Oxidation of barbiturates and the glucuronidation of 1-napthol in perfused rat liver and in microsomes

Kw, Bock

doi:10.1007/bf00499191

Cited by 27 publications

(5 citation statements)

References 24 publications

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“…7-Ethoxycoumarin and 7-ethoxyresorufin dealkylase (ECOD, EROD), aldrin epoxidase (ALD), aromatase, epoxide hydrolase (EH), glutathione-S-transferase (GS-T), UDP-glucuronyltransferase (GLU-T) and in vitro testosterone hydroxylation were determined using published methods (Ullrich and Weber, 1972;Burke et al, 1977;Wolff et al, 1979;Biegel et al, 1995;Guiliano et al, 1980;Habig et al, 1974;Bock, 1974;Oesch et al, 1992).…”

Section: Determination Of Liver Enzyme Activitiesmentioning

confidence: 99%

Evaluation of the rodent Hershberger bioassay: Testing of coded chemicals and supplementary molecular-biological and biochemical investigations

2007

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Section: Determination Of Liver Enzyme Activitiesmentioning

confidence: 99%

Evaluation of the rodent Hershberger bioassay: Testing of coded chemicals and supplementary molecular-biological and biochemical investigations

2007

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“…UDP-glucuronyltransferase activity was measured following the transfer of glucoronic acid from UDPglucuronic acid to 1-naphthol using a modification of the method described by Bock (1974). 1-Naphthol was removed by back-extraction with chloroform and fluorescence of naphthol glucuronide was measured in a Hitachi spectrofluorometer F-3000 used at 290 and 330 nm excitation and emission wavelengths.…”

Section: Enzyme Assaysmentioning

confidence: 99%

Embryonic turkey liver: activities of biotransformation enzymes and activation of DNA-reactive carcinogens

et al. 2004

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Avian embryos are a potential alternative model for chemical toxicity and carcinogenicity research. Because the toxic and carcinogenic effects of some chemicals depend on bioactivation, activities of biotransformation enzymes and formation of DNA adducts in embryonic turkey liver were examined. Biochemical analyses of 22-day in ovo turkey liver post-mitochondrial fractions revealed activities of the biotransformation enzymes 7-ethoxycoumarin de-ethylase (ECOD), 7-ethoxyresorufin de-ethylase (EROD), aldrin epoxidase (ALD), epoxide hydrolase (EH), glutathione S-transferase (GST), and UDP-glucuronyltransferase (GLUT). Following the administration of phenobarbital (24 mg/egg) on day 21, enzyme activities of ECOD, EROD, ALD, EH and GLUT, but not of GST, were increased by two-fold or higher levels by day 22. In contrast, acute administration of 3-methylcholanthrene (5 mg/egg) induced only ECOD and EROD activities. Bioactivation of structurally diverse pro-carcinogens was also examined using (32)P-postlabeling for DNA adducts. In ovo exposure of turkey embryos on day 20 of gestation to 2-acetylaminofluorene (AAF), 4,4'-methylenebis(2-chloroaniline) (MOCA), benzo[a]pyrene (BaP), and 2-amino-3,8-dimethylimidazo[4,5- f]quinoxaline (MeIQx) resulted in the formation of DNA adducts in livers collected by day 21. Some of the DNA adducts had (32)P-postlabeling chromatographic migration patterns similar to DNA adducts found in livers from Fischer F344 rats exposed to the same pro-carcinogens. We conclude that 21-day embryonic turkey liver is capable of chemical biotransformation and activation of genotoxic carcinogens to form DNA adducts. Thus, turkey embryos could be utilized to investigate potential chemical toxicity and carcinogenicity.

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“…Enzyme luminescence immunometric tests were used to determine T3, T4 and TSH. 7-Ethoxycoumarin O-deethylase (ECOD), 7-ethoxyresorufin Odealkylase (EROD), aldrin epoxidase (ALD), epoxide hydrolase (EH), glutathione-S-transferase (GS-T) and UDP-glucuronyltransferase (GLU-T) activities, and in vitro testosterone hydroxylation were determined in liver tissue samples of study A using published methods (Ullrich and Weber 1972;Burke et al 1977;Wolff et al 1979;Giuliano et al 1980;Habig et al 1974;Bock 1974;Oesch et al 1992). …”

Section: Clinical Pathologymentioning

confidence: 99%

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Andrews

Freyberger

Hartmann

et al. 2002

Archives of Toxicology

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Groups of five male and female Wistar rats were treated by gavage with 0, 0.01, 0.05 or 0.2 mg/kg body weight of the known synthetic estrogen ethinylestradiol for 28-32 days according to a modified enhanced OECD Test Guideline no. 407 in order to investigate which of the current and/or additional parameters would detect effects on the endocrine system reliably and sensitively and to provide data on intra-laboratory variability. Two identical studies (A and B) were run concurrently. The modified enhanced protocol requests the additional determination of triiodothyronine, thyroxine and thyroid-stimulating hormone (TSH), of the stage of the estrous cycle to ensure necropsy of all females in diestrus, of the number and morphology of cauda epididymal spermatozoa, and of additional organ weights (ovaries, uterus, thyroid, and male accessory reproductive organs), and histopathology of additional organs (pituitary, epididymides, coagulation glands, pancreas, and vagina). There were no treatment-related mortalities, clinical signs or changes in behavioral parameters. In male rats, 0.2 mg/kg was the maximum tolerated dose (MTD) resulting in reduced body weight gain. The only treatment-related alteration in hematological parameter was prolonged blood clotting time in high-dose females of both studies. Changes in clinical chemistry observed in study A were elevated alkaline phosphatase activity (high-dose females) and triglyceride levels (mid- and high-dose females and high-dose males). Changes in thyroid hormones and TSH of treated animals showed high variability with no clear dose-dependency, and could not be clearly related to estrogenic activity. In accordance to a suppression of the hypothalamic-pituitary-gonadal axis, decreased relative organ weights of the male accessory reproductive organs were obtained in both studies at the high dose. Corresponding histological changes were degeneration of the testicular germinal epithelium and atrophy of Leydig cells and of all accessory sex glands. Atrophy of the coagulating gland (study A) and seminal vesicles (study B) was also seen at 0.05 mg/kg. A marked increase in relative adrenal weight in male rats, accompanied by decreased vacuolization of zona fasciculata cells observed in both studies at the high dose seems to reflect an activation of the hypothalamic-pituitary-adrenal axis. The male mammary gland was sensitively affected. Increased numbers of small basophilic over large acidophilic cells indicated an estrogen-mediated feminisation and were detected at the low (study A) or mid dose (study B). Co-mitogenic properties of estrogens in rat liver were reflected by increased relative liver weights in females at the mid and high dose of study A and also at the high dose in study B. No treatment-related changes in endocrine organ weights were observed in treated females. Histological changes in the ovaries were increased numbers of apoptotic corpora lutea (from mid dose, study B) and of early stage follicles at the high dose in both studies. Classical direct estrogenic effects...

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Oxidation of barbiturates and the glucuronidation of 1-napthol in perfused rat liver and in microsomes

Cited by 27 publications

References 24 publications

Evaluation of the rodent Hershberger bioassay: Testing of coded chemicals and supplementary molecular-biological and biochemical investigations

Evaluation of the rodent Hershberger bioassay: Testing of coded chemicals and supplementary molecular-biological and biochemical investigations

Embryonic turkey liver: activities of biotransformation enzymes and activation of DNA-reactive carcinogens

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