steroid 16 alpha hydroxylase

..The shift in transcription and translation of protein for maintenance of physiologic homeostasis to production of viral proteins and transgene product and their associated toxicity during viral infection may explain our observations...

..Nephrotoxicity caused by combination therapy is due to CsA elevating levels of SRL or by SRL itself. Concurrent administration of CsA and SRL in transplant patients should be performed with caution...

..Further studies in humans, especially in poor metabolizers of CYP2D6, will be required to confirm these findings...

..Gemfibrozil may also impair clearance of CYP2C19 and CYP1A2 substrates, but inhibition of other CYP isoforms is unlikely...

..We tested the hypothesis that experimental TIA induces expression of P450 2C11, an arachidonic acid epoxygenase that produces vasodilator epoxyeicosatrienoic acids, leading to increased tissue perfusion and reduced stroke damage...

..The comparison of induction effect of ivermectin in rat, mouflon and fallow deer also demonstrates the inter-species differences in inducibility of CYP enzymes...

..The rate of other metabolic routes mediated by CYP2D6 only corresponded to about one fifth of the CYP2D6 catalyzed N-demethylation rate...

..The present findings suggest that the addition of Hsa and Hlc to microsomal incubation media may yield enzyme kinetic estimates more comparable with in vivo results...

..These factors should be considered when this formulation is used as an in vitro model in human liver microsomal drug metabolism studies...

..e., hypothalamic) damage produced at the time of MSG exposure. The irreversibility of the P450 damage is described as resulting from secondary defects initially induced by the neuronal lesions...

..Because the products of AA epoxygenation have anti-inflammatory properties, this alteration may contribute to uncontrolled renal inflammation, which is a major cause of renal damage in dTGR...

..Co-administration of high doses of valproic acid with drugs that are primarily metabolized by CYP2C9 may result in significant drug interactions...

..CONCLUSIONS: Formation of HPPH from PPH is mediated exclusively by CYP2C9 and 2C19, with CYP2C9 playing the major role...

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..However, it appears that sulfaphenazole can be used as a selective inhibitor for rat CYP2C6. In addition, furafylline may also be a relatively selective inhibitor for rat CYP1A2...

..In light of typical SSRI blood levels observed in patients, this study also suggests that the risk of a SSRI-phenytoin interaction is highest with fluoxetine and norfluoxetine, and less likely with sertraline and paroxetine...

..The mAb system offers large potential for studies of cytochrome P450 function useful in drug discovery and reduces the possibility of adverse drug reactions due to polymorphisms and drug interactions...

..Thus, compound 11 (R(1) = NH(2), R(2) = (CH(2))(2)CH(CH(3))(2)) appears to be particularly interesting for that purpose as its IC(50) value for CYP 2C8 is low (3 microM) and 20-fold smaller than those found for CYP 2C9 and 2C19...

..P450 isoforms mediating sildenafil biotransformation differ substantially between humans and the male rat, thereby limiting the applicability of this species as a model for sildenafil metabolism and drug interactions in humans...

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..Species-related differences exist in the oxidations of limonenes in CYP2B subfamily in rats and humans...

..The in-vivo contribution of CYP2C19 to tolbutamide 4-methylhydroxylation appears to be minor in humans. This suggests that, at least in vivo, tolbutamide remains a selective probe for measuring CYP2C9 activity in humans...

..However, the effect is not observed in the presence of serum proteins. It is therefore unlikely that atovaquone would significantly inhibit SMX-HA formation in vivo...

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..However, genetics also controls the amount (or activity) of the enzymes. Sex-dependent differences have been demonstrated for several CYP isoenzymes and for UGT. Ethnicity also appears to play a role in the activity of these enzymes...

..The selectivity of CYP2C8 in catalyzing phosphonate O-deethylation indicates that coadministration of drugs that are metabolized by the same enzyme requires careful consideration...

..Thus, generalized predictions on the effect of simulated microgravity on drug metabolism cannot be made and the overall effect of spaceflight on individual enzymes should be investigated...

