This is the first in vitro study to investigate gender-related differences in the regulation of human cytochrome P450 by the flavonoids. Activities of CYP2E1 and CYP3A were measured in the presence of quercetin, myricetin, or isorhamnetin in hepatic microsomal pools from male and female donors. Hydroxylation of p-nitrophenol (PNPH) was measured to determine CYP2E1 activity, and O-dealkylation of 7-benzyloxy-4-trifluoromethylcoumarin (BFC) was measured to determine CYP3A activity. Quercetin, but not myricetin or isorhamnetin, competitively inhibited PNPH activity in human recombinant cDNA-expressed CYP2E1 with the Ki=52.1±6.31μM. In the human microsomes, slight inhibition of PNPH activity by quercetin was not considered as physiologically relevant. Quercetin inhibited BFC activity in human recombinant cDNA-expressed CYP3A4 competitively with the Ki=15.4±1.52μM, and myricetin - noncompetitively with the Ki=74.6±7.99μM. The degree of inhibition by quercetin was similar between genders. Myricetin showed somewhat stronger inhibition in female pools, but the Ki values were higher than physiologically relevant concentrations. Isorhamnetin did not affect either PNPH or BFC activity. We concluded that observed inhibition of CYP2E1 and CYP3A by some flavonols were not gender-dependent.

• MeSH
• cytochrom P-450 CYP2E1 metabolismus   MeSH
• cytochrom P-450 CYP3A metabolismus   MeSH
• flavonoidy farmakologie   MeSH
• hydroxylace MeSH
• inhibitory cytochromu P450 CYP2E1 farmakologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• jaterní mikrozomy účinky léků   metabolismus   MeSH
• kumariny metabolismus   MeSH
• lidé MeSH
• nitrofenoly metabolismus   MeSH
• quercetin analogy a deriváty   farmakologie   MeSH
• sexuální faktory MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• benzen metabolismus   MeSH
• cytochrom P-450 CYP2E1 biosyntéza   genetika   účinky léků   MeSH
• imunoblotting MeSH
• jaterní mikrozomy chemie   metabolismus   MeSH
• lidé MeSH
• radioizotopy uhlíku diagnostické užití   MeSH
• Check Tag
• lidé MeSH

It has been shown in previous studies that liver HEP-G2 cells (human hepatocellular carcinoma) lose their ability to express active alcohol dehydrogenase (ADH) and cytochrome P450 2E1 (CYP2E1). Although both are ethanol-inducible enzymes, short-term exposure to ethanol does not cause any changes in expression or activity in cultured HEP-G2 cells. Therefore, we tested the effect of long-term exposure to ethanol on the expression and activity of both ADH and CYP2E1 in these cells. The expression of ADH and CYP2E1 was assessed at the mRNA and/or protein level using real-time PCR and Western blot analysis. Specific colorimetric assays were used for the measurement of ADH and CYP2E1 enzymatic activities. Caco-2 cells (active CYP2E1 and inactive ADH) were used as control cells. Significantly increased protein expression of ADH (about 2.5-fold) as well as CYP2E1 (about 1.6-fold) was found in HEP-G2 cells after long-term (12 mo) exposure to ethanol. The activity of ADH and CYP2E1 was also significantly increased from 12 ± 3 and 6 ± 1 nmol/h/mg of total protein to 191 ± 9 and 57 ± 9 nmol/h/mg of total protein, respectively. We suggest that the loss of activity of ethanol-metabolizing enzymes in cultured HEP-G2 cells is reversible and can be induced by prolonged exposure to ethanol. We are therefore able to reactivate HEP-G2 cells metabolic functions concerning ethanol oxidation just by modification of in vitro culture conditions without necessity of transfection with its side effect - enzyme overexpression.

