RESUMEN
Monoclonal antibody (MAb) 1-7-1 against 3-methylcholanthrene (MC)-induced forms of cytochrome P-450 (CYP) was used to characterize benzo[a]pyrene (B[a]P) metabolism in rat liver and extrahepatic tissues and its modulation by phenolic antioxidants, propyl and octyl gallates. Male Wistar rats were treated with these food additives (50 mg/kg body wt i.p.) twice weekly for 14 days alone or in combination with MC. Immunochemical inhibition of aryl hydrocarbon hydroxylase (AHH) and [14C]B[a]P metabolism (analyzed by high-performance liquid chromatography) were measured in liver, kidney, and lung microsomes. Organ-specific changes in levels of MAb-mediated inhibition of microsomal metabolism of B[a]P were observed. In liver microsomes from untreated rats, AHH was not affected by MAb, but in kidney and lung, there was 70% and 50% inhibition, respectively. In MC-treated rats, MAb reduced AHH activity by 43% in liver. Kidney and lung AHH was inhibited up to 80% by this MAb. Formation of B[a]P metabolites in MC-induced microsomes from liver and kidney was affected by MAb in a similar way. In lung, the total metabolism was inhibited by 50% by MAb treatment, but significant differences in inhibition of individual metabolites were observed. Treatment with propyl or octyl gallate alone had no effect on MAb inhibition of AHH activity in liver and lung but decreased the level of inhibition in kidney. Combined treatment with MC and propyl or octyl gallate slightly reduced the effect of MAb on AHH activity in liver and significantly reduced the level of inhibition in kidney but did not affect AHH activity in lung. The same treatment regimen dramatically reduced MAb inhibition of B[a]P metabolism in kidney but had no effect on B[a]P metabolite formation in liver. Inhibition by MAb of renal 3-hydroxy-B[a]P, 7,8-B[a]P-dihydrodiol, and 1,6-quinone-B[a]P was the most affected. In lung, treatment with gallates affected only formation of 7,8-B[a]P-dihydrodiol. These results suggest that treatment with gallates affects the CYP 1A and may change the CYP isozyme composition and, thus, alter the tissues' susceptibility to tumor induction by B[a]P.
Asunto(s)
Benzo(a)pireno/metabolismo , Ácido Gálico/análogos & derivados , Ácido Gálico/farmacología , Microsomas Hepáticos/metabolismo , Microsomas/metabolismo , Galato de Propilo/farmacología , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/farmacología , Hidrocarburo de Aril Hidroxilasas/antagonistas & inhibidores , Hidrocarburo de Aril Hidroxilasas/metabolismo , Cromatografía Líquida de Alta Presión , Sistema Enzimático del Citocromo P-450/efectos de los fármacos , Sistema Enzimático del Citocromo P-450/metabolismo , Ácido Gálico/metabolismo , Riñón/metabolismo , Hígado/metabolismo , Pulmón/metabolismo , Masculino , Microsomas/efectos de los fármacos , Microsomas/enzimología , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Especificidad de Órganos , Galato de Propilo/metabolismo , Ratas , Ratas WistarRESUMEN
Tannic acid, a naturally occurring plant phenol, was shown to inhibit the mutagenicity and/or tumorigenicity of several polycyclic aromatic hydrocarbons in mouse skin. In this study the effect of topical application of tannic acid on epidermal aryl hydrocarbon hydroxylase, glutathione S-transferase, and binding of benzo[a]pyrene (B[a]P) to epidermal DNA was compared with the activity of synthetic gallic acid esters. Single topical application of 8 mumol octyl and dodecyl gallate had no effect on the induction of aryl hydrocarbon hydroxylase, whereas propyl gallate and tannic acid increased the enzyme activity by nearly 200%. Application of the phenolics one hour before 0.2 mumol of B[a]P enhanced the enzyme activity, but the observed differences were not significant in comparison with a B[a]P-treated group of mice. Application of dodecyl and octyl gallates to mouse skin resulted in three- and twofold increases, respectively, in the activity of glutathione S-transferase. Combined treatment with dodecyl gallate and B[a]P also resulted in significant enhancement of this enzyme activity. Application of the same dose of tannic acid to mouse skin one hour before the application of 0.2 or 1 mumol of B[a]P afforded 60% inhibition of covalent benzo[a]pyrene-diol-epoxide binding to epidermal DNA. Gallic acid esters with the exception of dodecyl gallate were less effective inhibitors of benzo[a]pyrene-diol-epoxide binding, especially when the higher dose of B[a]P was used. These results indicate that the antitumorigenic activity of tannic acid involves the interaction of the ultimate carcinogen with DNA rather than an altered metabolism. The linkage between gallic acid and glucose in natural plant phenols is also more effective at inhibiting B[a]P binding to epidermal DNA than the linkage with the alkyl group in synthetic gallates.
