Biotransformation of methylmercury in vitro.

Ishihara, Nobuo; Suzuki, Tsuguyoshi

doi:10.1620/tjem.120.361

Cited by 16 publications

(9 citation statements)

References 8 publications

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“…The most probable alternative sites of CHaHgCl metabolism are the liver and kidney, since chopped tissue preparations of these organs have been shown to possess the ability to metabolize methylmercury. 17 Our results are in agreement with those of Nakamura et al,10 who showed, using germ-free and conventional mice, that in the former animals Hg excretion was decreased in the feces after a single oral dose of CHaHgCI, and that there were increases in the amounts of Hg accumulated in certain organs. Norseth' s 3, conflicting findings that there were no differences in biotransformation of CHa HgCI in germ-free and conventional rats might not be entirely valid, since the route of administration was not oral (which gives the maximum opportunity for the gut flora to metabolize the mercurial), but subcutaneous.…”

Section: Resultssupporting

confidence: 93%

Tissue Content of Mercury in Rats Given Methylmercuric Chloride Orally: Influence of Intestinal Flora

Rowland¹,

Davies²,

Evans³

1980

Archives of Environmental Health: An International Journal

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The effect of intestinal flora on the absorption and dispositon of mercury in tissues was investigated using conventional rats, and rats treated with antibiotics to eliminate their gut flora. Antibiotic-treated rats given [203Hg]-labeled methylmercuric chloride orally had significantly more mercury in their tissues, especially in kidney, brain, lung, blood, and skeletal muscle, and also excreted less mercury in the feces than conventional rats. Furthermore, in the kidneys of the antibiotic-treated rats, the proportion of mercury present as organic mercury was greater than in the kidneys of the conventional rats. The results suppport the hypothesis that the metabolism of methylmercuric chloride by the gut flora reduces the tissue content of mercury. When rats were administered 10 mg methylmercuric chloride/kg . day for 6 days, four of five of those given antibiotics developed neurological symptoms of toxicity, whereas only one of five conventional rats given methylmercuric chloride was affected.

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Section: Resultssupporting

confidence: 93%

Tissue Content of Mercury in Rats Given Methylmercuric Chloride Orally: Influence of Intestinal Flora

Rowland¹,

Davies²,

Evans³

1980

Archives of Environmental Health: An International Journal

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“…2,3) Intestinal flora plays important roles not only in decomposition of organic mercury (o-Hg) but also in fecal excretion of total mercury (t-Hg) in animals administered methylmercury as reviewed by Rowland 4) and Tanaka-Kagawa, 5) though animal tissues can decompose methylmercury in vitro [6][7][8] and in vivo. [9][10][11] In the case of phenylmercury, the mercury was decomposed much faster than methylmercury, and intestinal flora did not participate in the decomposition nor in the fecal excretion of mercury.…”

Section: Introductionmentioning

confidence: 99%

Intestinal Absorption of Mercury in Vitro from Intestinal Contents of Methylmercury Administered Mice.

Seko¹,

Takahashi

Hasegawa³

et al. 2001

JOURNAL OF HEALTH SCIENCE

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Intestinal flora plays an important role in the decomposition and fecal excretion of methylmercury. The assumed mechanism is that decomposition of organic mercury (o-Hg) to inorganic mercury (i-Hg) by intestinal flora in cecum decreases the reabsorption of mercury in large intestines. To confirm this hypothesis, we examined the large intestinal mercury absorption in vitro from intestinal contents of methylmercury administered mice. Methylmercury (2 mg Hg/kg) was administered intraperitoneally to adult female mice, and the contents of small intestine (ileum) and cecum were taken out 24 hr after the administration. Ratios of organic mercury to total mercury in small intestinal content and cecal content were 86% and 49%, respectively. Contents fo both samall intestine and cecum were packed into cecum and colon of normal mice, respectively, and were incubated in a medium (Tyrode's solution) at 37°C for 2 hr. 73% of total mercury (t-Hg) was absorbed from small intestinal content into the cecum and medium after the incubation. On the other hand, only 34% of t-Hg was absorbed from cecal content; most i-Hg remained unabsorbed. However, the absorption rate of t-Hg increased to 57% when the cecal content from antibiotics treated mice was used, because of the high percentage (90%) of o-Hg contained. These results suggest that o-Hg in small intestinal and cecal contents can be reabsorbed by cecum and colon in vivo, and that the decomposition of o-Hg to i-Hg by intestinal flora decreases the intestinal reabsorption rate of t-Hg in methylmercury exposed mice.

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“…2) No studies have dealt with the role of selenite in methylmercury degradation in vivo, but a few experiments have suggested increased degrada tion. 3,4) This study aimed to examine the role of co administered selenite and methylmercury in in organic mercury accumulation by changing the dose of selenite.…”

Section: Accumulationmentioning

confidence: 99%

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Suzuki¹,

YAMAMOTO²

1984

Sangyo Igaku

Self Cite

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Mice were fed methylmercury (10nmol/g feed) and selenite (0,8,20 or 50nmol/ml drinking water) for one or two weeks. Doses of selenite and duration of feeding were determining factors of total mercury and inorganic mercury concentrations in organs.Increasing the dose of selenite produced the following results: concentration of total mercury in creased in the brain and liver and decreased in the blood, kidneys and spleen; concentration of inorganic mercury increased in the liver and spleen, decreased in the kidneys, and remained unchanged in the brain; the rate of inorganic mercury to total mercury increased in the liver and spleen, decreased in the brain, and remained unchanged in the kidneys. In every case, inorganic mercury in the blood was below the detection limit.

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Biotransformation of methylmercury in vitro.

Cited by 16 publications

References 8 publications

Tissue Content of Mercury in Rats Given Methylmercuric Chloride Orally: Influence of Intestinal Flora

Tissue Content of Mercury in Rats Given Methylmercuric Chloride Orally: Influence of Intestinal Flora

Intestinal Absorption of Mercury in Vitro from Intestinal Contents of Methylmercury Administered Mice.

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