• MeSH
• alkoholdehydrogenasa biosyntéza   genetika   MeSH
• apoptóza účinky léků   MeSH
• buňky Hep G2 MeSH
• cytochrom P-450 CYP2E1 biosyntéza   genetika   MeSH
• enzymová indukce účinky léků   MeSH
• ethanol farmakologie   MeSH
• hepatocelulární karcinom enzymologie   patologie   MeSH
• játra účinky léků   enzymologie   MeSH
• lidé MeSH
• nádory jater enzymologie   patologie   MeSH
• oxidace-redukce účinky léků   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Apigenin is a natural flavonoid compound that has antioxidative, anti-inflammatory, and hepatoprotective effects, but the underlying mechanisms are still unclear. In this study, the effects of apigenin on ethanol-induced oxidative stress and lipopolysaccharide (LPS)-induced inflammatory cytokine production were examined in cultured rat hepatocytes. Following pretreatment of ethanol-stimulated hepatocytes with apigenin 6–24 mM for 2 h, the levels of cytochrome P450 2E1 (CYP2E1) protein expression and supernatant alanine aminotransferase and malondialdehyde were reduced (P < 0.05 or P < 0.01), while the activities of glutathione reductase and glutathione peroxidase were increased (P < 0.05 or P < 0.01). Likewise, the pretreatment of LPS-stimulated hepatocytes with the same concentrations of apigenin could decrease the levels of nuclear factor-κB protein expression and supernatant tumor necrosis factor-α and interleukin-6 (P < 0.05 or P < 0.01), and increase the level of IκB-α protein expression (P < 0.05 or P < 0.01). In all of these results, the concentration of 24 μM was the most effective. These findings demonstrate that apigenin may exert an inhibitory effect on ethanol-induced oxidative stress and LPS-induced inflammation in the cultured hepatocytes, and its mechanisms may be related to the reduction of CYP2E1 expression, increment of antioxidative ability, and regulation of inflammatory gene expression.

• MeSH
• apigenin farmakologie   MeSH
• cytokiny metabolismus   MeSH
• ethanol metabolismus   MeSH
• hepatocyty imunologie   metabolismus   MeSH
• induktory cytochromu P450 CYP2E1 farmakologie   metabolismus   MeSH
• kultivované buňky MeSH
• lipopolysacharidy metabolismus   MeSH
• oxidační stres účinky léků   MeSH
• techniky in vitro MeSH
• zánět etiologie   metabolismus   MeSH
• Publikační typ
• práce podpořená grantem MeSH

OBJECTIVES: The aim of the study was to find whether probiotic Lactobacillus casei influences the expression or the activity of cytochromes P450 (CYP) and whether it has an influence on the level of CYP mRNA in male rats. DESIGN: Live bacterial suspension of L. casei was administered orally (gavage) to healthy male Wistar rats daily for 7 days. Control group of rats was treated with the saline solution. Sections of the duodenum, jejunum, ileum, caecum and colon were dissected from each experimental animal. In all individual samples, the expression of selected CYPs was determined by Western blotting. The levels of expression of CYPs were also evaluated by mRNA using the real-time PCR method. RESULTS: There were changes observed in the expression of CYP enzymes and in the CYP mRNA levels along the intestine after application of L. casei. The expression of CYP1A1 enzyme was found to be decreased in the proximal part of the jejunum and colon, CYP1A1 mRNA level was decreased in the distal part of the jejunum, ileum and caecum. Thus, the changes in CYP1A1 protein or mRNA were observed along the intestine of male rats. Similarly, a decreased expression of the caecal CYP2E1 mRNA and of the duodenal CYP3A9 mRNA after treatment of rats with L. casei was found. CONCLUSION: Probiotic L. casei might be able to contribute to prevention against colorectal cancer by decreasing levels of certain forms of xenobiotic-metabolizing enzymes; moreover, in general, there is a possibility of interactions with concomitantly taken pharmacotherapeutic agents.

