Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The subchronic toxicity of the aqueous antidiabetic herbal extract ADD-199, prepared from Maytenus senegalensis, Annona senegalensis, Kigelia africana and Lanneawelwitschii, and administered at a daily dose of 100 or 500 mg/kg body weight over 30 days, was investigated in male Wistar albino rats. Certain haematological, urine and plasma biochemical parameters, and modulation of some hepatic cytochrome P450 (CYP) isozymes were measured as indices of organ specific toxicity or potential for drug interactions. ADD-199 did not affect plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and albumin or creatinine kinase (CK) levels. It also did not affect plasma creatinine and urea levels. Furthermore, ADD-199 neither affected PCV nor blood Hb, RBC, reticulocytes, platelets, lymphocytes and granulocyte levels. It, however, caused significant dose-dependent reductions in WBC counts at day 15 with varying degrees of recovery by day 30. It also reduced the rate of body weight increases after week 3. However, no changes were observed in organ weights at termination. ADD-199 did not significantly affect zoxazolamine-induced paralysis and pentobarbital-induced sleeping times as well as certain CYP isozyme activities in rats. These findings suggest that ADD-199 had no overt organ specific toxicity and did not demonstrate a potential for drug interactions via CYP-mediated metabolism in the rat on subchronic administration.
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PMID:Subchronic toxicity studies of the antidiabetic herbal preparation ADD-199 in the rat: absence of organ toxicity and modulation of cytochrome P450. 1570 72

The role of cytochrome P450 activity in the nephrotoxicity of chlorotrifluoroethylene (CTFE) and 1,1-dichloro-2,2-difluoroethylene (DCDFE) was investigated in the male rat. Hepatic cytochrome P450 1A1 and principally P450 2B1/2 were induced by beta-naphthoflavone and phenobarbital, respectively. Nephrotoxicity was evaluated by investigating urine biochemical parameters, kidney histochemistry and histopathological modifications. Both CTFE and DCDFE induce severe nephrotoxicity in rats after 4 h of exposure to 200 and 100 ppm, respectively. Compared with controls, activity levels of gamma-glutamyltranspeptidase (gamma GT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and N-acetyl-beta-D-glucosaminidase (NAG) in 24-h urine were increased similarly, but urinary excretion of glucose, proteins and beta2-microglobulin (beta2-m) and serum urea and creatinine levels were increased. Histopathological and histochemical examinations of kidney sections of CTFE- and DCDFE-exposed rats revealed cellular necrosis and tubular lesions 24 h after exposure. Beta-naphthoflavone-pretreated rats were afforded some protection against the nephrotoxicity of CTFE and DCDFE. Phenobarbital did not modify DCDFE nephrotoxicity but afforded some protection against CTFE nephrotoxicity. In conclusion, CTFE and DCDFE are strong nephrotoxins. Cytochrome P450 1A1 is implicated in CTFE and DCDFE metabolism and one or several cytochromes induced by phenobarbital are implicated in CTFE metabolism. The P450 cytochromes involved in CTFE and DCDFE metabolism probably constitute detoxication metabolic pathways. The nephrotoxicity of CTFE and DCDFE is therefore subordinated to the cytochrome P450 activity involved in their metabolism.
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PMID:Effect of beta-naphthoflavone and phenobarbital on the nephrotoxicity of chlorotrifluoroethylene and 1,1-dichloro-2,2-difluoroethylene in the rat. 1574 58

Progesterone receptor (PR) agonists have several important applications in women's health, such as in oral contraception and post-menopausal hormone therapy. Currently, all PR agonists used clinically are steroids. Because of their interactions with other steroid receptors, steroid-metabolizing enzymes, or other steroid-signaling pathways, these drugs can pose significant side effects in some women. Efforts to discover novel nonsteroidal PR agonists with improved biological properties led to the discovery of tanaproget (TNPR). TNPR binds to the PR from various species with a higher relative affinity than reference steroidal progestins. In T47D cells, TNPR induces alkaline phosphatase activity with an EC(50) value of 0.1 nm, comparable with potent steroidal progestins such as medroxyprogesterone acetate (MPA) and trimegestone (TMG), albeit with a reduced efficacy ( approximately 60%). In a mammalian two-hybrid assay to measure PR agonist-induced interaction between steroid receptor co-activator-1 and PR, TNPR showed similar potency (EC(50) value of 0.02 nm) and efficacy to MPA and TMG. Importantly, in key animal models such as the rat ovulation inhibition assay, TNPR demonstrates full efficacy and an enhanced progestational potency (30-fold) when compared with MPA and TMG. Furthermore, TNPR has relatively weak interactions with other steroid receptors and binding proteins and little effect on cytochrome P450 metabolic pathways. Finally, the three-dimensional crystal structure of the PR ligand binding domain with TNPR has been delineated to demonstrate how this nonsteroidal ligand achieves its high binding affinity. Therefore, TNPR is a structurally novel and very selective PR agonist with an improved preclinical pharmacological profile.
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PMID:Molecular and pharmacological properties of a potent and selective novel nonsteroidal progesterone receptor agonist tanaproget. 1593 32

