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https://www.readbyqxmd.com/read/29775950/drechmerin-h-a-novel-1-2-2-18-diseco-indole-diterpenoid-from-the-fungus-drechmeria-sp-as-a-natural-agonist-of-human-pregnane-x-receptor
#1
Jian-Chao Zhao, Zhi-Lin Luan, Jia-Hao Liang, Zhong-Bin Cheng, Cheng-Peng Sun, Ya-Li Wang, Meng-Yue Zhang, Tian-Yuan Zhang, Yong Wang, Tian-Mei Yang, Ying-Ying Wu, Yi-Xuan Zhang, Xin-Yu Zhao, Xiao-Chi Ma
A novel 1(2), 2(18)-diseco indole diterpenoid, drechmerin H (1), was isolated from the fermentation broth of Drechmeria sp. together with a new indole diterpenoid, 2'-epi terpendole A (3), and a known analogue, terpendole A (2). Their structures were determined by HRESIMS, 1D and 2D NMR, ECD, and X-ray single crystal diffraction analyses as well as quantum chemical calculation. The abosulte configuration of terpendole A (2) was determined for the first time. Compound 1 displayed the significant agonistic effect on pregnane X receptor (PXR) with EC50 value of 134...
May 9, 2018: Bioorganic Chemistry
https://www.readbyqxmd.com/read/29760129/pharmacokinetic-changes-during-pregnancy-according-to-genetic-variants-a-prospective-study-in-hiv-infected-patients-receiving-atazanavir-ritonavir
#2
Emanuele Focà, Andrea Calcagno, Andrea Bonito, Jessica Cusato, Elisabetta Domenighini, Antonio D'Avolio, Eugenia Quiros Roldan, Laura Trentini, Filippo Castelnuovo, Giovanni Di Perri, Francesco Castelli, Stefano Bonora
Atazanavir/ritonavir concentrations change over pregnancy in HIV-positive patients; the impact of genetic variants is unknown. 20 patients were enrolled: antiretrovirals' plasma and intracellular concentrations were measured in addition to single nucleotide polymorphisms in transport affecting genes. Linear logistic regression showed that genetic variants in organic-anion-transporter-1B1 and pregnane-X-receptor encoding genes affected third trimester atazanavir exposure. In this prospective study genetic variants partially explained the observed inter-patient variability in third-trimester antiretrovirals' exposure...
May 14, 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29759961/the-roles-of-xenobiotic-receptors-beyond-chemical-disposition
#3
Bryan Mackowiak, Jessica Hodge, Sydney Stern, Hongbing Wang
Over the past 20 years, the ability of the xenobiotic receptors to coordinate an array of drug-metabolizing enzymes and transporters in response to endogenous and exogenous stimuli has been extensively characterized and well documented. The constitutive androstane receptor (CAR) and the pregnane X receptor (PXR) are the xenobiotic receptors that have received the most attention, as they regulate the expression of numerous proteins important to drug metabolism and clearance and formulate a central defensive mechanism to protect the body against xenobiotic challenges...
May 14, 2018: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/29758112/novel-and-emerging-therapies-for-cholestatic-liver-diseases
#4
Jordan Goldstein, Cynthia Levy
While bile acids are important for both digestion and signaling, hydrophobic bile acids can be harmful especially when in high concentrations. Mechanisms for protection of cholangiocytes against bile acid cytotoxicity include negative feedback loops via farnesoid X nuclear receptor (FXR) activation, the bicarbonate umbrella, cholehepatic shunting and anti-inflammatory signaling, among others. By altering or overwhelming these defense mechanisms, cholestatic diseases such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) can further progress to biliary cirrhosis, end-stage liver disease and death or liver transplantation...
May 14, 2018: Liver International: Official Journal of the International Association for the Study of the Liver
https://www.readbyqxmd.com/read/29757018/a-current-structural-perspective-on-pxr-and-car-in-drug-metabolism
#5
Cameron D Buchman, Sergio C Chai, Taosheng Chen
Pregnane X receptor (PXR) and the constitutive androstane receptor (CAR) are two members of the nuclear receptor superfamily that play major roles in the expression of various drug metabolism enzymes and are known for their ligand promiscuity. As with other nuclear receptors, PXR and CAR are each composed of a ligand-binding domain (LBD) and a DNA-binding domain (DBD) connected by a hinge region. Areas covered: This review focuses on the information obtained over the last 15+ years from X-ray crystallography studies of the structure of PXR and CAR...