Asunto(s)
Anticarcinógenos/farmacología , Antimutagênicos/farmacología , Benzo(a)pireno/química , Aductos de ADN/química , Ácido Gálico/farmacología , Taninos Hidrolizables/farmacología , Animales , Epidermis/enzimología , Ésteres , Femenino , Ratones , Estructura Molecular , Xenobióticos/metabolismoAsunto(s)
Benzo(a)pireno/toxicidad , Aductos de ADN , Daño del ADN , ADN/efectos de los fármacos , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Pulmón/efectos de los fármacos , Bazo/efectos de los fármacos , 7,8-Dihidro-7,8-dihidroxibenzo(a)pireno 9,10-óxido/análisis , 7,8-Dihidro-7,8-dihidroxibenzo(a)pireno 9,10-óxido/metabolismo , Animales , Benzo(a)pireno/análisis , Benzo(a)pireno/metabolismo , Carcinógenos Ambientales/análisis , Carcinógenos Ambientales/metabolismo , ADN/análisis , ADN/metabolismo , Inyecciones Intraperitoneales , Riñón/química , Riñón/metabolismo , Hígado/química , Hígado/metabolismo , Pulmón/química , Pulmón/metabolismo , Masculino , Ratas , Ratas Wistar , Espectrometría de Fluorescencia , Bazo/química , Bazo/metabolismoRESUMEN
The effect of pretreatment with o-, m- and p-toluidine on the drug-metabolizing enzymes of liver, kidney and lung in rats were investigated. The activities of microsomal aryl hydrocarbon hydroxylase (AHH), aminopyrine demethylase, NADPH-cytochrome c reductase, epoxide hydrolase, cytosolic glutathione S-transferase as well as the concentrations of cytochrome P-450 and cytochrome b5 were determined. The obtained results showed that o-toluidine increased the activity of AHH in all tested organs; a particularly marked increase was observed in the kidney. The activity of NADPH-cytochrome c reductase and the content of cytochrome b5 were enhanced by o-toluidine only in the liver. m-Toluidine enhanced the glutathione S-transferase activity while the p-isomer increased both the epoxide hydrolase and the glutathione S-transferase activities. p-Toluidine decreased the AHH and aminopyrine demethylase activities and the cytochrome P-450 content. These results may explain in part the previously reported observations on carcinogenic activity of o-toluidine.
Asunto(s)
Activación Enzimática/efectos de los fármacos , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Pulmón/efectos de los fármacos , Toluidinas/farmacología , Animales , Hidrocarburo de Aril Hidroxilasas/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Epóxido Hidrolasas/metabolismo , Glutatión Transferasa/metabolismo , Riñón/enzimología , Hígado/enzimología , Pulmón/enzimología , Masculino , Microsomas Hepáticos/enzimología , NADPH-Ferrihemoproteína Reductasa/metabolismo , Ratas , Ratas EndogámicasRESUMEN
The effect of two sesquiterpene lactones of the germacranolide group, eupatoriopicrin and hydroxyisonobilin, on the glycolytic metabolism of human lymphocytes stimulated by phytohemagglutinin was tested. Glucose and lactic acid levels as well as the activities of phosphofructokinase, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase, and lactate dehydrogenase were measured. Both lactones caused a decrease in glucose consumption and lactic acid formation as well as the inhibition of the tested enzymes. A stronger inhibitory effect was observed in the case of hydroxyisonobilin, particularly with regard to phosphofructokinase and glyceraldehyde 3-phosphate dehydrogenase.
Asunto(s)
Antineoplásicos/farmacología , Glucólisis/efectos de los fármacos , Linfocitos/metabolismo , Sesquiterpenos/farmacología , ADN/biosíntesis , Gliceraldehído-3-Fosfato Deshidrogenasas/antagonistas & inhibidores , Humanos , Técnicas In Vitro , L-Lactato Deshidrogenasa/antagonistas & inhibidores , Lactatos/metabolismo , Ácido Láctico , Linfocitos/efectos de los fármacosAsunto(s)
Clorofluorocarburos de Metano/toxicidad , Retardadores de Llama/toxicidad , Hígado/enzimología , Alanina Transaminasa/deficiencia , Alanina Transaminasa/metabolismo , Fosfatasa Alcalina/metabolismo , Animales , Aspartato Aminotransferasas/metabolismo , Bromoclorofluorocarbonos , Glucosa-6-Fosfatasa/metabolismo , Glucuronidasa/metabolismo , Masculino , Ratas , Ratas Endogámicas , Factores de TiempoRESUMEN
The authors compared the efficiency of isolation and the purity of lymphocytes obtained by the method of centrifugation in a gradient of ficoll and uropoline from blood obtained on ACD fluid and on heparin. Isolation of lymphocytes from the blood obtained on heparin was more efficient (60%) and useful. For removal of platelets it was necessary to use additional centrifugation in a saccharose gradient or application of aggregating agents during isolation of lymphocytes obtained on heparin or ACD fluid.