A hydroalcoholic (50%) extract of Emblica officinalis (fruit) (EO-50) reduced the severity of hepatic fibrosis induced by carbon tetrachloride (CCl4) and thioacetamide (TAA). Improved liver function was observed by measuring the levels of aspartate aminotransaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin in serum. Hepatic parameters monitored were the levels of glutathione (GSH), lipid peroxidation (LPO) and hydroxyproline and the activities of catalase, glutathione peroxidase (GPx), Na+,K+-ATPase and cytochrome P450 (CYP 450 2E1) (aniline hydroxylation). The results suggested that EO-50 effectively reversed profibrogenic events possibly due to its promising antioxidative activity.
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PMID:Reversal of fibrogenic events in liver by Emblica officinalis (fruit), an Indian natural drug. 1599 20

The alveolar epithelium may function as a barrier for airborne xenobiotics, and in vitro models mimicking this barrier are useful for metabolism and toxicity studies. To gain insight into the metabolic competence of alveolar epithelial cells (AECs), we investigated transcript expression of 10 different cytochrome P450 monooxygenases as well as expression of surfactant proteins A to D. We also investigated gene expression of the transcription factors PCNA, TTF-1, HNF3beta , GATA-6, C/EBPalpha and C/EBPdelta which drive, at least in part, development and differentiation of alveolar epithelium. We further studied the metabolism of testosterone, a substrate for cytochrome P450 (CYP) monooxygenases, in cultures of AECs. Essentially, medium supplementation with 5% rat serum, as opposed to 10% FCS, promoted a high level of differentiation, as judged by the mRNA expression of CYP monooxygenases, e.g. 1A1, 1A2, 2B1 and 2J3, the expression of the surfactant proteins A, B, and C, the immunohistochemical staining for surfactant protein C, and staining for alkaline phosphatase activity. Further, AECs, when cultured in the presence of 5% rat serum, promoted metabolic competence, as evidenced by the fingerprinting of individual testosterone metabolites. We thus characterized AECs in culture and found these respiratory epithelial cells to express an array of differentiation markers and showed these cultures to be metabolically competent under optimized culture conditions.
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PMID:Primary rat alveolar epithelial cells for use in biotransformation and toxicity studies. 1632 67

Administration of drugs by inhalation opens new possibilities for entry into the systemic circulation and cultures of porcine pulmonary epithelial cells (PECs) may prove to be valuable in the prediction of pulmonary metabolism of drugs in humans. This paper, therefore, reports a method for the routine isolation and cultivation of PECs from slaughterhouse animals. On average 1.5x10(6) cells g-1 tissue were isolated by discontinuous density-gradient centrifugation. Cells were subsequently cultivated on collagen-coated plates and characterized by staining for alkaline phosphatase, by tannic acid staining of lamellar bodies and by surfactant protein (SP) expression at days 0, 3 and 6 in culture. Over 70% of purified cells were positive for SP-C and tannic acid staining and thus defined as epithelial cells of alveolar origin (AECs). The AEC phenotype was also confirmed by specific binding of marker lectins (Maclura pomifera and Helix pomatia) and by studying gene expression and activity of cytochrome P450 monooxygenases. Testosterone, ethoxyresorufin, benzyloxyresorufin and verapamil were used as substrates for cytochrome P450-catalysed oxidations and cultured cells were found to be differentiated as well as metabolically competent during cultivation. Therefore, this culture system enables in depth pulmonary biotransformation and toxicity studies.
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PMID:Isolation and characterization of metabolically competent pulmonary epithelial cells from pig lung tissue. 1639 53

The liver plays an important role in the modulation of the process of carcinogenesis, as it is the primary site for the biotransformation of xenobiotics including carcinogens as well as anticancer drugs. The present study was designed to evaluate the biochemical alterations occurring in the liver of 7,12-dimethylbenz(a)anthracene (DMBA) induced skin tumor bearing male Balb/c mice and their modulation by aqueous Azadirachta indica leaf extract (AAILE). It was observed that skin tumor induction caused hepatic damage characterized by a decreased hepatosomatic index and significantly increased (p < 0.001) activities of the hepatic tissue injury marker enzymes, namely alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase. However, upon treatment with AAILE, the above-mentioned alterations, including the increased activities of hepatic tissue injury marker enzymes, were significantly reversed, which signified the hepato-protective efficacy of Azadirachta indica. Increased oxidative stress was also observed in the hepatic tissue of skin tumor bearing mice as revealed by a significant increase (p < 0.001) in lipid peroxidation levels and a decrease in reduced glutathione contents and activities of various antioxidant enzymes studied, namely glutathione-S-transferase, glutathione peroxidase and glutathione reductase. The AAILE treatment reduced oxidative stress by decreasing lipid peroxidation levels and enhancing the reduced glutathione contents and activities of various antioxidant enzymes. The activities of the xenobiotic biotransformation enzymes, namely cytochrome P450, cytochrome b5 and glutathione-S-transferase, were found to be decreased in the hepatic tissue of tumor bearing mice. Treatment with AAILE further caused a decrease in the activity of cytochrome P450 and cytochrome b5, whereas it up-regulated the activity of glutathione-S-transferase. The significance of these observations with respect to the progress of the process of carcinogenesis is explained in the present research article.
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PMID:Chemomodulatory effects of Azadirachta indica on the hepatic status of skin tumor bearing mice. 1652 Nov 6