May 14, 2018: Expert Opinion on Drug Metabolism & Toxicology
https://www.readbyqxmd.com/read/29743477/biosynthetic-pathway-for-furanosteroid-demethoxyviridin-and-identification-of-an-unusual-pregnane-side-chain-cleavage
#6
Gao-Qian Wang, Guo-Dong Chen, Sheng-Ying Qin, Dan Hu, Takayoshi Awakawa, Shao-Yang Li, Jian-Ming Lv, Chuan-Xi Wang, Xin-Sheng Yao, Ikuro Abe, Hao Gao
Furanosteroids, represented by wortmannin, viridin, and demethoxyviridin, are a special group of fungal-derived, highly oxygenated steroids featured by an extra furan ring. They are well-known nanomolar-potency inhibitors of phosphatidylinositol 3-kinase and widely used in biological studies. Despite their importance, the biosyntheses of these molecules are poorly understood. Here, we report the identification of the biosynthetic gene cluster for demethoxyviridin, consisting of 19 genes, and among them 15 biosynthetic genes, including six cytochrome P450 monooxygenase genes, are deleted...
May 9, 2018: Nature Communications
https://www.readbyqxmd.com/read/29738703/high-fat-diet-induced-obesity-is-mitigated-in-cyp3a-null-female-mice
#7
Ramiya Kumar, Elizabeth J Litoff, W Tyler Boswell, William S Baldwin
Recent studies indicate a role for the constitutive androstane receptor (CAR), pregnane X-receptor (PXR), and hepatic xenobiotic detoxifying CYPs in fatty liver disease or obesity. Therefore, we examined whether Cyp3a-null mice show increased obesity and fatty liver disease following 8-weeks of exposure to a 60% high-fat diet (HFD). Surprisingly, HFD-fed Cyp3a-null females fed a HFD gained 50% less weight than wild-type (WT; B6) females fed a HFD. In contrast, Cyp3a-null males gained more weight than WT males, primarily during the first few weeks of HFD-treatment...
May 5, 2018: Chemico-biological Interactions
https://www.readbyqxmd.com/read/29736778/effects-of-polymorphisms-in-nr1i2-cyp3a4-and-abc-transporters-on-the-steady-state-plasma-trough-concentrations-of-bosutinib-in-japanese-patient-with-chronic-myeloid-leukemia
#8
Maiko Abumiya, Akiko Mita, Saori Takahashi, Tomoko Yoshioka, Yoshihiro Kameoka, Naoto Takahashi, Masatomo Miura
We investigated the effects of polymorphisms in NR1I2 (7635A>G, 8055C>T), CYP3A4 (20230G>A), ABCB1 (1199G>A, 1236C>T, 2677G>T/A, 3435C>T), and ABCG2 (421C>A) on the mean plasma trough concentrations (C0 ) of bosutinib at the steady-state in 30 Japanese patients with chronic myeloid leukemia. Bosutinib C0 values were monitored using high-performance liquid chromatography. The median coefficient of variation (CV) value of the bosutinib C0 for one patient (intrapatient) during bosutinib therapy was 25...
May 7, 2018: Medical Oncology
https://www.readbyqxmd.com/read/29733390/increase-in-tacrolimus-exposure-after-steroid-tapering-is-influenced-by-cyp3a5-and-pregnane-x-receptor-genetic-polymorphisms-in-renal-transplant-recipients
#9
Frank Stifft, Sander M J van Kuijk, Otto Bekers, Maarten H L Christiaans
Background: Tacrolimus, a drug for prevention of rejection after kidney transplantation, has a narrow therapeutic window and is metabolized by the cytochrome P540 3A (CYP3A) system. Tacrolimus exposure increases after steroid tapering in many patients. The pregnane X receptor (PXR)-a mediator for CYP3A-has a steroid receptor and might regulate CYP3A5 activity depending on single nucleotide polymorphisms (SNPs) of CYP3A5 or PXR. This may contribute to differences in tacrolimus exposure after steroid tapering...
May 3, 2018: Nephrology, Dialysis, Transplantation
https://www.readbyqxmd.com/read/29726713/structural-characterization-and-immunosuppressive-activity-of-a-new-pregnane-glycoside-from-epigynum-cochinchinensis
#10
Yu-Ting Shao, Yan Zhao, Hong Zhang, Meng-Jun Jiang, Afsar Khan, Sheng-Bao Cai, Tian-Rui Zhao, Gui-Guang Cheng, Jian-Xin Cao
Phytochemical investigation on the ethyl acetate fraction of the leaves of Epigynum cochinchinensis led to the isolation of a new C21 pregnane glycoside, epigycoside B (1), together with three known analogues. Their structures were elucidated on the basis of extensive spectroscopic techniques, including UV, MS, and NMR experiments, as well as the chemical methods. Compound 1 displayed in vitro immunosuppressive activity against concanavalin A (Con A)/Lipopolysaccharides (LPS)-stimulated proliferation of mice splenocyte...
