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Search results for: Rabbit Anti-Human CYP1A1 Antibodies

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#17728539   2007/08/29 To Up

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

2766 related Products with: Observational study of hepatic cytochrome P-450 protein expression and activity in summer flounder (Paralichtys dentatus) after combination ormetoprim-sulfadimethoxine treatment.

1 Set1mg1 Set0.1mg1 Set100ug Lyophilized100ug Lyophilized1001 Set50 1 Set1 Set

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#15210296   // To Up

Characterization and profiling of hepatic cytochromes P450 and phase II xenobiotic-metabolizing enzymes in beluga whales (Delphinapterus leucas) from the St. Lawrence River Estuary and the Canadian Arctic.

Cytochromes P450 (CYP, phase I) and conjugating (phase II) enzymes can be induced by and influence the toxicokinetics (metabolism) and toxicity of xenobiotic contaminants in exposed organisms. Beluga whale (Delphinapterus leucas) from the endangered St. Lawrence (SL) River Estuary population exhibit deleterious health effects and various severe pathologies that have been associated with contaminant exposure. In contrast, such effects (e.g. reproductive and immunological impairment) are generally less frequent in less exposed populations in the Canadian Arctic (CA). In the present study, opportunistic sampling resulted in the collection immediately after death of liver tissue from a single female neonate SL beluga (SL6) and male and female CA beluga (n=10) from the Arviat region of western Hudson Bay, in addition to sampling of stranded carcasses of male and female SL beluga (n=5) at least 12 h postmortem. We immunologically characterized cross-reactive proteins of hepatic microsomal CYP1A, CYP2B, CYP3A, CYP2E, epoxide hydrolase (EH) and uridine diphosphoglucuronosyl transferase (UDPGT) isozymes. Cross-reactive proteins were found in all SL and CA beluga using anti-rat CYP1A1, anti-rainbow trout CYP3A, anti-human CYP2E1, anti-rabbit EH and anti-human UDPGT1A1 polyclonal antibodies (Abs), whereas faintly cross-reactive CYP2B proteins were only found in SL6 and the CA samples using an anti-rabbit CYP2B1 Ab. In corresponding catalytic activity assessments, only SL6 and all CA beluga microsomal samples exhibited CYP1A-mediated 7-ethoxyresorufin O-deethylase (EROD) activity (51-260 pmol/mg/min), CYP3A-mediated activity (113-899 pmol/mg/min) based on the formation of 6beta-hydroxytestosterone using a testosterone hydroxylase assay, and UDPGT activity (830-4956 pmol/mg/min) based on 1-naphthylglucuronide formation. The marginal cross-reactivity with the anti-CYP2B1 Ab and lack of catalytically measurable hydroxytestosterone isomers associated with CYP2B-type activity in all the SL and CA animals is suggestive of low CYP2B-type enzyme expression in beluga. The absence of measurable total P450 enzyme levels and catalytic activities in samples from the stranded SL belugas suggested catalytically inactive enzymes as a consequence of tissue degradation related due to the time delay of sample collection after death. However, all SL and CA animals demonstrated similar, immunologically cross-reactive phase I and II hepatic enzyme profiles, which is suggestive of the importance of metabolism in the toxicokinetics and fate of xenobiotics in animals from both populations
Melissa A McKinney, Augustine Arukwe, Sylvain De Guise, Daniel Martineau, Pierre Béland, André Dallaire, Stéphane Lair, Michel Lebeuf, Robert J Letcher

1608 related Products with: Characterization and profiling of hepatic cytochromes P450 and phase II xenobiotic-metabolizing enzymes in beluga whales (Delphinapterus leucas) from the St. Lawrence River Estuary and the Canadian Arctic.

10 mg 5 G2.5 mg100ug1 mg1,000 tests100ul100ug100 mg1000

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#11370663   // To Up

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

1193 related Products with: Induction of CYP1A by benzo[k]fluoranthene in human hepatocytes: CYP1A1 or CYP1A2?

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