'While performing its functions in olfaction, modification of inspired air, and protection of the lower respiratory tract from high concentrations of potentially harmful inhalants, the nasal mucosa can be injured by a number of inhalants. In this study, F344/N male rats were exposed to filtered air or hyperoxia (85 or ... More
A continuous fluorometric assay for cytochrome P-450-dependent mixed function oxidases using 3-cyano-7-ethoxycoumarin.
AuthorsWhite IN
JournalAnal Biochem
PubMed ID3189781
'A direct fluorometric procedure for the continuous determination of cytochrome P-450-dependent mixed function oxidases, using 3-cyano-7-ethoxycoumarin substrate, is described. The reaction product, 3-cyano-7-hydroxycoumarin, is fluorescent at neutral pH values (excitation and emission wavelength maxima: 408 and 450 nm, respectively). Using hepatic microsomal preparations from control rats, the enzyme(s) had an ... More
Further characterization of the expression in liver and catalytic activity of CYP2B6.
AuthorsEkins S, Vandenbranden M, Ring BJ, Gillespie JS, Yang TJ, Gelboin HV, Wrighton SA
JournalJ Pharmacol Exp Ther
PubMed ID9732386
'Previous studies in this laboratory have determined the lack of specificity of several antibody and substrate probes of CYP2B6. The goals of the current study were to examine the expression of CYP2B6 in a bank of human liver microsome (HLM) samples using a new specific monoclonal antibody (MAb 49-10-20) and ... More
Fluorescence-based assays for screening nine cytochrome P450 (P450) activities in intact cells expressing individual human P450 enzymes.
AuthorsDonato MT, Jiménez N, Castell JV, Gómez-Lechón MJ
JournalDrug Metab Dispos
PubMed ID15205384
'In this study we describe a battery of fluorescence assays for rapid measurement in intact cells of the activity of nine cytochromes P450 (P450s) involved in drug metabolism. The assays are based on the direct incubation of monolayers of cells expressing individual P450 enzymes with a fluorogenic substrate followed by ... More
Effects of cytochrome P450 inhibitors on the biotransformation of fluorogenic substrates by adult male rat liver microsomes and cDNA-expressed rat cytochrome P450 isoforms.
AuthorsMakaji E, Trambitas CS, Shen P, Holloway AC, Crankshaw DJ,
JournalToxicol Sci
PubMed ID19858067
We have evaluated the use of a panel of six fluorogenic cytochrome P450 (CYP) substrates as a potential tool for rapid screening for global changes in CYP activity in rats under different physiological conditions. The biotransformation of 3-[2-(N,N-diethyl-N-methylammonium)ethyl]-7-methoxy-4-methylcoumarin (AMMC), 7-benzyloxy-4-(trifluoromethyl)-coumarin, 7-benzyloxyquinoline, 3-cyano-7-ethoxycoumarin, 7-methoxy-4-(trifluoromethyl)-coumarin, and 7-ethoxy-4-trifluoromethyl-coumarin by microsomes from adult male ... More
Characteristics of rat hepatocytes sorted by fluorescence-activated flow cytometry. Effects of mixed function oxidase inducers.
AuthorsWhite IN, Legg RF, Manson MM, Wolf CR
JournalBiochem Pharmacol
PubMed ID2730677
Fluorescence-activated flow cytometry has been used to separate rat liver parenchymal cells into five equal computer-generated regions on the basis of their mixed function activities towards diethoxyfluorescein. Enzymic activities in the sorted fractions showed 2.3-2.9-fold enrichment of 3-cyano-7-ethoxycoumarin O-deethylase, lactate dehydrogenase and pyruvate kinase activities in the cells of region ... More
Fluorescence-activated sorting of rat hepatocytes based on their mixed function oxidase activities towards diethoxyfluorescein.
AuthorsWhite IN, Green ML, Legg RF
JournalBiochem J
PubMed ID3689348
The formation of ethoxyfluorescein and fluorescein from diethoxyfluorescein by isolated rat hepatocytes has been used as a basis for separating such cells dependent on their mixed function oxidase activities by fluorescence-activated flow cytometry. Five equal fractions defined by computer-generated regions were isolated. Non-viable cells with low fluorescence (region 1) represented ... More
Rapid determination of enzyme activities of recombinant human cytochromes P450, human liver microsomes and hepatocytes.
AuthorsGhosal A, Hapangama N, Yuan Y, Lu X, Horne D, Patrick JE, Zbaida S
JournalBiopharm Drug Dispos
PubMed ID14689466
Cytochrome P450 (CYP) substrates that yield fluorescent metabolites were used for rapid screening of drug metabolism activities of 13 recombinant human cytochromes P450, human liver microsomes and human hepatocytes. Reproducible results were obtained using a fluorescent plate reader (CytoFluor) more expediently than those generated using conventional HPLC methods. Typically, results ... More
Characterization of Clara and type II cells isolated from rat lung by fluorescence-activated flow cytometry.
AuthorsMartin J, Dinsdale D, White IN
JournalBiochem J
PubMed ID7692844
A novel procedure for the isolation of Clara cells from rat lung is described. Single-cell suspensions from male F344/TOX rat lungs, prepared by subtilisin digestion, were treated with monochlorobimane (10 microM) and anlaysed by fluorescence-activated flow cytometry. A sub-population of about 2.8% of the total, showing the highest blue fluorescence ... More