• MeSH
• aktivace enzymů účinky léků   MeSH
• aromatické hydroxylasy genetika   metabolismus   MeSH
• cytochrom P-450 CYP2E1 genetika   metabolismus   MeSH
• cytochrom P-450 CYP3A genetika   metabolismus   MeSH
• cytochromy genetika   metabolismus   MeSH
• játra účinky léků   metabolismus   mikrobiologie   MeSH
• krysa rodu rattus MeSH
• Lactobacillus casei fyziologie   MeSH
• messenger RNA metabolismus   MeSH
• potkani Wistar MeSH
• probiotika farmakologie   MeSH
• regulace genové exprese enzymů účinky léků   MeSH
• steroid-16-alfa-hydroxylasa genetika   metabolismus   MeSH
• steroid-21-hydroxylasa genetika   metabolismus   MeSH
• střeva účinky léků   metabolismus   mikrobiologie   MeSH
• systém (enzymů) cytochromů P-450 genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH

This research demonstrated the protective effect and possible mechanism of the Sophora viciifolia extract (SVE) against acetaminophen-induced liver injury in mice. The levels of ALT and AST in the serum and antioxidant enzyme activity in the liver were measured. We used immunohistochemistry to detect CYP2E1, Nrf2, and Keap1 protein expression in the liver. The mRNA expression in the liver of TNF-α, NF-κB, and IL-6, Nrf2 and its downstream genes HO-1 and GCLC were measured by qRT-PCR. We found that SVE could decrease the ALT and AST levels, promote the activities of SOD, CAT, GSH-Px, and GSH, and ameliorate pathological liver lesions. SVE could down-regulate the mRNA expression of inflammatory factors and up-regulate Nrf2, HO-1 and GCLC. SVE reduced the protein expression of the CYP2E1 and increased the Nrf2 and Keap1. SVE has been shown to have a protective effect against APAP-induced liver injury, possibly through activation of the Keap1-Nrf2 pathway.

• MeSH
• antioxidancia farmakologie   MeSH
• chronické poškození jater způsobené chemickými látkami * MeSH
• cytochrom P-450 CYP2E1 genetika   metabolismus   MeSH
• faktor 2 související s NF-E2 genetika   metabolismus   MeSH
• KEAP-1 genetika   metabolismus   MeSH
• messenger RNA MeSH
• myši MeSH
• ovoce metabolismus   MeSH
• paracetamol * škodlivé účinky   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The total content of rat liver microsomal cytochrome P450 (CYP) significantly decreased after repeated i.p. administration of the antiviral agent tenofovir ((R)-9-[2-(phosphonomethoxy)propyl] adenine) and tenofovir disoproxil at a daily dose 25 mg/kg, although the content of liver microsomal protein did not change. The decrease of the CYP content was accompanied by concomitant increase of the amount of inactive CYP form, cytochrome P420. This effect was confirmed by a parallel study of the activities of selected CYP forms, CYP2E1 (p-nitrophenol hydroxylation) and CYP1A2 (7-ethoxyresorufin deethylation). The activity (expressed relatively to the protein content) of both CYP forms decreased significantly following the decrease of the total CYP. On the other hand, the CYP2E1 activity expressed relatively to the decreasing total CYP content remained unchanged. However, CYP1A2 activity also decreased when calculated relatively to the total native CYP content indicating lower stability of this form. Semiquantitative RT-PCR showed no significant changes in expression of major rat liver microsomal CYP forms after tenofovir treatment. In conclusion, repeated administration of tenofovir in higher doses led to significant decrease of the relative proportion of active liver microsomal CYPs accompanied by a conversion of these enzymes to the inactive form (CYP420) maintaining the sum of CYP proteins unchanged.

