PERSONAL DE APOYO
FANELLI Silvia Laura
artículos
Título:
Liver nuclear and microsomal CyP2E1-mediated metabolism of xenobiotics in rats chronically drinking an alcohol containing liquid diet.
Autor/es:
MARÍA I. DÍAZ GÓMEZ; SILVIA L. FANELLI; AURORA M.A. DELGADO DE LAYÑO; JOSÉ A. CASTRO; GERARDO D.CASTRO
Revista:
TOXICOLOGY AND INDUSTRIAL HEALTH
Editorial:
SAGE Publications
Referencias:
Lugar: Londres; Año: 2006 vol. 22 p. 367 - 374
ISSN:
0748-2337
Resumen:
In the course of previous studies we reported the presence in highly purified nuclei of an metabolizing
group of enzymes (NEMS) leading to hydroxyl and 1-hydroxyethyl radicals. NEMS metabolized [14C]-ethanol
using NADPH as a factor to produce reactive metabolites covalently binding to nuclear proteins and lipids. NEMS
activity was significantly enhanced by repetitive alcohol drinking . In the present study we tested the possibility
that, during NEMS, an oxidative stress process harming nuclear components involving CYP2E1 was sparked.
Sprague Dawley male rats (125 150 g) were fed with a nutritionally adequate liquid diet containing ethanol to
provide 36% of total energy (standard Lieber-De Carli rat diet) for 28 days. Controls were pair fed with an isocaloric
diet without ethanol. Animals were sacrificed, livers excised and highly purified nuclear fractions prepared. Purity
of nuclei was assessed on the basis of lack of activity of marker enzymes for mitochondria (ICDh), for cytosol
(LDh); by phase contrast microscopy and by electron microscopy. The presence of CYP2E1 in those nuclear
preparations was further suggested by the determination of chlorzoxazone hydroxylation and its induction by
ethanol.We had previously reported their ability to metabolize other CYP2E1 known substrates such as CCl4;
chloroform; N-nitrosodimethylamine ; p-nitrophenol; aniline and o-toluidine. Now we report that after the repetitive
ethanol administration nuclear proteins are oxidized as evidenced by protein carbonyl and protein sulfhydryl
determinations. However, no lipid hydroperoxides were detected by the xylenol orange method. These protein
oxidative processes might result from decreased defenses in the nuclei as suggested by the t-butylhydroperoxideinduced
chemiluminiscence test. No increase in the 8-hydroxyguanine content in DNA was found, indeed, ethanol
drinking decreased it. No mutagenic effects of the ethanol drinking were detectable in liver tissue using the Comet
assay.