; Costa, Daniela Caldeira

    2017-02-01

    Acetaminophen (APAP) is an antipyretic and analgesic drug that, in high doses, leads to severe liver injury and potentially death. Oxidative stress is an important event in APAP overdose. Researchers are looking for natural antioxidants with the potential to mitigate the harmful effects of reactive oxygen species in different models. Lycopene has been widely studied for its antioxidant properties. The aim of this study was to evaluate the antioxidant potential of lycopene pretreatment in APAP-induced liver injury in C57BL/6 mice. C57BL/6 male mice were divided into the following groups: control (C); sunflower oil (CO); acetaminophen 500mg/kg (APAP); acetaminophen 500mg/kg+lycopene 10mg/kg (APAP+L10), and acetaminophen 500mg/kg+lycopene 100mg/kg (APAP+L100). Mice were pretreated with lycopene for 14 consecutive days prior to APAP overdose. Analyses of blood serum and livers were performed. Lycopene was able to improve redox imbalance, decrease thiobarbituric acid reactive species level, and increase CAT and GSH levels. In addition, it decreased the IL-1β expression and the activity of MMP-2. This study revealed that preventive lycopene consumption in C57BL/6 mice can attenuate the effects of APAP-induced liver injury. Furthermore, by improving the redox state, and thus indicating its potential antioxidant effect, lycopene was also shown to have an influence on inflammatory events.

  6. A Biomedical Application of Activated Carbon Adsorption: An Experiment Using Acetaminophen and N-Acetylcysteine.

    ERIC Educational Resources Information Center

    Rybolt, Thomas R.; And Others

    1988-01-01

    Illustrates an interesting biomedical application of adsorption from solution and demonstrates some of the factors that influence the in vivo adsorption of drug molecules onto activated charcoal. Uses acetaminophen and N-acetylcysteine for the determination. Suggests several related experiments. (MVL)

  7. Cats Have Nine Lives, but Only One Liver: The Effects of Acetaminophen

    ERIC Educational Resources Information Center

    Dewprashad, Brahmadeo

    2009-01-01

    This case recounts the story of a student who gave her cat half of a Tylenol tablet not knowing its potential harmful effects. The cat survives, but the incident motivates the student to learn more about the reaction mechanism underlying the liver toxicity of acetaminophen. The case outlines three possible reaction schemes that would explain the…

  8. 76 FR 2691 - Prescription Drug Products Containing Acetaminophen; Actions To Reduce Liver Injury From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-14

    ... To Reduce Liver Injury From Unintentional Overdose AGENCY: Food and Drug Administration, HHS. ACTION... safety to help prevent liver damage due to acetaminophen overdosing, a serious public health problem...-containing prescription drug products to address new safety information about the risk of liver damage....

  9. Antioxidant and hepatoprotective potential of Pouteria campechiana on acetaminophen-induced hepatic toxicity in rats.

    PubMed

    Aseervatham, G Smilin Bell; Sivasudha, T; Sasikumar, J M; Christabel, P Hephzibah; Jeyadevi, R; Ananth, D Arul

    2014-03-01

    Pouteria campechiana (Kunth) Baehni. is used as a remedy for coronary trouble, liver disorders, epilepsy, skin disease, and ulcer. Therefore, the present study aims to investigate the antioxidant and hepatoprotective effect of polyphenolic-rich P. campechiana fruit extract against acetaminophen-intoxicated rats. Total phenolic and flavonoid contents of egg fruit were estimated followed by the determination of antioxidant activities. Treatment with P. campechiana fruit extract effectively scavenged the free radicals in a concentration-dependent manner within the range of the given concentrations in all antioxidant models. The presence of polyphenolic compounds were confirmed by high-performance thin-layer chromatography (HPTLC). The animals were treated with acetaminophen (250 mg/kg body weight; p.o.) thrice at the interval of every 5 days after the administration of P. campechiana aqueous extract and silymarin (50 mg/kg). Acetaminophen treatment was found to trigger an oxidative stress in liver, leading to an increase of serum marker enzymes. However, treatment with P. campechiana fruit extract significantly reduced the elevated liver marker enzymes (aspartate transaminase, alanine transaminase, and alkaline phosphatase) and increased the antioxidant enzymes (viz., superoxide dismutase and catalase) and glutathione indicating the effect of the extract in restoring the normal functional ability of hepatocytes. These results strongly suggest that P. campechiana fruit extract has strong antioxidant and significant hepatoprotective effect against acetaminophen-induced hepatotoxicity.

  10. c-Jun N-terminal kinase (JNK)-dependent acute liver injury from acetaminophen or tumor necrosis factor (TNF) requires mitochondrial Sab protein expression in mice.

    PubMed

    Win, Sanda; Than, Tin Aung; Han, Derick; Petrovic, Lydia M; Kaplowitz, Neil

    2011-10-07

    Sustained JNK activation plays a critical role in hepatotoxicity by acetaminophen or GalN/TNF-α. To address the importance of JNK translocation to mitochondria that accompanies sustained activation in these models, we assessed the importance of the expression of a potential initial target of JNK in the outer membrane of mitochondria, namely Sab (SH3 domain-binding protein that preferentially associates with Btk), also known as Sh3bp5 (SH3 domain-binding protein 5). Silencing the expression of Sab in the liver using adenoviral shRNA inhibited sustained JNK activation and mitochondrial targeting of JNK and the upstream MKK4 (MAPK kinase 4), accompanied by striking protection against liver injury in vivo and in cultured hepatocytes in both toxicity models. We conclude that mitochondrial Sab may serve as a platform for the MAPK pathway enzymes and that the interaction of stress-activated JNK with Sab is required for sustained JNK activation and toxicity.