..These data show that CYP2C8 is the main hepatic isoform responsible for the metabolism of AQ. The specificity, high affinity, and high turnover make AQ desethylation an excellent marker reaction for CYP2C8 activity...

..These changes in GRF-induced, sexually dimorphic secretory growth hormone profiles and the accompanying decline in P450 expression levels may anticipate similar, but more profound, changes to occur during senescence...

..In addition, CYP1A1, although less efficient, was also able to oxidize the two flavonols. Thus, dietary flavonols are likely to undergo oxidative metabolism mainly in the liver but also extrahepatically...

..These S. typhimurium strains may be useful not only for predicting the metabolic activation of promutagens catalyzed by human CYP but also for identifying the CYP form involved...

..It was also demonstrated that the presence of two phenolic groups is not always associated with antioxidant activity...

..It was also demonstrated that the qg and amount of CYP are useful parameters in the PKCYP-test by constructing a physiologically-based pharmacokinetic model which was applied to the PKCYP-test...

..On the other hand, tolbutamide hydroxylation was markedly higher in chickens than in dogs...

..The possible clinical implications of this modulation are discussed...

..It is concluded that CYP2C11 is a male-specific hepatic microsomal vitamin D 25-hydroxylase that hydroxylates vitamin D2, vitamin D3, 1alphaOHD2, and 1alphaOHD3. CYP2C11 is also a vitamin D 24-hydroxylase...

..CYP2C38 and CYP2C40 were found in liver, brain, kidney, and intestine, with trace amounts in lung and heart, while CYP2C37 and CYP2C39 appeared to be liver specific...

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..Thus, CYP2C11/13 could associate with UGTs, but the affinity is assumed to be weaker than that of CYP2B/3As. These results suggest that there is isoform specificity in the interaction between P450s and UGTs...

..It is likely that functional changes occurring as a result of the Ile359Leu transition are responsible for the tolbutamide poor metabolizer phenotype...

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..2% and 99.0% similar in amino acid sequences, suggesting that they were virtually identical. CMF1a and CMF1b were different but 96.1% similar, and CMF3 was between 76% and 78% similar to other members of the rat P450IID family...

..To date, the two silencer elements and possibly also the HNF-1-like element are the only functional elements defined in the CYP2C11 gene, and it is conceivable that induction of the gene involves derepression of the silencer elements...

..These results suggest that nonylphenol inhibits human hepatic CYPs, especially CYP2C9 and CYP2C19, and steroidogenic CYP17 activities...

..Northern blots showed that P-45016 alpha in the rat liver is pretranslationally regulated by the growth hormone secretory pattern. Southern blots indicated that few genes belong to the same P-450 gene family as P-45016 alpha...

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..These results suggest that active oxygen produced by P450 oxidized genomic DNA and induction of P450 increased oxidative stress that may contribute to tumor initiation and promotion...

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..In addition, CYP2C8 gene expression was found to generate a variety of scrambled RNA molecules including species that contained repetitions of certain exons...

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..The main focus of this review is to summarize the properties of individual P450 in light of their catalytic activities to understand their physiological significance...

..Cytochrome P-450d is known to be a high spin haemoprotein...

..This relatively long period before P-450 15 beta and P-450 16 alpha mRNA induction is seen might indicate that protein factors mediating GH action are involved...

..The data discussed here suggest that therapy of RA patients may benefit from the use of nonaromatizable androgens and/or the use of aromatase inhibitors...

..No 16alpha-hydroxylase and no lyase activity for 17alpha-hydroxyprogesterone. Sequence analyses showed that there are 28 different amino acid residues between human and baboon CYP17, primarily in helices F and G and the F-G loop...

..In conclusion, NP causes gender-specific P450 induction and therefore exposure to NP may cause distinct pharmacological and toxicological effects in males compared to females...

..01-1000 nM. These results indicate that there are some metabolic interactions between cannabinoid and steroid metabolism and that the constituents showing estrogen-like activity exist in marijuana...

