Polychlorinated biphenyls metabolism

Bedard DL, ML Haberl, RJ May, MJ Brennan (1987) Evidence for novel mechanisms of polychlorinated biphenyl metabolism in Alcaligenes eutrophus H %50. Appl Environ Microbiol 53 1103-1112. 

S. Safe and O. Hutzinger, Polychlorinated Biphenyls Photolysis of 2,4,6,2, 6 Hexachlorobiphenyl, Nature232 (1971) 641-42 O. Hutzinger et al., Polychlorinated Biphenyls Metabolic Behavior of Pure Isomers in Pigeons, Rats, and Brook Trout, Science 178 (1972) 512-14 O. Hutzinger et al., Identification of Metabolic Dechlorination of Highly Chlorinated Biphenyl in Rabbits, Nature 252 (1974) 698-99. 

Focht, D. D. Brunner, W. (1985). Kinetics of biphenyl and polychlorinated biphenyl metabolism in soil. Applied and Environmental Microbiology, 50, 1058-63. 

Hutzinger, O. Nash, D.M. Safe, S. DeFreitas, A.S.W. Norstrom, R.J. Wildish, D.J. Zitko, V, Polychlorinated biphenyls Metabolic behavior of pure isomers in pigeons, rats, and brook trout Science 1978, 178, 312-314. 

Borlakogln, J.T., Wilkins, J.P.G., and Walker, C.H. (1988). Polychlorinated biphenyls in sea birds—molecnlar features and metabolic interpretations. Marine Environmental Research 24, 15-19. 

Furukawa K, N Tomizuka, A Kamibayashi (1979) Effect of chlorine substitution on the bacterial metabolism of various polychlorinated biphenyls. Appl Environ Microbiol 38 301-310. 

Table I. Optical Purity of the Dihydrodiol Metabolites Formed in the Metabolism of Benzo[a]pyrene by Liver Microsomes from Untreated, Phenobarbital (PB)-, 3-Methylcholanthrene (3MC)-, and Polychlorinated Biphenyls (PCBs, Aroclor 1254)-Treated Rats...

Borlakoglu, J.T., J.P.G. Wilkins, C.H. Walker, and R.R. Dils. 1990. Polychlorinated biphenyls (PCBs) in fisheating seabirds. III. Molecular features and metabolic interpretations of PCB isomers and congeners in adipose tissues. Comp. Biochem. Physiol. 97C 173-177. 

Elskus, A.A., J J. Stegeman, J.W. Gooch, D.E. Black, and R.J. Pruell. 1994. Polychlorinated biphenyl congener distributions in winter flounder as related to gender, spawning site, and congener metabolism. Environ. Sci. Technol. 28 401-407. 

Sipes, I.G. and R.G. Schnellmann. 1987. Biotransformation of PCBs metabolic pathways and mechanisms. Pages 97-110 in S. Safe (ed.). Polychlorinated Biphenyls (PCBs) Mammalian and Environmental Toxicology. Environ. Toxin Ser. 1. Springer-Verlag, New York. 

Highly halogenated organic compounds such as polychlorinated biphenyls and perchloroethylene appear to be too highly oxidised and low in energy content to serve as sources of electrons and energy for microbial metabolism. Bacteria are more likely to use them as electron acceptors in cell-membrane-based respiration processes [154]. The environmental fate of halogenated polymers such as polyvinylchloride or Teflon may depend on the question of whether it will be appropriate to sustain de-halorespiration processes. 

The formation of polar metabolites from nonpolar materials may actually facilitate monitoring programs—in many cases the polar chemicals are highly concentrated in certain body fluids such as bile and urine. On the other hand, materials such as certain cyclodienes and polychlorinated biphenyls, which are very lipid soluble and resistant to metabolism, may accumulate and these chemicals may persist in the environment and may be transferred via the food chain to man. There is also interest in these biotransformation processes in lower organisms since the simplicity of these systems may lead to a better understanding of the phylogenetic development of xenobiotic metabolism. 

Polychlorinated biphenyls (PCBs) have been used in various industrial processes during the past 40 years but were not recognized as major environmental contaminants until 1966 (1). Fish as a major food source have attained the dubious honor of being the most frequently cited PCB contamination problem (2). In the following presentation disposition of PCBs in fish will be discussed from four points of view accumulation, metabolism, distribution and elimination. No attempt will be made to cover PCB residue levels found in fish in nature (3) or acute or chronic toxicity of PCBs in fish (4-20). 

Lidman, U., F8rlin, L., Molander, 0. and Axelson, G. Induction of the drug metabolizing system in rainbow trout (Salmo gairdnerii) liver by polychlorinated biphenyls (PCBs). Acta Pharmacol, et Toxicol. (1976) 39., 262-272. 

Kaiser, K.L. and Wong, P.T.S. Bacterial degradation of polychlorinated biphenyls. 1. Identification of some metabolic products fromAroclor 1242, Bull. Environ. Contam. Toxicol, ll(3) 291-296, 1974. 

Acquevella JF et al Assessment of clinical, metabolic, dietary, and occupational correlations with serum polychlorinated biphenyl levels among employees at an electric capacitor manufacturing plant. J Occup Med 28 1177-1180, 1986... 

Boon, J.R and Duinker, J.C. (1985). Kinetics of polychlorinated biphenyl (PCB) components in juvenile sole Solea solea) in relation to concentrations in water and to hpid metabolism under conditions of starvation. Aquatic Toxicology, 7 119-134. 

Environmental chemicals and pollutants are also capable of inducing P450 enzymes. As previously noted, exposure to benzo[a]pyrene and other polycyclic aromatic hydrocarbons, which are present in tobacco smoke, charcoal-broiled meat, and other organic pyrolysis products, is known to induce CYP1A enzymes and to alter the rates of drug metabolism. Other environmental chemicals known to induce specific P450s include the polychlorinated biphenyls (PCBs), which were once used widely in industry as insulating materials and plasticizers, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin, TCDD), a trace byproduct of the chemical synthesis of the defoliant 2,4,5-T (see Chapter 56). 

The polychlorinated biphenyls (PCBs, coplanar biphenyls) have been used in a large variety of applications as dielectric and heat transfer fluids, lubricating oils, plasticizers, wax extenders, and flame retardants. Their industrial use and manufacture in the USA were terminated by 1977. Unfortunately, PCBs persist in the environment. The products used commercially were actually mixtures of PCB isomers and homologs containing 12-68% chlorine. These chemicals are highly stable and highly lipophilic, poorly metabolized, and very resistant to environmental degradation they bioaccumulate in food chains. Food is the major source of PCB residues in humans. 

Borlakoglu JT, Wilkins JP. 1993. Metabolism of di-, tri- and tetrabromobiphenyls by hepatic microsomes isolated from control animals and animals treated with Aroclor 1254, a commercial mixture of polychlorinated biphenyls (PCBs). Comp Biochem Physiol C 105(1) 107-112. 

Byme JJ, Carbone JP, Hanson EA. 1987. Hypothyroidism and abnormalities in the kinetics of thyroid hormone metabolism in rats treated chronically with polychlorinated biphenyl and polybrominated biphenyl. Endocrinology 21 520-527. 

LameshRA. 1992. Polychlorinated biphenyls An overview of metabolic toxicologic and health consequences. Vet Hum Toxicol 34 256-260. 

Furukawa, K. Matsumura, F. (1976). Microbial metabolism of polychlorinated biphenyls Studies on the relative degradability of polychlorinated biphenyl components by Alkaligenes sp. Journal of Agricultural and Food Chemistry, 24, 251-6. 

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