Publications (94) View all
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Article: Regulation of multidrug resistance protein 2 (MRP2, ABCC2) expression by statins: involvement of SREBP-mediated gene regulation.
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ABSTRACT: Multidrug resistance protein 2 (MRP2, ABCC2) is localized to the apical membrane of hepatocytes and played an important role in the biliary excretion of a broad range of endogenous and xenobiotic compounds and drugs, such as pravastatin. However, the effects of statins on MRP2 in the liver and the precise mechanisms of their actions have been obscure. The goal of this study was to determine the regulatory molecular mechanism for statin-induced MRP2 expression in hepatocytes. In vitro and in vivo studies suggested that pitavastatin increased MRP2 expression. Pitavastatin promoted liver X receptor (LXR) α/β translocation from the cytosol to nuclei, resulting in LXR activation. Deletion and mutational analysis suggested that the potential a sterol regulatory element (SRE) played a major role in the observed modulation of MRP2 expression by pitavastatin. Furthermore pitavastatin increased the protein-DNA complex, and when SRE was mutated, stimulation of the protein-DNA complex by pitavastatin was decreased. It was demonstrated that pitavastatin upregulated MRP2 expression by an SREBP regulatory pathway in hepatocytes and that the actions of statins may lead to improve the biliary excretion of MRP2 substrates.International journal of pharmaceutics 04/2013; · 2.96 Impact Factor -
Article: Survey on the Attitudes of Pharmacy Students in Japan toward Doping and Supplement Intake.
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ABSTRACT: Doping is one of the most serious problems for athletes, and it is important that pharmacists have more interaction with athletes to ensure safer drug usage. Education is one of the most important roles of sports pharmacists, who are specialists regarding drug usage for athletes. We investigated pharmacy students' interests and comprehension regarding drug usage, doping and supplement intake by using the form of a questionnaire, since it is important to know how they understand these subjects as part of their greater educational program. The subjects were sophomore and junior pharmacy students at three universities. It was revealed that most of the students have negative images regarding doping violation, and they answered that they are familiar with doping. However, only sixteen percent of the students had attended lectures by specialists on doping. In addition, one third of pharmacy students did not know that some over-the-counter (OTC) drugs might contain doping substances. With regard to supplement intake, approximately two thirds of the respondents had an interest in and positive image of supplement intake. However, it was revealed that only one third of them recognized supplements as food, and their information regarding supplements was obtained from uncertain media. It was suggested that it is important for pharmacy students to have more opportunities to learn about what doping is. More education and enlightenment by sports pharmacists would be effective for pharmacy students as well as athletes, and it would help us to broaden the scope of what we can do for athletes and society.Biological & Pharmaceutical Bulletin 01/2013; 36(2):305-310. · 1.66 Impact Factor -
Article: Renal uptake of substrates for organic anion transporters Oat1 and Oat3 and organic cation transporters Oct1 and Oct2 is altered in rats with adenine-induced chronic renal failure.
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ABSTRACT: Chronic renal failure (CRF) leads to decreased drug renal clearance and glomerular filtration rate. However, little is known about renal tubular excretion and reabsorption in CRF. We examined transport activity of renal transporters using rats with adenine-induced CRF. We examined the effect of adenine-induced CRF on mRNA level, protein expression of transporters expressed in kidney by real-time polymerase chain reaction, and western blotting. In vivo kidney uptake clearances of benzylpenicillin and metformin, which are typical substrates for renal organic anion transporters Oat1 and Oat3 and organic cation transporters Oct1 and Oct2, respectively, were evaluated. Protein and mRNA expression levels of Oat1, Oat 3, Oct1, and Oct2 were significantly decreased in adenine-induced CRF rats. On the contrary, levels of P-glycoprotein and Mdr1b mRNA were significantly increased in adenine-induced CRF rats. The mRNA expression levels of Oatp4c1, Mate1, Urat1, Octn2, and Pept1 were significantly decreased. Kidney uptake clearance of benzylpenicillin and that of metformin were significantly decreased in adenine-induced CRF rats. Also, serum from CRF rats did not affect Oat1, Oat3, Oct1, and Oct2 function. In conclusion, our results indicate that adenine-induced CRF affects renal tubular handling of drugs, especially substrates of Oat1, Oat3, Oct1, and Oct2. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci.Journal of Pharmaceutical Sciences 12/2012; · 3.06 Impact Factor -
Article: Quantification of intact carboplatin in human plasma ultrafitrates using hydrophilic interaction liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.
