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https://www.readbyqxmd.com/read/28088388/activation-of-gr-but-not-pxr-by-dexamethasone-attenuated-acetaminophen-hepatotoxicities-via-fgf21-induction
#1
Saurabh G Vispute, Pengli Bu, Yuan Le, Xingguo Cheng
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...
January 11, 2017: Toxicology
https://www.readbyqxmd.com/read/28077325/role-of-14-3-3-sigma-in-over-expression-of-p-gp-by-rifampin-and-paclitaxel-stimulation-through-interaction-with-pxr
#2
So Won Kim, Md Hasanuzzaman, Munju Cho, Nam Hyun Kim, Hye-Young Choi, Jung Woo Han, Hyun June Park, Ji Won Oh, Jae-Gook Shin
In this study, we presented the role of 14-3-3σ to activate CK2-Hsp90β-PXR-MDR1 pathway on rifampin and paclitaxel treated LS174T cells and in vivo LS174T cell-xenografted nude mouse model. Following several in vitro and in vivo experiments, rifampin and paclitaxel were found to be stimulated the CK2-Hsp90β-PXR-MDR1 pathway. Of the proteins in this pathway, Pregnane X receptor (PXR) is a representative transcription factor of multidrug resistance protein 1 (MDR1). We constructed FLAG-PXR-LS174T stable cell lines and discovered 22 proteins that interacted with PXR on rifampin treatment...
January 7, 2017: Cellular Signalling
https://www.readbyqxmd.com/read/28064419/pharmacokinetics-and-pharmacogenetics-of-carbamazepine-in-children
#3
Natasa Djordjevic, Slobodan M Jankovic, Jasmina R Milovanovic
Although carbamazepine is one of the oldest anticonvulsant drugs, it is still heavily utilized for treatment of epilepsy in children. The aim of this article was to review the current knowledge about pharmacokinetics and pharmacogenetics of carbamazepine in children. The literature for this review was systematically searched for in the MEDLINE and SCINDEKS databases. Oral bioavailability of carbamazepine in children is about 75-85%, and it is approximately 75-85% bound to plasma proteins. Apparent volume of distribution is 1...
January 7, 2017: European Journal of Drug Metabolism and Pharmacokinetics
https://www.readbyqxmd.com/read/28058446/hepatotoxic-effects-of-cyproconazole-and-prochloraz-in-wild-type-and-hcar-hpxr-mice
#4
Philip Marx-Stoelting, Katrin Ganzenberg, Constanze Knebel, Flavia Schmidt, Svenja Rieke, Helen Hammer, Felix Schmidt, Oliver Pötz, Michael Schwarz, Albert Braeuning
The agricultural fungicides cyproconazole and prochloraz exhibit hepatotoxicity in rodent studies and are tumorigenic following chronic exposure. Both substances are suspected to act via a CAR (constitutive androstane receptor)/PXR (pregnane-X-receptor)-dependent mechanism. Human relevance of these findings is under debate. A 28-day toxicity study was conducted in mice with humanized CAR and PXR (hCAR/hPXR) with two dose levels (50 or 500 ppm) of both substances, using the model CAR activator phenobarbital as a reference...
January 6, 2017: Archives of Toxicology
https://www.readbyqxmd.com/read/28043194/differential-regulation-of-intestinal-efflux-transporters-by-pregnancy-in-mice
#5
Jamie E Moscovitz, Gabriel Yarmush, Guadalupe Herrera-Garcia, Grace L Guo, Lauren M Aleksunes
1. In the intestines, the nuclear receptors farnesoid X receptor (Fxr) and pregnane X receptor (Pxr) regulate the transcription of metabolizing enzymes and transporters that dictate the absorption of nutrients and xenobiotics. 2. Here, we sought to determine whether Fxr and Pxr signaling pathways are disrupted in response to high-circulating concentrations of steroid hormones late in pregnancy leading to altered transporter expression. To test this, ileum were collected from virgin and pregnant C57BL/6 mice on gestation days 14, 17 and 19...
January 3, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/28027470/performance-of-a-novel-atrazine-induced-cerebellar-toxicity-in-quail-coturnix-c-coturnix-activating-pxr-car-pathway-responses-and-disrupting-cytochrome-p450-homeostasis
#6
Jun Xia, Lei Qin, Zheng-Hai Du, Jia Lin, Xue-Nan Li, Jin-Long Li
Atrazine is well known to be a biologically hazardous substance with toxic effects, but atrazine-induced neurotoxicity remains unclear. The aim of this study was to investigate the mechanisms of atrazine-induced cerebellar toxicity. To determine atrazine-exerted potential neurotoxicity, quails were treated with 50, 250 and 500 mg/kg atrazine by gavage administration for 45 days. Notably, the changes of cytochrome P450 enzyme system (CYP450s) were observed in atrazine-exposed quails. The contents of cytochrome P450 (CYP450) and Cytochrome b5 (Cyt b5) and the activities of NADPH-cytochrome c reductase (NCR), aminopyrin N-demethylase (APND) and aniline-4-hydeoxylase (AH) were increased and erythromycin N-demethylase (ERND) was decreased in quail cerebellum...
