Search results for: Rabbit Anti-Human CYP1A2 Antibodies
#21458012 
2011/03/31
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Cross-sectional study of hepatic CYP1A and CYP3A enzymes in hybrid striped bass, channel catfish and Nile tilapia following oxytetracycline treatment.
Terramycin for Fish® (oxytetracycline, OTC) is one of three approved drugs for therapeutic treatment of fish in the United States. Nothing is known, however, of the effects of this therapeutic on drug metabolizing enzymes in fish post-treatment. The main purpose of the study was to examine whether the fish CYP1A and CYP3A enzymes would cross-react with antibodies to known mammalian cytochrome P-450 forms (CYP1A1 and CYP3A). Observational feeding studies of OTC effects were conducted in hybrid striped bass, channel catfish and Nile tilapia. Oxytetracycline was mixed into the feed to achieve a daily dose of 82.8 mg per kg body weight at a feeding rate of 1% body weight per day. Hepatic microsomes of each fish were prepared and Western blotting of CYP1A1 and CYP3A4 and enzyme assays of CYP1A2 and CYP3A4 were performed prior to OTC treatment and on post-treatment days 1, 6, 11 and 21. Both goat anti-rat CYP1A1 and rabbit anti-human CYP3A4 showed good cross-reactivity with all three species in this study. All three species exhibited distinct perturbations in one or more of the variables examined on day 1 post-treatment. Immediately following the 10-day medication period, relative liver weight (RLW) of hybrid striped bass was increased 44% and remained elevated through post-treatment day 21. Increased CYP3A4 enzyme activity and protein abundance were noted in channel catfish and Nile tilapia, respectively. This observational approach demonstrated species differences both in control activities and in the timing and extent of hepatic responses to OTC. The unique perturbations of hepatic CYP450 enzymes in different fish species to OTC treatment observed in this study may have relevance for the use of additional antibiotics or other therapeutics used in aquaculture.N Topic Popovic, T Howell, J G Babish, P R Bowser
2061 related Products with: Cross-sectional study of hepatic CYP1A and CYP3A enzymes in hybrid striped bass, channel catfish and Nile tilapia following oxytetracycline treatment.
25 mg1 Product tipe: Instrumen1000 TESTS/0.65ml10 mg100ug200 500 mg 5 G 5 G100ul25 mg0.1 mg
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#17728539 2007/08/29
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Observational study of hepatic cytochrome P-450 protein expression and activity in summer flounder (Paralichtys dentatus) after combination ormetoprim-sulfadimethoxine treatment.
The metabolism of aquaculture antibiotics on the piscine, hepatic cytochrome P-450 (CYP) system has not yet been defined. Fifty summer flounder, maintained at 20 degrees C, were fed ormetoprim-sulfadimethoxine (Romet-30(R)) at 1% body weight daily and were randomly sampled before treatment and on days 1, 6, 10 and 21 after treatment. Western blotting of hepatic microsomes included goat antirat CYP1A1 and rabbit antihuman CYP3A4 serum. Catalytic activities comprised: 3-cyano-7-ethoxycoumarin (CEC), 7-benzyloxy-4-trifluoromethylcoumarin (BFC), resorufin benzyl ether (BzRes). Treatment induced CYP1A1 and CYP3A4 expression. Dealkylation of CEC (CYP1A2) was increased after treatment. Romet-30 inhibited CYP3A4 activity measured by BFC, but induced BzRes CYP3A4. The usefulness of mammalian antibodies for piscine P-450 Western blotting was demonstrated. The hepatic P-450 1A2 and 3A4 metabolism was quantifiable by kits developed for mammalian microsomes.Natalija Topic Popovic, John G Babish, Paul R Bowser
1733 related Products with: Observational study of hepatic cytochrome P-450 protein expression and activity in summer flounder (Paralichtys dentatus) after combination ormetoprim-sulfadimethoxine treatment.