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ABSTRACT: Carboplatin is a platinum agent that is used for treatment of non-small-cell lung cancer and ovarian cancer. A sensitive and selective analytical method for the quantification of carboplatin in human plasma ultrafiltrates using liquid chromatography-tandem mass spectrometry was developed. Human plasma ultrafiltrates were precipitated by acetonitrile containing carboplatin-d4 as an internal standard and were further diluted with acetonitrile. Chromatographic separation was performed on a Accucore HILIC (50mm×2.1mm i.d., 2.6μm) column using mobile phase (acetonitrile-water-acetic acid=90:10:0.1, v/v/v) at the flow rate of 0.2mL/min. Detection was performed on electrospray ionization triple quadrupole tandem mass spectrometer using low-energy collision induced dissociation (CID-MS/MS) analysis operating in the selected reaction monitoring (SRM) scan mode. The lower limit of quantification for carboplatin was 0.025μg/mL. This method covered a linearity range of 0.025-50μg/mL. The intra-day precision and inter-day precision (R.S.D.) ranged from 1.5 to 4.3%, and the accuracy (R.E.) was within ±2.9%. The present method was applied to a clinical pharmacokinetic study of carboplatin in a cancer patient.Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 12/2012; 917-918C:18-23. · 2.78 Impact Factor -
Article: The Decrease in Farnesoid X Receptor, Pregnane X Receptor and Constitutive Androstane Receptor in the Liver after Intestinal Ischemia-Reperfusion.
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ABSTRACT: Purpose. Intestinal ischemia-reperfusion (I/R) damages remote organs, including the liver, and promotes multi-organ failure (MOF). However, the molecular mechanisms underlying acute liver injury after intestinal I/R have not been completely elucidated. Farnesoid X receptor (FXR), pregnane X receptor (PXR) and constitutive androstane receptor (CAR) regulate metabolizing enzymes and transporters, and coordinately prevent hepatotoxicity reflecting an inability of appropriate excretion of endogenous toxic compounds. In this study, we assessed FXR, PXR and CAR expression levels and their localization levels in nuclei in the liver after intestinal I/R. We also investigated the effect of IL-6 on FXR, PXR and CAR expression levels and their localization levels in nuclei in in vitro experiments. Methods. We used intestinal I/R model rats. Moreover, HepG2 cells were used in in vitro study. Real-time PCR and Western blotting were used to assess mRNA and protein expression levels. Nuclear receptor localization in nuclei was analyzed by Western blotting using nuclear extracts. Results. FXR and PXR expression levels began to be decreased at 3 h, and FXR, PXR and CAR expression levels were decreased at 6 h after intestinal I/R. The localization levels of FXR, PXR and CAR in nuclei began to be decreased at 3 h, and all of them were decreased at 6 h after intestinal I/R. In HepG2 cells, FXR, PXR and CAR expression levels were decreased by 0.5-1 ng/mL, 0.5-100 ng/mL and 100 ng/mL IL-6 treatment for 24 h, respectively. FXR, PXR and CAR localization levels in nuclei were suppressed by 0.5-10 ng/mL, 10-100 ng/mL and 10-100 ng/mL IL-6 treatment for 24 h, respectively. Conclusions. FXR, PXR and CAR expression levels are decreased in the liver after intestinal I/R. IL-6 is one of main causes the decreases in expressions of these receptors. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.Journal of pharmacy & pharmaceutical sciences: a publication of the Canadian Society for Pharmaceutical Sciences, Societe canadienne des sciences pharmaceutiques 12/2012; 15(5):616-631. · 1.65 Impact Factor