  11. c-Jun N-terminal Kinase (JNK)-dependent Acute Liver Injury from Acetaminophen or Tumor Necrosis Factor (TNF) Requires Mitochondrial Sab Protein Expression in Mice*

    PubMed Central

    Win, Sanda; Than, Tin Aung; Han, Derick; Petrovic, Lydia M.; Kaplowitz, Neil

    2011-01-01

    Sustained JNK activation plays a critical role in hepatotoxicity by acetaminophen or GalN/TNF-α. To address the importance of JNK translocation to mitochondria that accompanies sustained activation in these models, we assessed the importance of the expression of a potential initial target of JNK in the outer membrane of mitochondria, namely Sab (SH3 domain-binding protein that preferentially associates with Btk), also known as Sh3bp5 (SH3 domain-binding protein 5). Silencing the expression of Sab in the liver using adenoviral shRNA inhibited sustained JNK activation and mitochondrial targeting of JNK and the upstream MKK4 (MAPK kinase 4), accompanied by striking protection against liver injury in vivo and in cultured hepatocytes in both toxicity models. We conclude that mitochondrial Sab may serve as a platform for the MAPK pathway enzymes and that the interaction of stress-activated JNK with Sab is required for sustained JNK activation and toxicity. PMID:21844199

  12. Effectiveness of postoperative intravenous acetaminophen (Acelio) after gastrectomy: A propensity score-matched analysis.

    PubMed

    Ohkura, Yu; Haruta, Shusuke; Shindoh, Junichi; Tanaka, Tsuyoshi; Ueno, Masaki; Udagawa, Harushi

    2016-11-01

    The aim of this study was to investigate the efficacy of postoperative scheduled intravenous acetaminophen to reduce the opioid use and enhance recovery after gastrectomy.Opioid use is reportedly associated with delayed recovery of gastrointestinal (GI) peristalsis and postoperative nausea/vomiting (PONV) despite of acceptable efficacy for pain control.Of 147 and 96 consecutive patients who underwent gastrectomy for gastric cancer before and after introduction of postoperative scheduled intravenous acetaminophen, propensity score matched population was created and short-term clinical outcomes were compared.Significant defervescence was demonstrated in Acetaminophen group (A-group) compared with control group (C-group) during the perioperative period (P < 0.001), whereas no significant difference was observed in postoperative inflammatory parameters. The incidence of postoperative complications was similar between the groups. The number of patient-controlled analgesia (PCA) pushes was significantly reduced in the A-group (P = 0.007) and the frequency of use of other nonopioid analgesics was also significantly reduced in the A-group (P < 0.001). Both daily and cumulative opioid use was significantly reduced in the A-group (P < 0.001). The time to first flatus and defecation was decreased in the A-group (P < 0.001 and P = 0.038, respectively). The incidence of PONV was significantly reduced from 26.0% to 12.5% after introduction of intravenous acetaminophen (P = 0.017), and hospital stay tended to be decreased in the A-group (13.2 vs 14.7 days, P = 0.069)Postoperative scheduled intravenous acetaminophen decreased opioid use and may be associated with enhanced recovery after gastrectomy.

  13. A safety assessment of fixed combinations of acetaminophen and acetylsalicylic acid, coformulated with caffeine.

    PubMed

    Bach, P H; Berndt, W O; Delzell, E; Dubach, U; Finn, W F; Fox, J M; Hess, R; Michielsen, P; Sandler, D P; Trump, B; Williams, G

    1998-11-01

    Overuse and abuse of phenacetin-containing mixed analgesics has contributed to end-stage renal disease. Combination analgesics, especially those coformulated with caffeine, have been implicated as imparting a greater risk of analgesic-associated nephropathy (AAN) than single or coformulated analgesics without caffeine. This has led to a recommendation that the sale of "two plus caffeine" analgesic mixtures be reclassified from over-the-counter to prescription only availability. There is a rational basis for coformulating acetylsalicylic acid (ASA) and acetaminophen (paracetamol) as this reduces the dose of each, without altering efficacy. The coformulation of caffeine with these analgesics has a significant adjuvant effect and increases analgesic efficacy 1.4-1.6-fold. Currently available animal and human data do not support the notion that the nephrotoxic risk from coformulated ASA and acetaminophen is higher than the risk from either ASA or acetaminophen alone, in equivalent analgesic doses. There are no epidemiological data that implicate caffeine in AAN, and only limited evidence that links excessive acetaminophen usage to renal disease. There is no evidence that caffeine increases analgesics papillotoxicity directly. The presence of caffeine in mixtures of analgesics are no more addictive than other sources of caffeine. There is no evidence to suggest that adding caffeine to analgesic mixtures enhances the potential for promoting analgesic misuse in the general population. Thus distinct therapeutic benefits of ASA, acetaminophen and caffeine appear to outweigh any known risk. It is doubtful if preventing the availability of these products will significantly affect the role of analgesic abuse/overuse in end-stage renal disease. Better risk management would come from a focused educational program, developed in a close collaboration between industry, healthcare professionals and consumer organizations, such a program must warn against the potential dangers of

  14. Glucuronidation of lipophilic substrates: preparation of 3-benzo[a]pyrenyl-beta-D-glucopyranosiduronic acid in multimilligram quantities by microsomal UDP-glucuronyl transferase.

    PubMed

    Johnson, D B; Swanson, M J; Barker, C W; Fanska, C B; Murrill, E E

    1979-01-01

    A convenient method for the enzymic conversion of multimilligram quantities of 3-hydroxybenzo[a]pyrene to 3-benzo[a]pyrenyl-beta-D-glucopyranosiduronic acid in 90% yield is described. Commercially available freeze-dried rabbit liver microsomes were incubated in the presence of UDPGA, 3-hydroxybenzo[a]pyrene, and Triton X-100 detergent (Figure 1). The course of the biosynthetic reaction was followed by fluorimetry. The glucuronide product was extracted from the acidified incubation supernate with ethyl acetate and the acid function of the glucuronide was utilized in an acid-base extraction procedure to purify the glucuronide from biological and unreacted starting material. The glucuronide precipitated from ethyl acetate and was collected by centrifugation. High pressure liquid chromatography and spectroscopic techniques were used to verify the structure and purity of 3-benzo[a]pyrenyl-beta-D-glucopyranosiduronic acid.