December 18, 2016: Chemosphere
https://www.readbyqxmd.com/read/28025333/modulation-of-bilirubin-neurotoxicity-by-the-abcb1-transporter-in-the-ugt1-lethal-mouse-model-of-neonatal-hyperbilirubinemia
#7
Luka Bočkor, Giulia Bortolussi, Simone Vodret, Alessandra Iaconcig, Jana Jašprová, Jaroslav Zelenka, Libor Vitek, Claudio Tiribelli, Andrés F Muro
Moderate neonatal jaundice is the most common clinical condition during newborn life. However, a combination of factors may result in acute hyperbilirubinemia, placing infants at risk of developing bilirubin encephalopathy and death by kernicterus. While most risk factors are known, the mechanisms acting to reduce susceptibility to bilirubin neurotoxicity remain unclear. The presence of modifier genes modulating the risk of developing bilirubin-induced brain damage is increasingly being recognised. The Abcb1 and Abcc1 members of the ABC family of transporters have been suggested to have an active role in exporting unconjugated bilirubin from the central nervous system into plasma...
December 25, 2016: Human Molecular Genetics
https://www.readbyqxmd.com/read/28006928/sufentanil-and-midazolam-dosing-and-pharmacogenetic-factors-in-pediatric-analgosedation-and-withdrawal-syndrome
#8
K Hronová, P Pokorná, L Posch, O Slanař
Our aim was to describe the effect of dosing and genetic factors on sufentanil- and midazolam-induced analgosedation and withdrawal syndrome (WS) in pediatric population. Analgosedation and withdrawal syndrome development were monitored using COMFORT-neo/-B scores and SOS score. Length of therapy, dosing of sufentanil and midazolam were recorded. Genotypes of selected candidate polymorphisms in CYP3A5, COMT, ABCB1, OPRM1 and PXR were analysed. In the group of 30 neonates and 18 children, longer treatment duration with midazolam of 141 h (2 - 625) vs...
December 21, 2016: Physiological Research
https://www.readbyqxmd.com/read/28006925/bile-acids-nuclear-receptors-and-cytochrome-p450
#9
J Juřica, G Dovrtělová, K Nosková, O Zendulka
This review summarizes the importance of bile acids (BA) as important regulators of various homeostatic mechanisms with detailed focus on cytochrome P450 (CYP) enzymes. In the first part, synthesis, metabolism and circulation of BA is summarized and BA are reviewed as physiological ligands of nuclear receptors which regulate transcription of genes involved in their metabolism, transport and excretion. Notably, PXR, FXR and VDR are the most important nuclear receptors through which BA regulate transcription of CYP genes involved in the metabolism of both BA and xenobiotics...
December 21, 2016: Physiological Research
https://www.readbyqxmd.com/read/27988401/geniposide-attenuates-anit-induced-cholestasis-through-regulation-of-transporters-and-enzymes-involved-in-bile-acids-homeostasis-in-rats
#10
Lingling Wang, Guixin Wu, Feihua Wu, Nan Jiang, Yining Lin
ETHNOPHARMACOLOGICAL RELEVANCE: Geniposide (GE) is one of the major iridoid glycosides isolated from the fruit of Gardenia jasminoides Ellis that has been used to treat hepatic disorders including cholestasis. However, the underlying mechanisms for GE ameliorating the reduction in bile acids accumulation by α-naphthylisothiocyanate (ANIT) remain unclear. AIM OF THE STUDY: The purpose of this study is to characterize the efficacy of GE in regulation of bile acids uptake, synthesis, metabolism, and transport in ANIT-induced rats...
January 20, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/27932985/pregnane-x-receptor-pxr-mediated-gene-repression-and-cross-talk-of-pxr-with-other-nuclear-receptors-via-coactivator-interactions
#11
REVIEW
Petr Pavek
Pregnane X receptor is a ligand-activated nuclear receptor (NR) that mainly controls inducible expression of xenobiotics handling genes including biotransformation enzymes and drug transporters. Nowadays it is clear that PXR is also involved in regulation of intermediate metabolism through trans-activation and trans-repression of genes controlling glucose, lipid, cholesterol, bile acid, and bilirubin homeostasis. In these processes PXR cross-talks with other NRs. Accumulating evidence suggests that the cross-talk is often mediated by competing for common coactivators or by disruption of coactivation and activity of other transcription factors by the ligand-activated PXR...