100ug Lyophilized100ug Lyophilized1 Set1 Set1 Set1 Set10050 100ug Lyophilized1 mg1mg1 Set
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#15618705 //
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Species differences in the metabolism of (+)- and (-)-limonenes and their metabolites, carveols and carvones, by cytochrome P450 enzymes in liver microsomes of mice, rats, guinea pigs, rabbits, dogs, monkeys, and humans.
(+)-Limonene is shown to cause renal toxicity in male rats, but not in female rats and other species of animals including mice, guinea pigs, rabbits, and dogs. We have previously shown that male-specific rat CYP2C11 (but not female-specific CYP2C12) is able to convert limonenes to carveols and perillyl alcohols (M. Miyazawa, M. Shindo, and T. Shimada: Chem. Res. Toxicol., 15, 15-20, 2002). Here, we investigated whether (+)- and (-)-limonene enantiomers are differentially metabolized by P450 enzymes in liver microsomes of mice, rats, guinea pigs, rabbits, dogs, monkeys, and humans. Limonene enantiomers were converted to respective carveols, perillyl alcohols, and carvones (oxidative metabolites of carveols) by liver microsomes of dogs, rabbits, and guinea pigs. Mice, rats, monkeys, and humans produced carveols and perilly alcohols, but not carvones. Reconstituted monooxygenase systems containing purified rabbit CYP1A2 and 2B4 and NADPH-P450 reductase were found to catalyze (+)-limonene to (+)-carveol, (+)-carvone, and (+)-perillyl alcohol, being more active with CYP2B4. When (+)-carveol and (+)-carvone were used as substrates, dogs, rabbits, and guinea pigs metabolized them to (+)-carvone and (+)-carveol, respectively. Again humans, monkeys, rats, and mice did not convert (+)-carveol to (+)-carvone, but metabolized (+)-carvone to (+)-carveol, with male rats having the highest rates. CYP2C enzymes were suggested to play major roles in metabolizing (+)-carveol to (+)-carvone and (+)-carvone to (+)-carveol by liver microsomes, since the activities were inhibited significantly by anti-human CYP2C9 antibodies in these animal species. Studies with recombinant P450 enzymes suggested that CYP2C9 and 2C19 in humans and CYP2C11 in untreated male rats were the major enzymes in metabolizing (+)-carvone. These results suggest that there are species-related differences in the metabolism of limonenes by P450 enzymes, particularly in the way from (+)-carveol to (+)-carvone. However, it remains unclear whether these differences in limonene metabolism by these animal species explain species-related differences in limonene-induced renal toxicity.Tsutomu Shimada, Masaki Shindo, Mitsuo Miyazawa
2005 related Products with: Species differences in the metabolism of (+)- and (-)-limonenes and their metabolites, carveols and carvones, by cytochrome P450 enzymes in liver microsomes of mice, rats, guinea pigs, rabbits, dogs, monkeys, and humans.
50 ug 50 ug 50 ug 96T10 mg200ug10 mg100 mg100ug1 mg1000 tests
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#11370663 //
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Induction of CYP1A by benzo[k]fluoranthene in human hepatocytes: CYP1A1 or CYP1A2?