May 4, 2018: Natural Product Research
https://www.readbyqxmd.com/read/29709908/effects-of-oridonin-on-hepatic-cytochrome-p450-expression-and-activities-in-pxr-humanized-mice
#11
Zhang Yi-Wen, Bao Mei-Hua, Lou Xiao-Ya, Cheng Yu, Yu Jing, Zhou Hong-Hao
Oridonin, the major terpene found in Rabdosia rubescens, is widely used as dietary supplement or therapeutic drug, while the effects of oridonin on CYP450 were still unclear. The pregnane X receptor (PXR) is an important regulatory factor for major drug metabolism enzyme CYPs, and it has been reported to have species-specific differences. Therefore, this study has employed more reliable models PXR-humanized mouse to investigate the influence of oridonin on PXR and downstream metabolism enzyme. Eight-week-old male PXR-humanized mice were treated with oridonin by orally (0, 25, 50, 100, 200 mg/kg) for 15 d...
2018: Biological & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/29703383/pxr-as-a-mediator-of-herb-drug-interaction
#12
REVIEW
Brett C Hogle, Xiudong Guan, M Maggie Folan, Wen Xie
Medicinal herbs have been a part of human medicine for thousands of years. The herb-drug interaction is an extension of drug-drug interaction, in which the consumptions of herbs cause alterations in the metabolism of drugs the patients happen to take at the same time. The pregnane X receptor (PXR) has been established as one of the most important transcriptional factors that regulate the expression of phase I enzymes, phase II enzymes, and drug transporters in the xenobiotic responses. Since its initial discovery, PXR has been implicated in multiple herb-drug interactions that can lead to alterations of the drug's pharmacokinetic properties and cause fluctuating therapeutic efficacies, possibly leading to complications...
April 2018: Journal of Food and Drug Analysis
https://www.readbyqxmd.com/read/29695968/neurosteroid-transport-in-the-brain-role-of-abc-and-slc-transporters
#13
REVIEW
Markus Grube, Paul Hagen, Gabriele Jedlitschky
Neurosteroids, comprising pregnane, androstane, and sulfated steroids can alter neuronal excitability through interaction with ligand-gated ion channels and other receptors and have therefore a therapeutic potential in several brain disorders. They can be formed in brain cells or are synthesized by an endocrine gland and reach the brain by penetrating the blood-brain barrier (BBB). Especially sulfated steroids such as pregnenolone sulfate (PregS) and dehydroepiandrosterone sulfate (DHEAS) depend on transporter proteins to cross membranes...
2018: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29691280/a-transcriptional-regulatory-network-containing-nuclear-receptors-and-lncrnas-controls-basal-and-drug-induced-expression-of-cytochrome-p450s-in-heparg-cells
#14
Liming Chen, Yifan Bao, Stephanie C Piekos, Kexin Zhu, Lirong Zhang, Xiao-Bo Zhong
Cytochrome P450 enzymes are responsible for metabolizing drugs. Expression of P450s can directly affect drug metabolism, resulting in various outcomes in therapeutic efficacy and adverse effects. Several nuclear receptors are transcription factors that can regulate expression of P450s at both basal and drug-induced levels. Some long non-coding RNAs (lncRNAs) near a transcription factor are found to participate in the regulatory functions of the transcription factors. The aim of this study is to determine whether there is a transcriptional regulatory network containing nuclear receptors and lncRNAs controlling both basal and drug-induced expression of P450s in HepaRG cells...
April 24, 2018: Molecular Pharmacology
https://www.readbyqxmd.com/read/29684404/previously-undisclosed-bioactive-sterols-from-corbiculid-bivalve-clam-villorita-cyprinoides-with-anti-inflammatory-and-antioxidant-potentials
#15
Minju Joy, Kajal Chakraborty
The estuarine Corbiculid bivalve black clam, Villorita cyprinoides collected from the Southwestern coastline regions of Arabian Sea are significant resources of nutritional and bioactive pluralities. The purification of ethyl acetate:methanol (EtOAc:MeOH) extract of V. cyprinoides characterized a previously undisclosed specialized abeo-pregnane-type sterol derivative 19 (10→5) abeo-20-methyl-pregn-10-en-3β-yl-hex-(3'E)-enoate (1) along with two cholestenols (22E),(241 E)-241 ,242 -dihomocholesta-5,22,241 -trien-3β-ol (2) and (22E)-241 -homocholesta-5,22-dien-(3β,241 β)-diol (3)...