2016: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/27926596/donor-genotype-and-intragraft-expression-of-cyp3a5-reflect-the-response-to-steroid-treatment-during-acute-renal-allograft-rejection
#12
N V Rekers, T M Flaig, M J K Mallat, M J Spruyt-Gerritse, M Zandbergen, J D H Anholts, I M Bajema, M C Clahsen-van Groningen, J Yang, J W de Fijter, F H J Claas, S Brakemeier, N Lachmann, R Kreutz, E de Heer, K Budde, J Bolbrinker, M Eikmans
BACKGROUND: Glucocorticoid-refractory acute rejection is a risk factor for inferior renal allograft outcome. We investigated genetic predisposition to the response to steroid treatment of acute allograft rejection. METHODS: Single nucleotide polymorphisms of genes involved in glucocorticoid signaling (GR, GLCCI1) and drug metabolism and transport (CYP3A5, ABCB1, and PXR) were analyzed in kidney transplant recipients (1995-2005, Leiden cohort, n=153) treated with methylprednisolone...
December 6, 2016: Transplantation
https://www.readbyqxmd.com/read/27918128/mulberroside-a-suppresses-pxr-mediated-transactivation-and-gene-expression-of-p-gp-in-ls174t-cells
#13
Yuhua Li, Ling Huang, Jiahong Sun, Xiaohua Wei, Jinhua Wen, Guoping Zhong, Min Huang, Huichang Bi
Mulberroside A (Mul A) is the main bioactive constituents of Sangbaipi, which is officially listed in the Chinese Pharmacopoeia. The pregnane X receptor (PXR) has been recognized as the critical mediator of human P-glycoprotein (P-gp) gene transactivation. In this study, the effect of Mul A on PXR-mediated transactivation and gene expression of P-gp was investigated. It was found that Mul A significantly suppressed PXR-mediated P-gp luciferase activity induced by rifampicin (Rif). Furthermore, Rif induced an elevation of P-gp expression and transport activity, which was apparently suppressed by Mul A...
December 5, 2016: Journal of Biochemical and Molecular Toxicology
https://www.readbyqxmd.com/read/27899892/age-dependent-hepatic-udp-glucuronosyltransferase-gene-expression-and-activity-in-children
#14
Elizabeth Neumann, Huma Mehboob, Jacqueline Ramírez, Snezana Mirkov, Min Zhang, Wanqing Liu
UDP-glucuronosyltransferases (UGTs) are important phase II drug metabolism enzymes. The aim of this study was to explore the relationship between age and changes in mRNA expression and activity of major human hepatic UGTs, as well as to understand the potential regulatory mechanism underlying this relationship. Using previously generated data, we investigated age-dependent mRNA expression levels of 11 hepatic UGTs (UGT1A1, UGT1A3, UGT1A4, UGT1A5, UGT1A6, UGT1A9, UGT2B4, UGT2B7, UGT2B10, UGT2B15, and UGT2B17) and 16 transcription factors (AHR, AR, CAR, ESR2, FXR, GCCR, HNF1a, HNF3a, HNF3b, HNF4a, PPARA, PPARG, PPARGC, PXR, SP1, and STAT3) in liver tissue of donors (n = 38) ranging from 0 to 25 years of age...
2016: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/27878971/pregnane-x-receptors-regulate-cyp2c8-and-p-glycoprotein-to-impact-on-the-resistance-of-nsclc-cells-to-taxol
#15
Yan Chen, Wandan Huang, Feiyu Chen, Guoping Hu, Fenglei Li, Jianhua Li, Aiguo Xuan
Cytochrome P450 2C8 (CYP2C8) is one of the enzymes that primarily participate in producing metabolisms of medications and P-glycoprotein (P-gp) has been regarded as one of the important molecules in chemotherapeutically induced multidrug resistance (MDR). In addition, the pregnane X receptor (PXR) is involved in regulating both CYP2C8 and P-gp. We aim to research the effect of PXR on Taxol-resistant non-small-cell lung cancer (NSCLC cells) via regulating CYP2C8 and P-gp. NSCLC cells were treated with SR12813, LY335979, or PXR siRNA...
