Effect of the fungicide clotrimazole on the bioconcentration of benzo[a]pyrene in gizzard shad (Dorosoma cepedianum): In vivo and in vitro inhibition of cytochrome P4501A activity

Clotrimazole was found to inhibit in vivo and in vitro hepatic microsomal ethoxyresorufin O‐deethylase (EROD) activity in gizzard shad (Dorosoma cepedianum). Gizzard shad pretreated with 50 mg clotrimazole/kg and then exposed for 1 or 3 d to benzo[a]pyrene (BaP) (0.86 μg/L) had significantly lower EROD activity compared to fish that were exposed to BaP alone. Following 1 and 3 d of BaP exposure, groups pretreated with clotrimazole had a 14‐ and 4‐fold decrease in EROD activity and had biocon‐centrated 8 and 11 times more parent BaP, respectively, compared to groups exposed to BaP alone. Addition of clotrimazole to BaP‐induced microsomes produced a type II binding spectrum and was an effective in vitro inhibitor of EROD activity. The median inhibitory concentration for EROD activity was 0.51 μM clotrimazole. Kinetic and spectral experiments suggest that the mechanism of inhibition by clotrimazole is noncompetitive. Reduction in the rate of oxidative BaP metabolism is hypothesized to result from noncompetitive inhibition of cytochrome P4501A and other P450 enzymes that metabolize BaP.

[1]  D. Feldman,et al.  Ketoconazole blocks adrenal steroidogenesis by inhibiting cytochrome P450-dependent enzymes. , 1983, The Journal of clinical investigation.

[2]  J. Ritter,et al.  Induction and inhibition of rat hepatic drug metabolism by N-substituted imidazole drugs. , 1987, Drug metabolism and disposition: the biological fate of chemicals.

[3]  G. Monod,et al.  Inhibition of ovarian microsomal aromatase and follicular oestradiol secretion by imidazole fungicides in Rainbow trout , 1993 .

[4]  F. J. Oppenoorth,et al.  Glutathione-dependent degradation of parathion and its significance for resistance in the housefly , 1972 .

[5]  J. Mason,et al.  Ketoconazole: a potent inhibitor of cytochrome P-450-dependent drug metabolism in rat liver. , 1984, Drug metabolism and disposition: the biological fate of chemicals.

[6]  G. Tsokos,et al.  Monoclonal antibody-directed radioimmunoassay detects cytochrome P-450 in human placenta and lymphocytes. , 1985, Science.

[7]  J. Oris,et al.  Comparison of P-4501A1 monooxygenase induction in gizzard shad (Dorosoma cepedianum) following intraperitoneal injection or continuous waterborne-exposure with benzo[a]pyrene: Temporal and dose-dependent studies , 1994 .

[8]  Y. Cheng,et al.  Relationship between the inhibition constant (K1) and the concentration of inhibitor which causes 50 per cent inhibition (I50) of an enzymatic reaction. , 1973, Biochemical pharmacology.

[9]  R. Kahl,et al.  Clotrimazole as an inhibitor of benzo[a]pyrene metabolite-DNA adduct formation in vitro and of microsomal mono-oxygenase activity. , 1980, Drug metabolism and disposition: the biological fate of chemicals.

[10]  J. Bach,et al.  Effects of the fungicide prochloraz on xenobiotic metabolism in rainbow trout: in vivo induction. , 1989, Xenobiotica; the fate of foreign compounds in biological systems.

[11]  R. Tarone,et al.  Monoclonal antibody phenotyping of interindividual differences in cytochrome P-450-dependent reactions of single and twin human placenta. , 1984, Cancer research.

[12]  J. Oris,et al.  Influence of environmental factors on the physiological condition and hepatic ethoxyresorufin o‐deethylase (erod) activity of gizzard shad (Dorosoma cepedianum) , 1995 .

[13]  H. van den Bossche,et al.  Biochemical effects of miconazole on fungi. II. Inhibition of ergosterol biosynthesis in Candida albicans. , 1978, Chemico-biological interactions.

[14]  C. F. Wilkinson,et al.  Imidazole derivatives--a new class of microsomal enzyme inhibitors. , 1972, Biochemical pharmacology.

[15]  G. Bennett.  Illustrated handbook of physical chemical properties and environmental fate of organic chemicals, vol. III, volatile organic chemicals: by D. MacKay, W.Y. Shiu and K.C. Ma, Lewis Publishers, Boca Raton, FL, 1993, 916 pages, price US$ 95.00, ISBN 0-87371-973-5 , 1994 .

[16]  I. H. Segel.  Enzyme Kinetics: Behavior and Analysis of Rapid Equilibrium and Steady-State Enzyme Systems , 1975 .

[17]  A. Cherniack,et al.  Clotrimazole, an inhibitor of epidermal benzo(a)pyrene metabolism and DNA binding and carcinogenicity of the hydrocarbon. , 1984, Cancer research.

[18]  A. D. Rodrigues,et al.  Adverse reactions of imidazole antifungal agents: computer graphic studies of cytochrome P-450 interactions. , 1989, Journal of biochemical toxicology.

[19]  C. F. Wilkinson,et al.  Structure-activity relationships in the effects of 1-alkylimidazoles on microsomal oxidation in vitro and in vivo. , 1974, Biochemical pharmacology.

[20]  J. Mason,et al.  Imidazole antimycotics: inhibitors of steroid aromatase. , 1985, Biochemical pharmacology.

[21]  D. Rodbard,et al.  Simultaneous analysis of families of sigmoidal curves: application to bioassay, radioligand assay, and physiological dose-response curves. , 1978, The American journal of physiology.

[22]  R. Mayer,et al.  Ethoxyresorufin: direct fluorimetric assay of a microsomal O-dealkylation which is preferentially inducible by 3-methylcholanthrene. , 1974, Drug metabolism and disposition: the biological fate of chemicals.

[23]  A. D. Rodrigues,et al.  Spectral and kinetic studies of the interaction of imidazole anti-fungal agents with microsomal cytochromes P-450. , 1987, Xenobiotica; the fate of foreign compounds in biological systems.

[24]  K. Speeg,et al.  The effect of ketoconazole on hepatic oxidative drug metabolism in the rat in vivo and in vitro. , 1985, Drug metabolism and disposition: the biological fate of chemicals.

[25]  J. Bach,et al.  Effects of the fungicide prochloraz on xenobiotic metabolism in rainbow trout: inhibition in vitro and time course of induction in vivo. , 1989, Xenobiotica; the fate of foreign compounds in biological systems.

[26]  R. Estabrook,et al.  Inhibition of rat liver microsomal cytochrome P-450 steroid hydroxylase reactions by imidazole antimycotic agents. , 1986, Biochemical pharmacology.

[27]  S. Sikka,et al.  In vitro inhibition of testosterone biosynthesis by ketoconazole. , 1985, Endocrinology.

[28]  Gary M. Rand,et al.  Fundamentals of Aquatic Toxicology , 1985 .

[29]  R. Metcalf,et al.  The environmental fate of three carcinogens: Benzo-(α)-pyrene, benzidine, and vinyl chloride evaluated in laboratory model ecosystems , 1977, Archives of environmental contamination and toxicology.

[30]  M. Henry,et al.  Effects of sterol biosynthesis-inhibiting (SBI) fungicides on cytochrome P-450 oxygenations in fungi , 1984 .

[31]  F. Guengerich,et al.  Monoclonal antibodies that inhibit enzyme activity of 3-methylcholanthrene-induced cytochrome P-450. , 1982, Cancer research.

[32]  B. Jiminez,et al.  Detoxification enzymes as indicator of environmental stress on fishes. , 1990 .