  15. Necrostatin-1 protects against reactive oxygen species (ROS)-induced hepatotoxicity in acetaminophen-induced acute liver failure

    PubMed Central

    Takemoto, Kenji; Hatano, Etsuro; Iwaisako, Keiko; Takeiri, Masatoshi; Noma, Naruto; Ohmae, Saori; Toriguchi, Kan; Tanabe, Kazutaka; Tanaka, Hirokazu; Seo, Satoru; Taura, Kojiro; Machida, Keigo; Takeda, Norihiko; Saji, Shigehira; Uemoto, Shinji; Asagiri, Masataka

    2014-01-01

    Excessive acetaminophen (APAP) use is one of the most common causes of acute liver failure. Various types of cell death in the damaged liver are linked to APAP-induced hepatotoxicity, and, of these, necrotic cell death of hepatocytes has been shown to be involved in disease pathogenesis. Until recently, necrosis was commonly considered to be a random and unregulated form of cell death; however, recent studies have identified a previously unknown form of programmed necrosis called receptor-interacting protein kinase (RIPK)-dependent necrosis (or necroptosis), which is controlled by the kinases RIPK1 and RIPK3. Although RIPK-dependent necrosis has been implicated in a variety of disease states, including atherosclerosis, myocardial organ damage, stroke, ischemia–reperfusion injury, pancreatitis, and inflammatory bowel disease. However its involvement in APAP-induced hepatocyte necrosis remains elusive. Here, we showed that RIPK1 phosphorylation, which is a hallmark of RIPK-dependent necrosis, was induced by APAP, and the expression pattern of RIPK1 and RIPK3 in the liver overlapped with that of CYP2E1, whose activity around the central vein area has been demonstrated to be critical for the development of APAP-induced hepatic injury. Moreover, a RIPK1 inhibitor ameliorated APAP-induced hepatotoxicity in an animal model, which was underscored by significant suppression of the release of hepatic enzymes and cytokine expression levels. RIPK1 inhibition decreased reactive oxygen species levels produced in APAP-injured hepatocytes, whereas CYP2E1 expression and the depletion rate of total glutathione were unaffected. Of note, RIPK1 inhibition also conferred resistance to oxidative stress in hepatocytes. These data collectively demonstrated a RIPK-dependent necrotic mechanism operates in the APAP-injured liver and inhibition of this pathway may be beneficial for APAP-induced fulminant hepatic failure. PMID:25349782

  16. Zinc Supplementation with Polaprezinc Protects Mouse Hepatocytes against Acetaminophen-Induced Toxicity via Induction of Heat Shock Protein 70

    PubMed Central

    Nishida, Tadashi; Ohata, Shuzo; Kusumoto, Chiaki; Mochida, Shinsuke; Nakada, Junya; Inagaki, Yoshimi; Ohta, Yoshiji; Matsura, Tatsuya

    2010-01-01

    Polaprezinc, a chelate compound consisting of zinc and l-carnosine, is clinically used as a medicine for gastric ulcers. It has been shown that induction of heat shock protein (HSP) is involved in protective effects of polaprezinc against gastric mucosal injury. In the present study, we investigated whether polaprezinc and its components could induce HSP70 and prevent acetaminophen (APAP) toxicity in mouse primary cultured hepatocytes. Hepatocytes were treated with polaprezinc, zinc sulfate or l-carnosine at the concentration of 100 µM for 9 h, and then exposed to 10 mM APAP. Polaprezinc or zinc sulfate increased cellular HSP70 expression. However, l-carnosine had no influence on it. Pretreatment of the cells with polaprezinc or zinc sulfate significantly suppressed cell death as well as cellular lipid peroxidation after APAP treatment. In contrast, pretreatment with polaprezinc did not affect decrease in intracellular glutathione after APAP. Furthermore, treatment with KNK437, an HSP inhibitor, attenuated increase in HSP70 expression induced by polaprezinc, and abolished protective effect of polaprezinc on cell death after APAP. These results suggested that polaprezinc, in particular its zinc component, induces HSP70 expression in mouse primary cultured hepatocytes, and inhibits lipid peroxidation after APAP treatment, resulting in protection against APAP toxicity. PMID:20104264

  17. Regulation of alternative macrophage activation in the liver following acetaminophen intoxication by stem cell-derived tyrosine kinase

    SciTech Connect

    Gardner, Carol R.; Hankey, Pamela; Mishin, Vladimir; Francis, Mary; Yu, Shan; Laskin, Jeffrey D.; Laskin, Debra L.

    2012-07-15

    Stem cell-derived tyrosine kinase (STK) is a transmembrane receptor reported to play a role in macrophage switching from a classically activated/proinflammatory phenotype to an alternatively activated/wound repair phenotype. In the present studies, STK{sup −/−} mice were used to assess the role of STK in acetaminophen-induced hepatotoxicity as evidence suggests that the pathogenic process involves both of these macrophage subpopulations. In wild type mice, centrilobular hepatic necrosis and increases in serum transaminase levels were observed within 6 h of acetaminophen administration (300 mg/kg, i.p.). Loss of STK resulted in a significant increase in sensitivity of mice to the hepatotoxic effects of acetaminophen and increased mortality, effects independent of its metabolism. This was associated with reduced levels of hepatic glutathione, rapid upregulation of inducible nitric oxide synthase, and prolonged induction of heme oxygenase-1, suggesting excessive oxidative stress in STK{sup −/−} mice. F4/80, a marker of mature macrophages, was highly expressed on subpopulations of Kupffer cells in livers of wild type, but not STK{sup −/−} mice. Whereas F4/80{sup +} macrophages rapidly declined in the livers of wild type mice following acetaminophen intoxication, they increased in STK{sup −/−} mice. In wild type mice hepatic expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-12, products of classically activated macrophages, increased after acetaminophen administration. Monocyte chemotactic protein-1 (MCP-1) and its receptor, CCR2, as well as IL-10, mediators involved in recruiting and activating anti-inflammatory/wound repair macrophages, also increased in wild type mice after acetaminophen. Loss of STK blunted the effects of acetaminophen on expression of TNFα, IL-1β, IL-12, MCP-1 and CCR2, while expression of IL-10 increased. Hepatic expression of CX3CL1, and its receptor, CX3CR1 also increased in STK{sup −/−} mice

  18. Identification of Flavone Glucuronide Isomers by Metal Complexation and Tandem Mass Spectrometry: Regioselectivity of UDP-Glucuronosyltransferase Isozymes in the Biotransformation of Flavones

    PubMed Central

    Robotham, Scott A.; Brodbelt, Jennifer S.