• Klíčová slova
• PMPA, Cytochrome P450, CYP2E1, CYP1A2,
• MeSH
• adenin analogy a deriváty   aplikace a dávkování   farmakologie   MeSH
• antivirové látky aplikace a dávkování   farmakologie   MeSH
• cytochrom P-450 CYP1A2 genetika   metabolismus   MeSH
• cytochrom P-450 CYP2E1 genetika   metabolismus   MeSH
• cytochromy metabolismus   MeSH
• denaturace proteinů MeSH
• down regulace MeSH
• financování organizované MeSH
• injekce intraperitoneální MeSH
• jaterní mikrozomy MeSH
• játra enzymologie   účinky léků   MeSH
• krysa rodu rattus MeSH
• messenger RNA metabolismus   MeSH
• organofosfonáty aplikace a dávkování   farmakologie   MeSH
• potkani inbrední LEW MeSH
• prekurzory léčiv aplikace a dávkování   farmakologie   MeSH
• tenofovir MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH

• MeSH
• cytochrom P-450 CYP2E1 * metabolismus   účinky léků   MeSH
• dieta MeSH
• ethanol * aplikace a dávkování   farmakologie   škodlivé účinky   MeSH
• exprese genu účinky léků   MeSH
• hypertriglyceridemie diagnóza   farmakoterapie   genetika   MeSH
• interpretace statistických dat MeSH
• játra enzymologie   metabolismus   MeSH
• laboratorní zvířata MeSH
• lidé MeSH
• metabolický syndrom * MeSH
• modely nemocí na zvířatech * MeSH
• potkani Wistar MeSH
• preklinické hodnocení léčiv * metody   přístrojové vybavení   statistika a číselné údaje   využití   MeSH
• silymarin * aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• cirkadiánní hodiny MeSH
• cirkadiánní rytmus * MeSH
• cytochrom P-450 CYP2E1 MeSH
• exprese genu MeSH
• genetická transkripce MeSH
• hepatocyty MeSH
• léková chronoterapie MeSH
• lékové interakce MeSH
• lidé MeSH
• paracetamol škodlivé účinky   MeSH
• péče orientovaná na pacienta MeSH
• proteiny CLOCK MeSH
• transkripční faktory ARNTL MeSH
• Check Tag
• lidé MeSH

Dihydromyricetin (DHM) is a natural flavonoid showing several health promoting effects such as protective activity during severe alcohol intoxication. The mechanism underlying the effects of DHM on alcohol metabolism is virtually unknown. The present paper is focused on clarifying the role of DHM in the liver alcohol elimination at its molecular level. First, impact of DHM on alcohol dehydrogenase (ADH) activity in vitro and the enzyme induction in vivo was examined. Neither the ADH activity nor the enzyme expression were influenced by DHM. Next, the effect of DHM during alcohol intoxication were studied on primary hepatocytes isolated from EtOH-premedicated and untreated rats. The viability of cells exposed to alcohol, estimated based on the released enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), was slightly affected by DHM. Although the expected hepatoprotective effect of DHM was not fully achieved, DHM (in a concentration manner) proved to reduce the level of ROS/RNS in hepatocytes. However, no change in the rate of alcohol metabolism in vivo was found when rats were administered with a single or repeated dose of ethanol supplemented with DHM. In conclusion, the proposed positive effect of DHM during alcohol intoxication has not been proven. Moreover, there is no effect of DHM on the alcohol metabolism. The "hoped-for" DHM hepatoprotective activity can be attributed to the reduction of ROS/RNS levels in cells.

• MeSH
• alkoholdehydrogenasa metabolismus   MeSH
• antioxidancia farmakologie   MeSH
• cytochrom P-450 CYP2E1 metabolismus   MeSH
• ethanol metabolismus   MeSH
• flavonoly farmakologie   MeSH
• hepatocyty účinky léků   metabolismus   MeSH
• játra účinky léků   metabolismus   MeSH
• kultivované buňky MeSH
• metabolická inaktivace MeSH
• nitrosativní stres účinky léků   MeSH
• oxidační stres účinky léků   MeSH
• potkani Wistar MeSH
• reaktivní formy dusíku metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH