Mercapturic acids

Commandeur JNM, Vermeulen NPE. 1990a. Identification of N-acetyl-S-(2,2-dichlorovinyl) and N-acetyl-S-(l,2-dichlorovinyl)-L-cysteine as two regioisomeric mercapturic acids of trichloroethylene in the rat. Chem Res Toxicol 3 212-218. 

Commandeur JN, Boogaard PJ, Mulder GJ, et al. 1991. Mutagenicity and cytotoxicity of two regioisomeric mercapturic acids and cysteine S-conjugates of trichloroethylene. Arch Toxicol 65 373-380. 

Goeptar, AR, Commandeur JNM, Vanommen B, et al. 1995. Metabolism and kinetics of trichloroethylene in relation to toxicity and carcinogenicity. Relevance of the mercapturic acid pathway. Chem. Res. Toxicol. 8 3-21. 

Vamvakas S, Dekant W, Berthold K, et al. 1987. Enzymatic transformation of mercapturic acids derived from halogenated alkenes to reactive and mutagenic intermediates. Biochem Pharmacol 36 2741-3748. 

Atrazine, used as a selective pre- and post-emergence herbicide to control annual weeds in several crops, is the most representative compound of this group. It is also used as a non-selective herbicide in non-crop areas. After absorption, the compound is metabolized to dealkylated and deisopropy-lated derivatives. The unchanged compound and its metabolites are excreted in urine, where they can be detected by chromatography or enzyme-linked immunosorbent assay (Lucas et al., 1993). A mercapturic acid conjugate of atrazine has also been found in urine samples of workers spraying this herbicide (Lucas et al., 1993) (Table 6). 

Biomarkers of Exposure and Effect. The presence of thiocyanate and 2-cyanoethyl mercapturic acid have been monitored in urine as indicators of acrylonitrile exposure. 

Tardif R, Talbot D, Gerin M, et al. 1987. Urinary excretion of mercapturic acids and thiocyanate in rats exposed to acrylonitrile Influence of dose and route of administration. Toxicol Lett 39 255-261. 

Van Bladeren PJ, Delbressine LP, Hoogeterp J J, et al. 1981. Formation of mercapturic acids from acrylonitrile, crotononitrile, and cinnamonitrile by direct conjugation and via an intermediate oxidation process. Drug Metab Dispos 9 246-249. 

Cysteine conjugation Mercapturic acid (from GSH conjugation) r-ch=ch2> R-CH2-CH2-Cys +121 (119) +161... 

FIGURE 7.18 Reaction scheme by which glutathione conjugates are converted to mercapturic acid conjugates. 

Roubal et al. (8) applied TLC to the separation and identification of metabolites of l c-iabeled naphthalene administered to coho salmon fingerlings via intraperitoneal injection. 1-Naphthol, a dihydrodiol, mercapturic acid, 1-naphthyl glucuronic acid and a glycoside/sulfate fraction were identified in brain, liver, gall bladder, and muscle 1-naphthol, a dihydrodiol, and 1-naphthyl glucuronic acid were the only metabolites found in heart. 

Co., Richmond, Calif. Hexamethyleneimine (HMI) was purchased from Matheson Coleman Bell Co. S (Hexahydro-[2-I tC]azepine-l-car-bonyl)-N-acetyl-L-cysteine (molinate mercapturic acid) was provided by DeBaun et al. (12). Caprolactam was purchased from J.T,... 

T. Huwer, H. J. Altmann, W. Grunow, S. Lenhardt, M. Przybylski, G. Eisenbrand, Coumarin Mercapturic Acid Isolated from Rat Urine Indicates Metabolic Formation of Coumarin 3,4-Epoxide , Chem. Res. Toxicol. 1991, 4, 586-590. 

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