    2013-01-01

    Flavone Glucuronide isomers of five flavones (chrysin, apigenin, luteolin, baicalein, and scutellarein) were differentiated by collision induced dissociation (CID) of [Co(II) (flavone-H) (4,7-diphenyl-1,10-phenanthroline)2]+ complexes. The complexes were generated via post-column addition of a metal/ligand solution after separation of the glucuronide products generated upon incubation of each flavone with an array of UDP-glucuronosyl-transferase (UGT) isozymes. Elucidation of the glucuronide isomers allowed a systematic investigation of the regioselectivity of twelve human UDP-glucuronosyl-transferase (UGT) isozymes, including eight UGT1A and four UGT2B isozymes. Glucuronidation of the 7-OH position was the preferred site for all the flavones except for luteolin, which possessed adjacent hydroxyl groups on the B ring. For all flavones and UGT isozymes, glucuronidation of the 5-OH position was never observed. As confirmed by the metal complexation/MS/MS strategy, glucuronidation of the 6-OH position only occurred for baicalein and scutellarein when incubated with three of the UGT isozymes. PMID:23362992

  19. Simultaneous determination of mycophenolic acid and its glucuronide and glycoside derivatives in canine and feline plasma by UHPLC-UV.

    PubMed

    Rivera, Sol Maiam; Hwang, Julianne K; Slovak, Jeniffer E; Court, Michael H; Villarino, Nicolas F

    2017-02-01

    Cats and dogs can suffer from multiple autoimmune diseases. Mycophenolic acid (MPA) is a potentially useful immunosuppressant drug in cats and dogs, because of its well-documented efficacy in controlling autoimmune disease in humans. However, the pharmacokinetics and pharmacodynamics in these species remain to be determined. We have developed and validated a sensitive, precise, accurate and reproducible method that provides consistent quantification of MPA and its major derivatives, MPA phenol glucoside and MPA phenol glucuronide, in canine and feline plasma using ultra-high-pressure liquid chromatography coupled to an ultraviolet detector. The main advantages of this novel method include a small sample volume, easy sample preparation, a short chromatographic analysis time and the option to select either phenolphthalein β-d-glucuronide or mycophenolic acid carboxybutoxy ether as internal standard. Results of validation indicate that this analytical method is suitable to study the plasma disposition of MPA and its derivatives in dogs and cats.

  20. Identification of brain-targeted bioactive dietary quercetin-3-O-glucuronide as a novel intervention for Alzheimer's disease.

    PubMed

    Ho, Lap; Ferruzzi, Mario G; Janle, Elsa M; Wang, Jun; Gong, Bing; Chen, Tzu-Ying; Lobo, Jessica; Cooper, Bruce; Wu, Qing Li; Talcott, Stephen T; Percival, Susan S; Simon, James E; Pasinetti, Giulio Maria

    2013-02-01

    Epidemiological and preclinical studies indicate that polyphenol intake from moderate consumption of red wines may lower the relative risk for developing Alzheimer's disease (AD) dementia. There is limited information regarding the specific biological activities and cellular and molecular mechanisms by which wine polyphenolic components might modulate AD. We assessed accumulations of polyphenols in the rat brain following oral dosage with a Cabernet Sauvignon red wine and tested brain-targeted polyphenols for potential beneficial AD disease-modifying activities. We identified accumulations of select polyphenolic metabolites in the brain. We demonstrated that, in comparison to vehicle-control treatment, one of the brain-targeted polyphenol metabolites, quercetin-3-O-glucuronide, significantly reduced the generation of β-amyloid (Aβ) peptides by primary neuron cultures generated from the Tg2576 AD mouse model. Another brain-targeted metabolite, malvidin-3-O-glucoside, had no detectable effect on Aβ generation. Moreover, in an in vitro analysis using the photo-induced cross-linking of unmodified proteins (PICUP) technique, we found that quercetin-3-O-glucuronide is also capable of interfering with the initial protein-protein interaction of Aβ(1-40) and Aβ(1-42) that is necessary for the formation of neurotoxic oligomeric Aβ species. Lastly, we found that quercetin-3-O-glucuronide treatment, compared to vehicle-control treatment, significantly improved AD-type deficits in hippocampal formation basal synaptic transmission and long-term potentiation, possibly through mechanisms involving the activation of the c-Jun N-terminal kinases and the mitogen-activated protein kinase signaling pathways. Brain-targeted quercetin-3-O-glucuronide may simultaneously modulate multiple independent AD disease-modifying mechanisms and, as such, may contribute to the benefits of dietary supplementation with red wines as an effective intervention for AD.

  1. Ethyl glucuronide in hair and fingernails as a long-term alcohol biomarker

    PubMed Central

    Berger, Lisa; Fendrich, Michael; Jones, Joseph; Fuhrmann, Daniel; Plate, Charles; Lewis, Douglas

    2014-01-01

    Aims This study aimed to evaluate the performance of ethyl glucuronide (EtG) in hair and fingernails as a long-term alcohol biomarker. Design Cross-sectional survey with probability sampling. Setting Midwestern United States. Participants Participants were 606 undergraduate college students between the ages of 18 and 25 years at the time of selection for potential study participation. Measurements EtG concentrations in hair and fingernails were measured by liquid chromatography-tandem mass spectrometry at three thresholds [30 picograms (pg) per milligram (mg); 20 pg/mg; and 8 pg/mg]. Any weekly alcohol use, increasing-risk drinking and high-risk drinking on average during the past 12 weeks was assessed by participant interview using the time-line follow-back method. Findings In both hair and fingernails at all three EtG thresholds, sensitivity was greatest for the high-risk drinking group [hair: 0.43, confidence interval (CI) = 0.17, 0.69 at 30 pg/mg, 0.71, CI = 0.47, 0.95 at 20 pg/mg; 0.93, CI = 0.79, 1.00 at 8 pg/mg; fingernails: 1.00, CI = 1.00–1.00 at 30, 20 and 8 pg/mg] and specificity was greatest for any alcohol use (hair: 1.00, CI = 1.00, 1.00 at 30 and 20 pg/mg; 0.97, CI = 0.92–0.99 at 8 pg/mg; fingernails: 1.00, CI = 1.00–1.00 at 30, 20 and 8 pg/mg). Areas under the receiver operating characteristic curves were significantly higher for EtG concentration in fingernails than hair for any weekly alcohol use (P = 0.02, DeLong test, two-tailed) and increasing-risk drinking (P = 0.02, DeLong test, two-tailed). Conclusions Ethyl glucuronide, especially in fingernails, may have potential as a quantitative indicator of alcohol use. PMID:24524319

