Metabolism of pentachlorophenol in vivo and in vitro

Abstract

Pentachlorophenol has earlier been shown to be metabolized in mammals to tetrachloro-p-hydroquinone. The metabolite possesses pronounced inhibitory activity on bacterial beta-glucuronidase but not on beta-glucuronidase from liver. Indirect evidence for the occurrence of both pentachlorophenol and tetrachloro-p-hydroquinone as conjugates with glucuronic acid in the urine from pentachlorophenol-treated rats is now presented. Bovine liver beta-glucuronidase has been utlizied to split the conjugates present. The in vivo metabolism of pentachlorophenol has also been studied in rats treated with phenobarbital and beta-diethylaminoethylidiphenyl propylacetate (SKF 525-A). In vitro metabolism has been studied using liver microsomes from rats pretreated with pehnobarbital. Quantitative analysis of the compounds occurring in extracts of urine or extracts from the microsomal incubates was performed by means of mass fragmentography. Pretreatment with phenobarbital increased the metabolism of pentachlorophenol to tetrachloro-p-hydroquinone both in vivo and in vitro. SKF 525-A, however, inhibited the metabolism in vitro but enhanced the metabolism in vivo when given less frequently than every 6th h. Dechlorination of pentachlorophenol is mediated by microsomal enzymes that can be induced by phenobarbital. SKF 525-A does not inhibit the dechlorination in vivo but does so in vitro.

Interactions of halogenated industrial chemicals with transthyretin and effects on thyroid hormone levels in vivo

“…Furthermore, chronic HCB treatment of experimental animals has been shown to result in significant reductions in plasma thyroid hormone levels (Rotman et al 1986). Experiments are currently in progress to determine the respective contributions of HCB and its metabolites pentachlorophenol and tetrachlorohydroquinone (Ahlborg et al 1978;Van Ommen et al 1986) in lowering thyroid hormone levels in vivo. A few DDT-like chemicals such as p,p'-DDD, o,p'-DDD and dicofol, in particular, were found to interact with thyroid hormone carrier (group 5, compounds 11/12).…”

Influence of Ph on Adsorption Kinetics of Monochlorophenols From Aqueous Solutions on Granular Activated Carbon / Wpływ Ph Na Kinetykę Adsorpcji Monochlorofenoli Z Roztworów Wodnych Na Granulowanym Węglu Aktywnym

“…They are used in a number of industries as wood, fibers, paints and leather preservatives and for the manufacturing of resins and pesticides. As a result, chlorophenols are found commonly in air, soil, wastewater, surface and ground waters [1], and in drinking water because they may be generated as by-products in the disinfection of water [2]. Because most of them are highly toxic and might produce disagreeable taste and odor to drinking water at concentrations below 0.01 mg mg/dm 3 [3,4] chlorophenols are classified as priority pollutants by the European Union [5] and US Environmental Protection Agency [6].…”

Characterization of TCHQ-induced genotoxicity and mutagenesis using the pSP189 shuttle vector in mammalian cells

“…In these individuals, PCP was detected ubiquitously in both bodily fluids (e.g., urine, serum, milk) and in tissues. Additionally, previous studies demonstrated that PCP is metabolized to tetrachlorohydroquinone (TCHQ) by rodents in vivo [2,4] and by liver enzymes from rats and humans in vitro [4,5]. Although PCP has not shown reactivity towards DNA, both PCP and TCHQ were shown to be tumor promoters in previous studies using a mouse skin model in CD-1 mice [3,6].…”