Human cerebral malaria is caused by a protozoan parasitic with no cure till date. The isolation of brain capillaries i.e. microvessels has permitted the in vitro study related to cerebral function. Microvessels were isolated from normal and P. yoelii infected mice brain cortex and subjected to biochemical characterization by the following enzyme markers viz alkaline phosphatase, gamma-glutamyI transpeptidase and monoamine oxidase and electron microscopically. Limited studies have been carried out in relation to drug metabolizing enzymes in cerebral microvessels of rodents. The present studies have been carried out in relation to status of drug metabolizing enzymes during P. yoelii infection in cerebral microvessels of mice. The data obtained depicted a clear cut impairment of cytochrome P450 (a terminal monooxygenase) and related indices viz b5, benzopyrene hydroxylase, aminopyrene-n-demethylase, aniline hydroxylase except NADH cytochrome e reductase which increased during P. yoelii infection in mice as compared to normal. Further the oral drug administration (arteether) treatment brought back the altered MFO system normal a week alter cessation of drug treatment.
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PMID:Studies on drug metabolizing enzymes during arteether treatment of Plasmodium yoelii nigeriensis infected mice cerebral microvessels. 1663

Itraconazole and fluconazole are potent wide spectrum antifungal drugs. Both of these drugs induce hepatotoxicity clinically. The mechanism underlying the hepatotoxicity is unknown. The purpose of this study was to investigate the role of phenobarbital (PB), an inducer of cytochrome P450 (CYP), and SKF 525A, an inhibitor of CYP, in the mechanism of hepatotoxicity induced by these two drugs in vivo. Rats were pretreated with PB (75 mg/kg for 4 days) prior to itraconazole or fluconazole dosing (20 and 200 mg/kg for 4 days). In the inhibition study, for 4 consecutive days, rats were pretreated with SKF 525A (50 mg/kg) or saline followed by itraconazole or fluconazole (20 and 200 mg/kg) Dose-dependent increases in plasma alanine aminotransferase (ALT), gamma-glutamyl transferase (gamma-GT), and alkaline phosphatase (ALP) activities and in liver weight were detected in rats receiving itraconazole treatment. Interestingly, pretreatment with PB prior to itraconazole reduced the ALT and gamma-GT activities and the liver weight of rats. No changes were observed in rats treated with fluconazole. Pretreatment with SKF 525A induced more severe hepatotoxicity for both itraconazole and fluconazole. CYP 3A activity was inhibited dose-dependently by itraconazole treatment. Itraconazole had no effects on the activity of CYP 1A and 2E. Fluconazole potently inhibited all three isoenzymes of CYP. PB plays a role in hepatoprotection to itraconazole-induced but not fluconazole-induced hepatotoxicity. SKF 525A enhanced the hepatotoxicity of both antifungal drugs in vivo. Therefore, it can be concluded that inhibition of CYP may play a key role in the mechanism of hepatotoxicity induced by itraconazole and fluconazole.
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PMID:Involvement of phenobarbital and SKF 525A in the hepatotoxicity of antifungal drugs itraconazole and fluconazole in rats. 1677 3

Previous reports have demonstrated that an intestinal injury causes hypofunctions of the liver associated with down-regulations of cytochrome P450, but an influence on hepatic transporters remains unclear. Here, we tested hepatic transporter functions in a rat model of bowel injury using indomethacin (IDM). After administration of IDM (8.5 mg/kg, i.p., 3 d), the rats suffered the intestinal impairment indicated by a reduction of alkaline phosphatase activity in mucosa. In vivo pharmacokinetic experiments of bromosulfophthalein (BSP) showed that there was a reduction in its plasma elimination rate and cumulative biliary excretion in IDM-treated rats and systemic and biliary clearances reduced to nearly 50% of the control group. Protein expressions in plasma membrane and mRNA levels of organic anion transporting polypeptide 1b2 (Oatp1b2) and multidrug resistance-associated protein 2 (Mrp2), which play hepatic BSP uptake and biliary excretion, respectively, in the liver were significantly reduced following the IDM treatment. In portal plasma, the levels of proinflammatory cytokines were unchanged, while the level of nitric oxide metabolites (NO2- + NO3-) increased to 6.5-fold that of the control. The time-course on IDM treatment indicated that, firstly, intestinal injury was induced, the NO level increased, and the hepatic Oatp1b2 and Mrp2 expression began to fall followed by an increase in plasma ALT. In conclusion, IDM-induced injury to the small intestine causes the hypofunction of hepatic Oatp1b2 and Mrp2 independently on the hepatic impairment, and NO arising from bowel injury may be one of key factors for it through the remote effect.
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PMID:Down-regulation of hepatic transporters for BSP in rats with indomethacin-induced intestinal injury. 1732 56


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