  2. Examination of sex differences in fatty acid ethyl ester and ethyl glucuronide hair analysis.

    PubMed

    Gareri, Joey; Rao, Chitra; Koren, Gideon

    2014-06-01

    Clinical studies examining performance of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in identifying excessive alcohol consumption have been primarily conducted in male populations. An impact of hair cosmetics in producing both false-negative EtG results and false-positive FAEE results has been demonstrated, suggesting a possible bias in female populations. This study evaluates FAEE-positive hair samples (>0.50 ng/mg) from n = 199 female and n = 73 male subjects for EtG. Higher FAEE/EtG concordance was observed amongst male over female subjects. Performance of multiple proposed EtG cut-off levels were assessed; amongst female samples, FAEE/EtG concordance was 36.2% (30 pg/mg), 36.7% (27 pg/mg), and 43.7% (20 pg/mg). Non-coloured hair demonstrated a two-fold increase in concordance (41.8 v. 20.8%) over coloured hair in the female cohort. FAEE levels did not differ between male and female subjects; however they were lower in coloured samples (p = 0.046). EtG was lower in female subjects (p = 0.019) and coloured samples (p = 0.026). A total of n = 111 female samples were discordant. Amongst discordant samples (EtG-negative), 26% had evidence of recent alcohol use including consultation histories (n = 20) and detectable cocaethylene (n = 9); 29% of discordant samples were coloured. False-negative risk with ethyl glucuronide analysis in females was mediated by cosmetic colouring. These findings suggest that combined analysis of FAEE and EtG is optimal when assessing a female population and an EtG cut-off of 20 pg/mg is warranted when using combined analysis. While concordant FAEE/EtG-positive findings constitute clear evidence, discordant FAEE/EtG findings should still be considered suggestive evidence of chronic excessive alcohol consumption.

  3. Improvement of Physico-mechanical Properties of Partially Amorphous Acetaminophen Developed from Hydroalcoholic Solution Using Spray Drying Technique

    PubMed Central

    Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi

    2013-01-01

    Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968

  4. Use of acetaminophen (paracetamol) during pregnancy and the risk of attention-deficit/hyperactivity disorder in the offspring.

    PubMed

    Andrade, Chittaranjan

    2016-03-01

    Prenatal exposure to acetaminophen may result in compromised neurodevelopment through inflammatory and immunologic mechanisms, through predisposition to oxidative stress, and through endocrine, endogenous cannabinoid, and other mechanisms. Several small and large prospective studies have found an association between gestational acetaminophen exposure and attention-deficit/hyperactivity disorder (ADHD)-like behaviors, use of ADHD medication, and ADHD diagnoses in offspring during childhood; the only negative study was a small investigation that examined only one aspect of attention as an outcome. Creditably, most of the studies adjusted analyses for many (but not all) confounds associated with ADHD risk. Importantly, one pivotal study also adjusted for pain, infection, inflammation, and fever to reduce confounding by indication; this study found a dose-dependent risk. In the light of the finding of a single study that infection and fever during pregnancy by themselves do not raise the ADHD risk, it appears possible that the use of acetaminophen during pregnancy is itself responsible for the increased risk of ADHD. This suggests that acetaminophen may not be as safe in pregnancy as is widely believed. However, since fever during pregnancy may itself be associated with adverse gestational outcomes, given the present level of uncertainty about the ADHD risk with acetaminophen, it is suggested that, until more data are available, the use of acetaminophen in pregnancy should not be denied in situations in which the need for the drug is clear.

  5. Hepatoprotective activity of Tribulus terrestris extract against acetaminophen-induced toxicity in a freshwater fish (Oreochromis mossambicus).

    PubMed

    Kavitha, P; Ramesh, R; Bupesh, G; Stalin, A; Subramanian, P

    2011-12-01

    The potential protective role of Tribulus terrestris in acetaminophen-induced hepatotoxicity in Oreochromis mossambicus was investigated. The effect of oral exposure of acetaminophen (500 mg/kg) in O. mossambicus at 24-h duration was evaluated. The plant extract (250 mg/kg) showed a remarkable hepatoprotective activity against acetaminophen-induced hepatotoxicity. It was judged from the tissue-damaging level and antioxidant levels in liver, gill, muscle and kidney tissues. Further acetaminophen impact induced a significant rise in the tissue-damaging level, and the antioxidant level was discernible from the enzyme activity modulations such as glutamate oxaloacetic transaminase, glutamate pyruvic transaminase, alkaline phosphatase, acid phosphatase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, lipid peroxidase and reduced glutathione. The levels of all these enzymes have significantly (p < 0.05) increased in acetaminophen-treated fish tissues. The elevated levels of these enzymes were significantly controlled by the treatment of T. terrestris extract (250 kg/mg). Histopathological changes of liver, gill and muscle samples were compared with respective controls. The results of the present study specify the hepatoprotective and antioxidant properties of T. terrestris against acetaminophen-induced toxicity in freshwater fish, O. mossambicus.