While fresh human hepatocyte cultures are widely used to model hepatic cytochrome P450 (CYP) regulation and activity, their CYP1A subfamily composition induced by, e.g., polycyclic aromatic hydrocarbons is ambiguous. CYP1A1, CYP1A2, or both have been reported to be expressed, and their varied roles in chemical carcinogenesis makes resolution of which CYPs are expressed essential. We have used an immunoblot system with Bis-Tris-HCl-buffered polyacrylamide gel, which clearly resolves human CYP1A1 and CYP1A2, and polyclonal goat anti-human CYP1A1/CYP1A2 and rabbit anti-human CYP1A2 antibodies to probe the expressed CYP1A1 and CYP1A2 composition of seven individual human hepatocyte cultures induced with 5 microM benzo[k]fluoranthene (BKF) for 24 h. In six of the cultures only CYP1A1 was detected, and in the seventh both CYPs were detected. In most vehicle-treated hepatocyte cultures, neither CYP1A1 nor CYP1A2 was detected. In three additional hepatocyte cultures treated individually with BKF and 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD), the resultant induced CYP1A1/1A2 profiles were essentially not influenced by the nature of the inducing agents. To develop an activity-based assay to differentiate between CYP1A1 and CYP1A2 expression in human hepatocytes, our previously published R warfarin assay (Drug Metab. Disp. (1995) 23, 1339-1345) was applied to TCDD (10 nM)-treated hepatocyte culture. The low concentration of TCDD did not produce inhibition of the warfarin metabolism-such inhibition could confound the results. Based on the ratios of 6- to 8-hydroxywarfarin formed in two cultures, the ratios of CYP1A1/CYP1A2 expressed in these cultures were determined and they agreed with the ratios determined by immunoblot analysis. Thus each individual human hepatocyte culture must be characterized for induced CYP1A1 and CYP1A2 expression in studies of CYP1A activity. The warfarin assay provides a means of characterizing the cultures.N Liu, Q Y Zhang, D Vakharia, D Dunbar, L S Kaminsky
2136 related Products with: Induction of CYP1A by benzo[k]fluoranthene in human hepatocytes: CYP1A1 or CYP1A2?
50 50 100 μg50 100 μg100 μg10 100μg
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#1588920 //
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Characterization of human lung microsomal cytochrome P-450 1A1 and its role in the oxidation of chemical carcinogens.
Rat and human lung microsomal cytochrome P-450 (P-450) enzymes have been characterized with regard to their catalytic activities towards several xenobiotic chemicals, including procarcinogens, in different microsomal preparations. Rat lung microsomal P-450s were more active than the human P-450s in catalyzing most of the monooxygenation reactions. Human lung microsomal P-450 was solubilized and purified. Human lung microsomes contain approximately 10 pmol of P-450/mg of protein, on the basis of Fe2+.CO versus Fe2+ difference spectra of the eluates obtained from an octylamino-agarose column. The partially purified P-450 preparations from two human lung microsomal samples showed high activities for the conversion of both (+)- and (-)-isomers of 7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene to genotoxic products. After DEAE-cellulose column chromatography, a partially purified P-450 fraction containing polypeptides of Mr 52,000 and 58,000 was obtained from the early fraction of the octylamino-agarose column eluate, and an electrophoretically homogeneous protein having a molecular weight of approximately 52,000 was recovered from a latter fraction. The amino-terminal amino acid sequences of the two peptides in the earlier fraction were determined; neither polypeptide appears to resemble any known P-450 protein. The protein from the latter octylamino-agarose fraction was immunoreactive with anti-rat P-450 1A2 and anti-human P-450 1A2 but not with antibodies raised against other P-450 enzymes or autoimmune antibodies that specifically recognize human P-450 1A2. A tryptic peptide was isolated from the preparation, and the amino acid sequence matched that of human P-450 1A1 perfectly (residues 31-48) but not that of human P-450 1A2. All of nine human lung microsomal samples examined contained proteins that were immunoreactive with rabbit anti-rat P-450 1A2 and catalyzed the activation of 7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene. The activities could be inhibited by rabbit anti-rat P-450 1A2 and, to a lesser extent, by anti-rat P-450 1A1. The addition of 7,8-benzoflavone caused inhibition or stimulation, depending upon the particular human lung microsomal preparation. Thus, this work clearly shows that human lung microsomes contain at least two major P-450 enzymes; human P-450 1A1 is present in lungs and can actually catalyze the activation of environmental procarcinogens, including polycyclic aromatic hydrocarbons.T Shimada, C H Yun, H Yamazaki, J C Gautier, P H Beaune, F P Guengerich