Isozyme-specific monoclonal antibody-directed assessment of induction of hepatic cytochrome p-450 by clotrimazole.
Clotrimazole, an N-substituted imidazole widely used as an antifungal agent, has been shown to both inhibit and induce hepatic cytochrome P-450 and related monooxygenase activities. In this study the profile of hepatic cytochrome P-450 isozyme(s) induced by clotrimazole treatment of male Sprague-Dawley rats was investigated. Clotrimazole administration (100 mg/kg, daily for 4 days, ig) resulted in 86% induction of spectrally detectable cytochrome P-450 in hepatic microsomes. In these microsomes 7-ethoxycoumarin O-deethylase (126%), aminopyrine N-demethylase (176%), benzphetamine N-demethylase (117%), p-nitrophenol hydroxylase (89%), and 7-ethoxyresorufin O-deethylase (62%) activities were significantly induced, whereas aryl hydrocarbon hydroxylase activity remained unchanged. Characterization of cytochrome P-450 isozyme(s) in hepatic microsomes prepared from clotrimazole-treated animals was based on the immunoreactivity of these microsomes with highly specific monoclonal antibodies (MAbs) raised against 3-methylcholanthrene-specific P-450 (MAb 1-7-1), phenobarbital-specific P-450 (MAb 2-66-3), pregnenolone-16 alpha-carbonitrile-specific P-450 (MAb C2), and ethanol-inducible P-450 (MAb 1-98-1). Western blot analysis of hepatic microsomes prepared from clotrimazole-treated animals with MAb 2-66-3, MAb 1-98-1, and MAb C2 revealed strong immunoreactive bands, whereas moderate reactivity was observed with MAb 1-7-1. MAb 2-66-3 significantly inhibited 7-ethoxycoumarin O-deethylase activity 45%), whereas MAb 1-7-1 moderately inhibited 7-ethoxyresorufin O-deethylase activity (-30%) in clotrimazole-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)
Khan
W A
WA
Department of Dermatology, Case Western Reserve University, Cleveland, OH.
Kuhn
C
C
Merk
H F
HF
Park
S S
SS
Gelboin
H V
HV
Bickers
D R
DR
Mukhtar
H
H
D000818:Animals; D000911:Antibodies, Monoclonal; D003022:Clotrimazole / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000276:immunology; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D010634:Phenobarbital / Q000494:pharmacology; D010641:Phenotype; D011285:Pregnenolone Carbonitrile / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012967:Sodium Dodecyl Sulfate
D000911:Antibodies, Monoclonal; D007093:Imidazoles; D007527:Isoenzymes; D011285:Pregnenolone Carbonitrile; D012967:Sodium Dodecyl Sulfate; D003577:Cytochrome P-450 Enzyme System; D003022:Clotrimazole; D010634:Phenobarbital