  6. Plasma and liver acetaminophen-protein adduct levels in mice after acetaminophen treatment: Dose–response, mechanisms, and clinical implications

    SciTech Connect

    McGill, Mitchell R.; Lebofsky, Margitta; Norris, Hye-Ryun K.; Slawson, Matthew H.; Bajt, Mary Lynn; Xie, Yuchao; Williams, C. David; Wilkins, Diana G.; Rollins, Douglas E.; Jaeschke, Hartmut

    2013-06-15

    At therapeutic doses, acetaminophen (APAP) is a safe and effective analgesic. However, overdose of APAP is the principal cause of acute liver failure in the West. Binding of the reactive metabolite of APAP (NAPQI) to proteins is thought to be the initiating event in the mechanism of hepatotoxicity. Early work suggested that APAP-protein binding could not occur without glutathione (GSH) depletion, and likely only at toxic doses. Moreover, it was found that protein-derived APAP-cysteine could only be detected in serum after the onset of liver injury. On this basis, it was recently proposed that serum APAP-cysteine could be used as diagnostic marker of APAP overdose. However, comprehensive dose–response and time course studies have not yet been done. Furthermore, the effects of co-morbidities on this parameter have not been investigated. We treated groups of mice with APAP at multiple doses and measured liver GSH and both liver and plasma APAP-protein adducts at various timepoints. Our results show that protein binding can occur without much loss of GSH. Importantly, the data confirm earlier work that showed that protein-derived APAP-cysteine can appear in plasma without liver injury. Experiments performed in vitro suggest that this may involve multiple mechanisms, including secretion of adducted proteins and diffusion of NAPQI directly into plasma. Induction of liver necrosis through ischemia–reperfusion significantly increased the plasma concentration of protein-derived APAP-cysteine after a subtoxic dose of APAP. While our data generally support the measurement of serum APAP-protein adducts in the clinic, caution is suggested in the interpretation of this parameter. - Highlights: • Extensive GSH depletion is not required for APAP-protein binding in the liver. • APAP-protein adducts appear in plasma at subtoxic doses. • Proteins are adducted in the cell and secreted out. • Coincidental liver injury increases plasma APAP-protein adducts at subtoxic doses

  7. An immunoassay for the detection of triclosan-O-glucuronide, a primary human urinary metabolite of triclosan.

    PubMed

    Ranganathan, Anupama; Gee, Shirley J; Hammock, Bruce D

    2015-09-01

    Triclosan-O-glucuronide (TCSG) is one of the primary urinary metabolites of the antibacterial compound triclosan or TCS that is found in many personal care products and consumer goods. We have developed a competitive, indirect heterologous ELISA for the detection of the target TCSG in urine. Such an ELISA for TCSG could be developed as a useful tool to measure this important biomarker of human exposure to TCS. Immunogens were prepared by conjugating TCSG to thyroglobulin, via heterobifunctional cross-linkers AEDP or 3-[(2-aminoethyl)dithio] propionic acid•hydrochloride and TFCS or N-[ε-trifluoroacetylcaproyloxy]succinimide ester. The coating antigen was prepared by the direct conjugation of TCSG to bovine serum albumin. Antibodies raised in rabbits 2619, 2621 (immunogen TCSG-AEDP-Thy), and 2623 (immunogen TCSG-TFCS-Thy), and the coating antigen were screened and characterized to determine their optimal concentrations. The optimized ELISA, developed with antibody 2621, gave an IC50 value of 2.85 ng/mL, with the linear range (IC20-IC80) determined to be 2.6-24.8 ng/mL. Selectivity of the assay was assessed by measuring cross-reactivity of antibody 2621 to related congeners such as the aglycone TCS, triclosan-O-sulfate, triclocarban, a polybrominated diphenyl ether derivative, and 3-phenoxybenzyl alcohol glucuronide. There was virtually no recognition by antibody 2621 to any of these cross-reactants. Graphical Abstract Urinary biomarker analysis of triclosan glucuronide.

  8. β-Glucuronidase activity and mitochondrial dysfunction: the sites where flavonoid glucuronides act as anti-inflammatory agents.

    PubMed

    Kawai, Yoshichika

    2014-05-01

    Epidemiological and experimental studies suggest that the consumption of flavonoid-rich diets decreases the risk of various chronic diseases such as cardiovascular diseases. Although studies on the bioavailability of flavonoids have been well-characterized, the tissue and cellular localizations underlying their biological mechanisms are largely unknown. The development and application of novel monoclonal antibodies revealed that macrophages could be the major target of dietary flavonoids in vivo. Using macrophage-like cell lines in vitro, we examined the molecular basis of the interaction between the macrophages and flavonoids, especially the glucuronide metabolites. We have found that extracellular β-glucuronidase secreted from macrophages is essential for the bioactivation of the glucuronide conjugates into the aglycone, and that the enzymatic activity, which requires an acidic pH, is promoted by the increased secretion of lactate in response to the mitochondrial dysfunction. This review describes our recent findings indicating the molecular mechanisms responsible for the anti-inflammatory activity of dietary flavonoids within the inflammation sites. We propose that the extracellular activity of β-glucuronidase associated with the status of the mitochondrial function in the target cells might be important biomarkers for the specific sites where the glucuronides of dietary flavonoids can act as anti-atherosclerotic and anti-inflammatory agents in vivo.

  9. Quantitative Determination of Common Urinary Odorants and Their Glucuronide Conjugates in Human Urine

    PubMed Central

    Wagenstaller, Maria; Buettner, Andrea

    2013-01-01

    Our previous study on the identification of common odorants and their conjugates in human urine demonstrated that this substance fraction is a little-understood but nonetheless a promising medium for analysis and diagnostics in this easily accessible physiological medium. Smell as an indicator for diseases, or volatile excretion in the course of dietary processes bares high potential for a series of physiological insights. Still, little is known today about the quantitative composition of odorous or volatile targets, as well as their non-volatile conjugates, both with regard to their common occurrence in urine of healthy subjects, as well as in that of individuals suffering from diseases or other physiological misbalancing. Accordingly, the aim of our study was to develop a highly sensitive and selective approach to determine the common quantitative composition of selected odorant markers in healthy human subjects, as well as their corresponding glucuronide conjugates. We used one- and two-dimensional high resolution gas chromatography-mass spectrometry in combination with stable isotope dilution assays to quantify commonly occurring and potent odorants in human urine. The studies were carried out on both native urine and on urine that had been treated by glucuronidase assays, with analysis of the liberated odor-active compounds using the same techniques. Analytical data are discussed with regard to their potential translation as future diagnostic tool. PMID:24958143

  10. Temporal indication of cannabis use by means of THC glucuronide determination.

    PubMed

    Mareck, Ute; Haenelt, Nadine; Geyer, Hans; Guddat, Sven; Kamber, Matthias; Brenneisen, Rudolf; Thevis, Mario; Schänzer, Wilhelm