December 2016: Cancer Medicine
https://www.readbyqxmd.com/read/27876007/effect-of-pregnane-x-receptor-1b-genetic-polymorphisms-on-postoperative-analgesia-with-fentanyl-in-chinese-patients-undergoing-gynecological-surgery
#16
Jing-Jing Yuan, Xiao-Jing Ma, Zhi-Song Li, Yan-Zi Chang, Wei Zhang, Quan-Cheng Kan, Jun-Kai Hou, Li-Rong Zhang
BACKGROUND: The purpose of the study was to investigate the effects of the pregnane X receptor (PXR)*1B polymorphisms on CYP3A4 enzyme activity and postoperative fentanyl consumption in Chinese patients undergoing gynecological surgery. METHODS: A total of 287 females of Han ethnicity, aged 20 to 50 years old, ASA I or II, scheduled to abdominal total hysterectomy or myomectomy under general anesthesia were enrolled. The analgesic model used was fentanyl consumption via patient-controlled intravenous analgesia (PCIA) in the post-operative period...
November 23, 2016: BMC Medical Genetics
https://www.readbyqxmd.com/read/27871908/acetylated-deoxycholic-dca-and-cholic-ca-acids-are-potent-ligands-of-pregnane-x-pxr-receptor
#17
Alejandro Carazo, Lucie Hyrsova, Jan Dusek, Hana Chodounska, Alzbeta Horvatova, Karel Berka, Vaclav Bazgier, Hongying Gan-Schreier, Waleé Chamulitrat, Eva Kudova, Petr Pavek
The Pregnane X (PXR), Vitamin D (VDR) and Farnesoid X (FXR) nuclear receptors have been shown to be receptors of bile acids controlling their detoxification or synthesis. Chenodeoxycholic (CDCA) and lithocholic (LCA) acids are ligands of FXR and VDR, respectively, whereas 3-keto and acetylated derivates of LCA have been described as ligands for all three receptors. In this study, we hypothesized that oxidation or acetylation at position 3, 7 and 12 of bile acids DCA (deoxycholic acid), LCA, CA (cholic acid), and CDCA by detoxification enzymes or microbiome may have an effect on the interactions with bile acid nuclear receptors...
January 4, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/27871799/molecular-mechanisms-of-pfoa-induced-toxicity-in-animals-and-humans-implications-for-health-risks
#18
REVIEW
Kan Li, Peng Gao, Ping Xiang, Xuxiang Zhang, Xinyi Cui, Lena Q Ma
As an emerging persistent organic pollutant (POP), perfluorooctanoate (PFOA) is one of the most abundant perfluorinated compounds (PFCs) in the environment. This review summarized the molecular mechanisms and signaling pathways of PFOA-induced toxicity in animals and humans as well as their implications for health risks in humans. Traditional PFOA-induced signal pathways such as peroxisome proliferating receptor alpha (PPARα), constitutive androstane receptor (CAR), farnesoid X receptor (FXR), and pregnane-X receptor (PXR) may not be important for PFOA-induced health effects on humans...
November 18, 2016: Environment International
https://www.readbyqxmd.com/read/27856527/role-of-glucocorticoid-receptor-and-pregnane-x-receptor-in-dexamethasone-induction-of-rat-hepatic-aryl-hydrocarbon-receptor-nuclear-translocator-and-nadph-cytochrome-p450-oxidoreductase
#19
Sarah R Hunter, Alex Vonk, Anne K Mullen Grey, David S Riddick
The aryl hydrocarbon receptor (AHR) nuclear translocator (ARNT), as the AHR's heterodimerization partner, and NADPH-cytochrome P450 oxidoreductase (POR), as the key electron donor for all microsomal P450s, are independent and indispensable components in the adaptive and toxic responses to polycyclic aromatic hydrocarbons. Expression of both ARNT and POR in rat liver is induced by dexamethasone (DEX), a synthetic glucocorticoid known to activate both the glucocorticoid receptor (GR) and the pregnane X receptor (PXR)...
November 16, 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/27852458/treatment-of-estrogen-dependent-diseases-design-synthesis-and-profiling-of-a-selective-17%C3%AE-hsd1-inhibitor-with-sub-nanomolar-ic50-for-a-proof-of-principle-study
#20
Ahmed S Abdelsamie, Chris J van Koppen, Emmanuel Bey, Mohamed Salah, Carsten Börger, Lorenz Siebenbürger, Matthias W Laschke, Michael D Menger, Martin Frotscher
Current endocrine therapeutics for the estrogen-dependent disease endometriosis often lead to considerable side-effects as they act by reducing estrogen action systemically. A more recent approach takes advantage of the fact that the weak estrogen estrone (E1) which is abundant in the plasma, is activated in the target cell to the highly estrogenic estradiol (E2) by 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1). 17β-HSD1 is overexpressed in endometriosis and thus a promising target for the treatment of this disease, with the prospect of less target-associated side-effects...
November 4, 2016: European Journal of Medicinal Chemistry
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