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Titolo:
Evaluation of methylmercury biotransformation using rat liver slices
Autore:
Yasutake, A; Hirayama, K;
Indirizzi:
Natl Inst Minamata Dis, Biochem Sect, Kumamoto 8670008, Japan Natl Inst Minamata Dis Kumamoto Japan 8670008 t, Kumamoto 8670008, Japan Kumamoto Univ, Coll Med Sci, Kumamoto 8620976, Japan Kumamoto Univ Kumamoto Japan 8620976 ll Med Sci, Kumamoto 8620976, Japan
Titolo Testata:
ARCHIVES OF TOXICOLOGY
fascicolo: 7, volume: 75, anno: 2001,
pagine: 400 - 406
SICI:
0340-5761(200109)75:7<400:EOMBUR>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUB-MITOCHONDRIAL PARTICLES; INORGANIC MERCURY; ETHYL MERCURY; SUPEROXIDE ANION; METHYL MERCURY; AMINO-ACIDS; DEGRADATION; CHLORIDE; TISSUES; BRAIN;
Keywords:
methylmercury; biotransformation; reactive oxygen; liver slice; mitochondria;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
25
Recensione:
Indirizzi per estratti:
Indirizzo: Yasutake, A Natl Inst Minamata Dis, Biochem Sect, Kumamoto 8670008, Japan Natl Inst Minamata Dis Kumamoto Japan 8670008 8670008, Japan
Citazione:
A. Yasutake e K. Hirayama, "Evaluation of methylmercury biotransformation using rat liver slices", ARCH TOXIC, 75(7), 2001, pp. 400-406

Abstract

To examine the demethylation reaction of methylmercury (MeHg); in rat liver, slices prepared from MeHo-treated rats were incubated in L-15 medium under 95% O-2/5% CO2 atmosphere. During the incubation, the amount of inorganic Hg in the slices markedly increased in a time-dependent manner, although the concentration of total Hg remained unchanged. Since the C-Hg bond in MeHg was demonstrated to be cleaved by the action of some reactive oxygen species, the effects on MeHg demethylation of several reagents that could modify reactive oxygen production were examined in the present system. Methylviologen was found to be an effective enhancer of the demethylation reaction with only a minor effect on lipid peroxidation. On the other hand, ferrous ion added to the medium showed no effect on demethylation in the presence or absence of methylviologen, although lipid peroxide levels were increased significantly by ferrous ion. Similarly, deferoxamine mesylate, which effectively suppressed the increase in lipid peroxide levels, also had no effecton demethylation. Furthermore, hydroxy radical scavengers, such as mannitol and dimethylsulfoxide, had no effect on inorganic Hg production. Rotenone, an inhibitor of complex I in the mitochondrial electron transport system,increased levels of both inorganic Hg and lipid peroxide. However, other inhibitors, such as antimycin A, myxothiazole and NaCN, significantly suppressed the demethylation reaction. Cell fractionation of the MeHg-treated ratliver revealed that the ratio of inorganic Hg to total Hg was highest in the mitochondrial fraction. Furthermore, superoxide anion could degrade MeHgin an organic solvent but not in water. These results suggested that the demethylation of MeHg by the liver slice would proceed with the aid of superoxide anion produced in the electron transfer system at the hydrophobic mitochondrial inner membrane. Furthermore, the involvement of hydroxy radicals, which have been demonstrated to be effective in cleaving the C-Hg bond inthe aqueous media, might be minimal. Here, we also demonstrated that liverslices are a useful experimental model for mimicking the MeHg biotransformation reaction.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/01/20 alle ore 14:42:47