    2009-11-01

    According to the regulations of the World Anti-Doping Agency (WADA), the use of cannabinoids is forbidden in competition. In doping controls, the detection of cannabinoid misuse is based on the analysis of the non-psychoactive metabolite 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (carboxy-THC). The determination of values greater than 15 ng/mL in urine represents an adverse analytical finding; however, no accurate prediction of the time of application is possible as the half-life of carboxy-THC ranges between three and four days. Consequently the detection of carboxy-THC in doping control urine samples collected in competition might also result from cannabis use in out-of-competition periods. The analysis of the glucuronide of the pharmacologically active delta 9-tetrahydrocannabinol (THC-gluc) may represent a complementary indicator for the detection of cannabis misuse in competition.An assay for the determination of THC-gluc in human urine was established. The sample preparation consisted of liquid-liquid extraction of urine specimens, and extracts were analysed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Authentic doping-control urine samples as well as specimens obtained from a controlled smoking study were analysed and assay characteristics such as specificity, detection limit (0.1 ng/mL), precision (>90%), recovery ( approximately 80%), and extraction efficiency (90%) were determined.

  11. Stability of ethyl glucuronide in urine, post-mortem tissue and blood samples.

    PubMed

    Schloegl, Haiko; Dresen, Sebastian; Spaczynski, Karin; Stoertzel, Mylène; Wurst, Friedrich Martin; Weinmann, Wolfgang

    2006-03-01

    The stability of ethyl glucuronide (EtG) under conditions of degradation was examined in urine samples of nine volunteers and in post-mortem tissue (liver, skeletal muscle) and blood taken from seven corpses at autopsies. Analysis was performed via LC-MS/MS. EtG concentrations in urine samples ranged from 2.5 to 296.5 mg/l. When stored at 4 degrees C in airtight test tubes, EtG concentrations remained relatively constant; when stored at room temperature (RT) for 5 weeks in ventilated vials, variations of EtG concentrations ranged from a 30% decrease to an 80% increase, with an average of 37.5% increase. Liver and skeletal muscle tissue of three corpses with positive blood alcohol concentrations (BAC; ranging from 0.106 to 0.183 g%) were stored for 4 weeks and analysed periodically. EtG concentrations decreased 27.7% on average in 4 weeks storage at RT but EtG was still detectable in all samples with initial EtG concentrations higher than 1 mug/g. Blood and liver samples of four corpses with negative BACs were stored at RT after addition of 0.1 g% ethanol, and no new formation of EtG was observed.

  12. Determination of ethyl glucuronide in human hair by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    PubMed

    Yaldiz, Fadile; Daglioglu, Nebile; Hilal, Ahmet; Keten, Alper; Gülmen, Mete Korkut

    2013-10-01

    Ethyl glucuronide (EtG) is a direct metabolite of ethanol and has been utilized as a marker for alcohol intake. This study presents development, validation and application of a new hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for the analysis of EtG in human hair samples. The linearity was assessed in the range of 5-2000 pg/mg hair, with a correlation coefficient of >0.99. The method was selective and sensitive, with a limit of detection (LOD) and limit of quantitation (LOQ) of 0.05 pg/mg and 0.18 pg/mg in hair, respectively. Differently from the extraction procedures in the literature, a fast and simple liquid-liquid method was used and highest recoveries and cleanest extracts were obtained. The method was successfully applied to 30 human hair samples which were taken from those who state they consume alcohol. EtG concentrations in the hair samples of alcohol users participated in this study, ranged between 1.34 and 82.73 pg/mg. From the concentration of EtG in hair strands 20 of the 30 subjects can be considered regular moderate drinkers.

  13. Morphine-3-D glucuronide stability in postmortem specimens exposed to bacterial enzymatic hydrolysis.

    PubMed

    Carroll, F T; Marraccini, J V; Lewis, S; Wright, W

    2000-12-01

    Medical examiners frequently rely on the finding of free morphine present in postmortem specimens to assist in certifying deaths associated with narcotics. In vitro hydrolysis of morphine-3-D glucuronide (M3DG) to free morphine was studied using variable specimen pH, initial degree of specimen putrefaction, storage temperature and time, and the effectiveness of sodium fluoride (NaF) preservation. Reagent M3DG was added to opiate-free fresh blood and urine and to autopsy-derived blood specimens. Reagent bovine glucuronidase was also added to certain specimens. Freshly collected and refrigerated NaF-preserved blood produced minimal free morphine, whereas four of five autopsy blood specimens produced free morphine from M3DG. Increased storage time, temperature, and initial degree of putrefaction resulted in greater free morphine generation despite the absence of viable bacteria. Hydrolysis occurring during specimen storage can generate free morphine from M3DG and may result in erroneous conclusions in certifying narcotic deaths.

  14. Quercetin-3-O-glucuronide induces ABCA1 expression by LXRα activation in murine macrophages

    SciTech Connect

    Ohara, Kazuaki; Wakabayashi, Hideyuki; Taniguchi, Yoshimasa; Shindo, Kazutoshi; Yajima, Hiroaki; Yoshida, Aruto

    2013-11-29

    Highlights: •The major circulating quercetin metabolite (Q3GA) activated LXRα. •Q3GA induced ABCA1 via LXRα activation in macrophages. •Nelumbo nucifera leaf extracts contained quercetin glycosides. •N. nucifera leaf extract feeding elevated HDLC in mice. -- Abstract: Reverse cholesterol transport (RCT) removes excess cholesterol from macrophages to prevent atherosclerosis. ATP-binding cassette, subfamily A, member 1 (ABCA1) is a crucial cholesterol transporter involved in RCT to produce high density lipoprotein-cholesterol (HDLC), and is transcriptionally regulated by liver X receptor alpha (LXRα), a nuclear receptor. Quercetin is a widely distributed flavonoid in edible plants which prevented atherosclerosis in an animal model. We found that quercetin-3-O-glucuronide (Q3GA), a major quercetin metabolite after absorption from the digestive tract, enhanced ABCA1 expression, in vitro, via LXRα in macrophages. In addition, leaf extracts of a traditional Asian edible plant, Nelumbo nucifera (NNE), which contained abundant amounts of quercetin glycosides, significantly elevated plasma HDLC in mice. We are the first to present experimental evidence that Q3GA induced ABCA1 in macrophages, and to provide an alternative explanation to previous studies on arteriosclerosis prevention by quercetin.