..5 mg/kg. These findings indicate that HDBB would have hepatic peroxisome proliferative activity, and the difference in susceptibility of male and female rats to this effect might lead to marked gender-related differences in HDBB toxicity...

..It appears, therefore, that the mouse P-450 gene families evolved through gene duplication and selective mutation to create new P-450s structurally as well as to establish novel regulatory elements for the gene expressions...

..These newly identified androgen-regulated genes will constitute very useful models for studying the nature of tissue-specific gene regulation by androgens...

..In conclusion, trimethoprim and sulfamethoxazole can be used as selective inhibitors of CYP2C8 and CYP2C9 in in vitro studies. In humans, trimethoprim and sulfamethoxazole may inhibit the activities of CYP2C8 and CYP2C9, respectively...

..0% decrease), possibly due to the increased intestinal CYP1A that resulted in increased intestinal metabolism and decreased gastrointestinal absorption of ipriflavone in NARs...

..The smaller residue allows more flexibility of movement in the active pocket than Leu, presenting both the C16 and C17 of progesterone to the iron-oxy complex...

..These findings with two monotopic ER hemoproteins, CYP2C11 and CYP3A4, and the polytopic ER protein HMGR attest to the remarkable mechanistic diversity of cellular proteolytic disposal of ER proteins...

..The model has also been successful in explaining the differences in substrate specificity between CYP2C9 and CYP2C19...

..62 +/- 0.4 mL/h per kilogram; P =.0001). CONCLUSIONS: Losartan, a CYP2C9 substrate, had no effect on the pharmacokinetics of phenytoin. However, phenytoin inhibited the CYP2C9-mediated conversion of losartan to E3174...

..Thus, exposure to continuously elevated circulating ghrelin may be responsible for the suppression of GH secretion reported in rats after prolonged starvation...

..Those data were compared with the results obtained in the current study with CYP2C9 in an attempt to elucidate one of the mechanisms by which CYP becomes immunogenic...

..CONCLUSION: MMC can inhibit the activities of CYP2D1/2, CYP2C11, and CYP1A2 in rat liver microsomes in vitro, but it showed no significant effect on the activities of the three isoenzymes in vivo...

..HPC and EETs reduced astrocyte cell death, and P450 epoxygenase inhibition prevented protection by HPC. We conclude that HPC induces tolerance in astrocytes, at least in part, via HIF-1alpha-linked upregulation of P450 2C11...

..We hypothesized that failure to gain body weight in the PCA rat was the consequence of low testosterone levels and will be reversed by 4-hydroxyandrostenedione, a specific aromatase inhibitor...

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..These results indicate that while the induction of CYP2C12 during ageing could be due, at least partially, to the enhanced HNF3beta expression, the decline of CYP2C11 is unlikely related to a decrease of STAT5 activation...

..Lipid deposition in livers of patients with the metabolic syndrome may necessitate dosage adjustments for toxic drugs, including CLZ...

..Thus, in addition to Mrp2 deficiency, differential expression of CYP isoforms and their potential impact on the metabolism and pharmacokinetics of compounds should be considered when interpreting data from these rat strains...

..This is the first study to demonstrate that conventional hemodialysis acutely improves altered CYP functional expression observed in rat hepatocytes incubated with uremic human serum...

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..Patients with these genetic variants have been shown to require lower maintenance doses of warfarin, but a direct association between CYP2C9 genotype and anticoagulation status or bleeding risk has not been established...

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..Sulfaphenazole was easily included in that model; its very high affinity for CYP 2C9 is due to a third structural feature, the presence of its NH2 function which binds to CYP 2C9 iron...

..This unique polymorphism in the canine CYP2C subfamily may be a source of variability in the metabolic clearance in dogs of xenobiotics that are metabolized by the cytochrome P450 2C subfamily of enzymes...

