N-acetyltransferase activity in rainbow trout liver and in vitro biotransformation of chlorinated anilines and benzenes in fish.

1. N-acetyl transferase activity in liver homogenate of rainbow trout (Oncorhynchus mykiss) was studied. Enzyme activity depends on the concentration of cofactor, has a broad pH and temperature optimum, is not linear with protein concentration within the whole range tested, and does not decrease upon storage at -70 degrees C. 2. In vitro biotransformation of several chlorinated anilines and benzenes was studied in liver homogenates of rainbow trout and swordtail (Xiphophorus helleri). Several phase I and II products were detected in the simple in vitro biotransformation assays using different cofactors NADPH-regenerating system and acetyl-CoA, respectively. Acetylation of di-ortho substituted anilines was not observed. 3. Apparent Vmax and Km values for the acetylation of trichloroanilines have been determined using rainbow trout liver homogenate. The rate or extent of N-acetylation is related to the structure and properties of the chlorinated anilines. 4. Comparison of the data for the two species showed that there are no apparent qualitative differences in the in vitro fate of the chlorinated anilines and benzenes studied. It is concluded that results obtained for these chemicals in the in vitro biotransformation assay can be extrapolated between the taxonomic families of Salmonidae and Poeciliidae. 5. The in vitro and in vivo N-acetylation of the chlorinated anilines turned out to be strikingly similar. Therefore, simple in vitro systems may be of use in assessing the potential of chemicals to bioconcentrate.

[1]  A. Opperhuizen,et al.  Biotransformation of Organic Chemicals by Fish: Enzyme Activities and Reactions , 1989 .

[2]  J. Allen,et al.  Metabolism and elimination of benzocaine by rainbow trout, Oncorhynchus mykiss. , 1991, Xenobiotica; the fate of foreign compounds in biological systems.

[3]  W. Weber,et al.  Chapter 9 – Acetylation , 1980 .

[4]  W. Shiu,et al.  Factors Determining Partitioning of Hydrophobic Organic Chemicals in Aquatic Organisms , 1987 .

[5]  D. Parke.  Cytochromep-450 and the detoxication of environmental chemicals , 1981 .

[6]  T. Bergsjø.  Absorption from Water as an Alternative Method for the Administration of Sulphonamides to Rainbow Trout, Salmo Gairdneri* , 1978, Acta Veterinaria Scandinavica.

[7]  M. Wick,et al.  An isozyme-selective affinity label for rat hepatic acetyltransferases. , 1990, Biochemical pharmacology.

[8]  J. Hermens,et al.  Qualitative and quantitative modelling of toxic effects of organophosphorous compounds to fish. , 1991, The Science of the total environment.

[9]  H. Kolb,et al.  Characterization of the active site, substrate specificity and kinetic properties of acetyl-CoA:arylamine N-acetyltransferase from pigeon liver. , 1983, Biochimica et biophysica acta.

[10]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[11]  M. James.  Conjugation of organic pollutants in aquatic species. , 1987, Environmental health perspectives.

[12]  P. Boyer,et al.  Kinetic characteristics of the acetylation of isoniazid and p-aminosalicylic acid by a liver-enzyme preparation. , 1962, Biochimica et biophysica acta.

[13]  M. BradfordM.  たんぱく質‐色素結合の原理を用いるμg量のたんぱく質の定量のための迅速,高感度法 , 1976 .

[14]  B. Burchell,et al.  Glucuronidation in fish , 1991 .

[15]  R. Nagel,et al.  Bioconcentration, metabolism and toxicity of substituted anilines in the zebrafish (Brachydanio rerio). , 1991, The Science of the total environment.

[16]  J. B. Hunn,et al.  Turnover and Urinary Excretion of Free and Acetylated M.S. 222 by Rainbow Trout, Salmo gairdneri , 1968 .

[17]  S. Cohen,et al.  N-acetylation of drugs: isolation and properties of an N-acetyltransferase from rabbit liver. , 1967, Molecular pharmacology.

[18]  Barry G. Oliver,et al.  Bioconcentration factors of some halogenated organics for rainbow trout: limitations in their use for prediction of environmental residues. , 1985, Environmental science & technology.

[19]  J. Gorrod,et al.  The metabolism of aromatic amines. , 1986, Xenobiotica; the fate of foreign compounds in biological systems.

[20]  C. Klaassen,et al.  Hepatic phase I and phase II biotransformations in quail and trout: comparison to other species commonly used in toxicity testing. , 1983, Toxicology and applied pharmacology.

[21]  Joop L. M. Hermens,et al.  Influence of biotransformation on the relationship between bioconcentration factors and octanol - wa , 1992 .

[22]  J. Lech,et al.  Biotransformation and induction: implications for toxicity, bioaccumulation and monitoring of environmental xenobiotics in fish. , 1987, Environmental health perspectives.

[23]  G. Tarr,et al.  Purification, physicochemical, and kinetic properties of liver acetyl-CoA:arylamine N-acetyltransferase from rapid acetylator rabbits. , 1987, Molecular pharmacology.

[24]  J. Lech,et al.  In vitro and in vivo metabolism of 3-trifluoromethyl-4-nitrophenol (TFM) in rainbow trout. , 1972, Comparative and general pharmacology.

[25]  D. Buhler,et al.  Flavin-containing monooxygenase activity in liver microsomes from the rainbow trout (Oncorhynchus mykiss) , 1991 .

[26]  Joop L. M. Hermens,et al.  Biotransformation and toxicokinetics of trichloroanilines in fish in relation to their hydrophobicity , 1993 .

[27]  W. Weber,et al.  New spectrophotometric and radiochemical assays for acetyl-CoA: arylamine N-acetyltransferase applicable to a variety of arylamines. , 1985, Analytical biochemistry.

[28]  S. Cohen,et al.  The mechanism of isoniazid acetylation by human N-acetyltransferase. , 1968, Biochimica et biophysica acta.