  15. Nasal administration of morphine-6-glucuronide in sheep--a pharmacokinetic study.

    PubMed

    Illum, L; Davis, S S; Pawula, M; Fisher, A N; Barrett, D A; Farraj, N F; Shaw, P N

    1996-11-01

    The pharmacokinetics of morphine-6-glucuronide (M6G) after both intravenous dosing and nasal administration were studied in sheep. The nasal formulation consisted of M6G in combination with an absorption promoting delivery system in the form of chitosan. The mean half-life of M6G after intravenous administration was 51.0 +/- 8.2 min and that after intranasal dosing was 45.0 +/- 5.5 min. M6G clearance and volume of distribution were 5.4 +/- 1.5 mL min-1 kg-1 and 0.4 +/- 0.1 L kg-1 respectively. The plasma profile after nasal administration demonstrated rapid absorption of M6G. The bioavailability of M6G in the chitosan formulation was found to be 31.4%. These results suggest that M6G administered in combination with the chitosan delivery system may be considered as a suitable non-parenteral means of administering this analgesic.

  16. Stability of ethyl glucuronide in hair reference materials after accelerated aging.

    PubMed

    Ammann, D; Becker, R; Nehls, I

    2015-12-01

    Two different hair reference materials, one produced from authentic hair displaying an ethyl glucuronide (EtG) content of about 25 pg/mg and one obtained by fortification of blank hair to an EtG level of 85 pg/mg were submitted to accelerated aging between 4 °C and 60 °C for periods between one and 24 months. Subsequently, the EtG content was determined in the aged samples and untreated reference samples stored at -22 °C under repeatability conditions following the so-called isochronous approach. The EtG content remained stable even at 40 °C for 24 months and at 60 °C over six months. This is in contrast to many organic analytes contained in trace concentrations in diverse matrices. A slight but significant increase of the recovered EtG in case of authentic hair samples having been exposed for 24 months between 4 °C and 60 °C may be due to a temperature-driven process that allows increased recoveries of the physiologically embedded EtG.

  17. Determination of ethyl glucuronide and fatty acid ethyl esters in hair samples.

    PubMed

    Oppolzer, David; Barroso, Mário; Passarinha, Luís; Gallardo, Eugenia

    2017-04-01

    Hair testing for alcohol biomarkers is an important tool for monitoring alcohol consumption. We propose two methods for assessing alcohol exposure through combined analysis of ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) species (ethyl myristate, palmitate, stearate and oleate) in hair (30 mg). EtG was analysed by liquid chromatography-tandem mass spectrometry, while FAEEs were analysed by gas chromatography-tandem mass spectrometry using electron impact ionization. Both methods were validated according to internationally accepted guidelines. Linearity was proven between 3 and 500 pg/mg for EtG and 30-5000 pg/mg for FAEEs, and the limits of quantification were 3 pg/mg for EtG and 30 pg/mg for each of the four FAEEs. Precision and accuracy were considered adequate, processed EtG samples were found to be stable for up to 96 h left in the injector and processed FAEEs samples for up to 24 h. Matrix effects were not significant. Both methods were applied to the analysis of 15 authentic samples, using the cut-off values proposed by the Society of Hair Testing for interpretation. The results agreed well with the self-reported alcohol consumption in most cases, and demonstrated the suitability of the methods to be applied in routine analysis of alcohol biomarkers, allowing monitoring consumption using low sample amounts.

  18. Determination of ethyl glucuronide in hair to assess excessive alcohol consumption in a student population.

    PubMed

    Oppolzer, David; Barroso, Mário; Gallardo, Eugenia

    2016-03-01

    Hair analysis for ethyl glucuronide (EtG) was used to evaluate the pattern of alcohol consumption amongst the Portuguese university student population. A total of 975 samples were analysed. For data interpretation, the 2014 guidelines from the Society of Hair Testing (SoHT) for the use of alcohol markers in hair for the assessment of both abstinence and chronic excessive alcohol consumption were considered. EtG concentrations were significantly higher in the male population. The effect of hair products and cosmetics was evaluated by analysis of variance (ANOVA), and significant lower concentrations were obtained when conditioner or hair mask was used or when hair was dyed. Based on the analytical data and information obtained in the questionnaires from the participants, receiver operating characteristic (ROC) curves were constructed in order to determine the ideal cut-offs for our study population. Optimal cut-off values were estimated at 7.3 pg/mg for abstinence or rare occasional drinking control and 29.8 pg/mg for excessive consumption. These values are very close to the values suggested by the SoHT, proving their adequacy to the studied population. Overall, the obtained EtG concentrations demonstrate that participants are usually well aware of their consumption pattern, correlating with the self-reported consumed alcohol quantity, consumption habits and excessive consumption close to the time of hair sampling.

  19. UHPLC-MS/MS quantification of buprenorphine, norbuprenorphine, methadone, and glucuronide conjugates in umbilical cord plasma.

    PubMed

    Kyle, Amy Redmond; Carmical, Jennifer; Shah, Darshan; Pryor, Jason; Brown, Stacy

    2015-10-01

    Opioid use during pregnancy can result in the newborn being physically dependent on the substance, thus experiencing drug withdrawal, termed neonatal abstinence syndrome (NAS). Buprenorphine and methadone are two drugs used to treat opioid withdrawal and are approved for use in pregnancy. Quantification of these compounds in umbilical cord plasma would help assess in utero exposure of neonates in cases of buprenorphine or methadone use during pregnancy. An LC-MS/MS method using solid-phase extraction sample preparation was developed and validated for the simultaneous quantification of methadone, buprenorphine, norbuprenorphine, and glucuronide metabolites in umbilical cord plasma. The average accuracy (percentage error) and precision (relative standard deviation) were <15% for each validated concentration. Our data establishes a 2 week maximum freezer storage window in order to