..Taken together, these data indicate that methapyrilene intoxication leads to mitochondrial disfunction and suggest a critical role for a loss of mitochondrial Ca2+ homeostasis in this model of hepatocyte death...

..However, these molecules could also be rationalized as being the products of trans splicing phenomena between distinct pre-mRNAs...

..Although CYP2C8 has been shown to be phenobarbital inducible, neither a barbiturate-responsive regulatory sequence (a Barbie box) nor a phenobarbital-responsive enhancer module (PBREM) was found within the upstream region analyzed...

..It also confirms the importance of knowledge of diet when studying xenobiotic metabolising enzymes, particularly in wild animals such as the brushtail possum...

..The results of the present study show that the pig appears to be a representative species for evaluation of vitamin D3 hydroxylases in other mammals, including man...

..Thus, the selective suppression of hepatic microsomal P450 by cyclosporine is not only dependent on the length of therapy, but also the dose administered...

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..In view of the role of this enzyme in the oxidation of many therapeutic agents, exposure to phosphorothioate pesticides may adversely affect drug elimination in humans...

..The physiological role of these enzymes in the metabolism of estradiol in relation to breast cancer is discussed...

..Thus, the predominant expression of testosterone 16 alpha-hydroxylase in male 129/J mice is regulated pretranslationally, presumably at the transcriptional level of the P-450(16) alpha gene...

..Both hormonal and genetic regulations were responsible for the different phenotypes occurring in adult male and female C57Bl/6J and 129/J mouse livers...

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..Our data indicate that the HPF1 elements in the rat CYP2C genes have limited functional importance and that HNF-4 is not a major trans-activator for any of these genes...

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..6. The data presented above do not reveal any relationship between P4502B11 induction and liver regeneration. The reason for such a change is unknown, therefore further investigation needs to be carried out...

..Experiments performed with human liver microsomes confirmed that tienilic acid 5-hydroxylase underwent a time-dependent inactivation (apparent t1/2 = 10 +/- 5 min) during 5-hydroxylation of tienilic acid...

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..This approach requires that selective agents be used for specific enzymes. However, selectivity of action has been poorly characterized in vivo...

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..The SOF Coordinating Center was funded for 5 years;SOF clinical centers for 3 years. In order to meet these aims, two years of support is requested for the SOF clinical centers. ..

..Our long-term objective is to substantially improve our understanding of the impact of aging and menopause on measures of hip size, structure, and strength in a well-characterized multiethnic cohort of mid-life women. ..

..The SOF Coordinating Center was funded for 5 years; SOF clinical centers for 3 years. In order to meet these aims, two years of support is requested for the SOF clinical centers. ..

..If our hypotheses are born out, this may lead to trials and recommendations about lifestyle, Vitamin D supplementation, or medication, to promote high levels of function late in life. ..

..Improved understanding of the biological mechanisms for these associations could lead to the development and testing of preventive intervention. ..

..Ultimately, the goal of the research is to personalize the use of medications in children by selecting the appropriate dose of the correct medication for individual patients. ..

..This knowledge will aid us in understanding, and hopefully preventing, a major cause of stroke. ..

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..Our investigations will provide vital new information defining mechanisms by which epoxygenase metabolites of astrocytes inhibit autoregulatory vasoconstriction of cerebral arteries. ..

..These studies could lead to a better understanding of the relationships between diet and cancer through identification of glycosphingolipids as important constituents of food. ..

..They will also determine if there is linkage between increased P450 w-hydroxylase activity in response to increasing transmural pressure and the cerebral vascular responses to changes in PO2. ..

..Our long-term objective is to substantially improve our understanding of the impact of aging and menopause on measures of hip size, structure, and strength in a well-characterized multiethnic cohort of mid-life women. ..

..We will determine how myogenic tone occurs and how it is regulated under normal and abnormal conditions to make sure there is enough blood flow to neurons so the brain can work properly. ..

..This information will have direct application to transplant patients and give clinicians needed information regarding the relationship between immunosuppressive therapy and the prediction of toxicity. ..

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