April 20, 2018: Steroids
https://www.readbyqxmd.com/read/29682020/morphometric-analysis-of-dose-dependent-effect-of-progesterone-on-experimental-vasospasm-induced-rat-femoral-arteries
#16
Metin Kasap, Huseyin Canaz, Gokhan Canaz, Mehmet Tokmak, Alper Bingul, Ibrahim Alatas
Objective: Our aim of this study was to determine effective doses of progesterone which has a vasodilatory effect during the early stage of vasospasm. Cerebral vasospasm (CV) is a predominant cause of morbidity and mortality which develops following subarachnoidal hemorrhage (SAH). Etiopathogenesis of CV is multifactorial. Despite many previously performed studies on this issue, the mechanism by which blood and blood products in the subarachnoidal space induce CV has not been clarified yet...
April 2018: Asian Journal of Neurosurgery
https://www.readbyqxmd.com/read/29668912/ovine-placental-steroid-synthesis-and-metabolism-in-late-gestation
#17
Lawrence P Reynolds, Erin L Legacki, C Jo Corbin, Joel S Caton, Kimberly A Vonnahme, Scott Stanley, Alan J Conley
Steroid synthesis is required for pregnancy maintenance and for parturition but comparatively little is known about the major metabolic routes that influence circulating concentrations. Dietary intake changes progesterone and estradiol concentrations in pregnant ewes but whether this reflects placental synthesis is unknown. Progesterone metabolism by 5alpha-reduction is a major metabolic route in other species and can influence the onset of parturition. Therefore, studies were conducted to 1) determine placental enzyme activity, progesterone and estradiol measured by immuno-assay in late gestation ewes on low, moderate and high nutritional planes, 2) to assess the significance of 5alpha-reduction of progesterone in determining progesterone concentrations in late gestation ewes (gestation day 145) given finasteride to inhibit 5alpha-reductase metabolism...
April 14, 2018: Biology of Reproduction
https://www.readbyqxmd.com/read/29660500/occurrence-and-seasonal-variation-of-equine-estrogens-equilin-and-equilenin-in-the-river-water-of-japan-implication-with-endocrine-disrupting-potentials-to-japanese-medaka-oryzias-latipes
#18
Hiroshi Ishibashi, Masaya Uchida, Keisuke Yoshimoto, Yuta Imamura, Ryoko Yamamoto, Yoshinori Ikenaka, Masahito Kawai, Nobuhiro Ichikawa, Yuji Takao, Nobuaki Tominaga, Yasuhiro Ishibashi, Koji Arizono
In this study, we determined the concentration of equine estrogens, such as equilin (Eq) and equilenin (Eqn), in the river water collected from nine research stations in Hokkaido, Japan. The LC-MS/MS analysis revealed that Eq concentrations were 2.7 ± 6.7, 0.22 ± 0.12, and 1.2 ± 0.64 ng/L in Sep 2015, Feb 2016, and Jul 2016, respectively. Eqn had concentration levels similar to those of Eq. Comparison of the concentrations at nine research stations showed that seasonal variation was observed in the detected Eq and Eqn concentration levels...
April 13, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29650790/effect-of-endocannabinoid-oleamide-on-rat-and-human-liver-cytochrome-p450-enzymes-in-in-vitro-and-in-vivo-models
#19
Gabriela Dovrtelova, Ondrej Zendulka, Kristyna Noskova, Jan Jurica, Ondrej Pes, Jan Dusek, Alejandro Carazo, Iveta Zapletalova, Natasa Hlavacova, Petr Pavek
The endocannabinoid system is important for many physiological and pathological processes, but its role in the regulation of liver cytochromes P450 (CYPs) is still unknown. We studied the influence of the endocannabinoid oleamide on rat and human liver CYPs. Oleamide was administered i.p. to rats at doses of 0.1, 1 and 10 mg/kg/day for 7 days. The content and activity of key CYPs was evaluated in rat liver microsomes. Moreover, its interactions with nuclear receptors regulating CYP genes and serum levels of their ligands (prolactin, corticosterone, and free triiodothyronine) were tested in vitro CYP inhibition assays...
April 12, 2018: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/29627605/evaluation-of-bisphenol-a-influence-on-endocannabinoid-system-in-pregnant-women
#20
Monika Zbucka-Kretowska, Robert Zbucki, Ewa Parfieniuk, Maciej Maslyk, Urszula Lazarek, Wojciech Miltyk, Jan Czerniecki, Slawomir Wolczynski, Adam Kretowski, Michal Ciborowski
Bisphenol A (BPA) is a synthetic chemical widely used in the industry, which may potentially evoke negative effects on human health, especially on reproductive processes and fetal development. BPA has been reported to act on estrogen, estrogen-related, androgen, thyroid hormone, pregnane X, peroxisome proliferation-activated, and aryl hydrocarbon receptors. However, other potential mechanisms of BPA action on pregnancy cannot be excluded. Comprehensive evaluation of BPA effect on pregnant women can be performed by use of metabolomics...
March 30, 2018: Chemosphere
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