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

Seko, Yoshiyuki; Takahashi, Masako; Hasegawa, Tatsuya; Miura, Teiji

doi:10.1248/jhs.47.508

Cited by 8 publications

(8 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the concentration of mercury in the intestine and stomach was particularly low. Contrary to our assumption that the intestine should accumulate much mercury, as this organ absorbs mercury as well as nutrients, 18 this result shows the converse. In the internal organs, except for heart and spleen, the mercury concentration had a tendency to decrease with body growth.…”

Section: Resultscontrasting

confidence: 99%

Possibility for decreasing of mercury content in bluefin tuna Thunnus orientalis by fish culture

et al. 2007

View full text Add to dashboard Cite

The bluefin tuna tested were reared for 22 months from eggs before the beginning of the experiment, and sampling was performed every 3 months over the following year. The experimental results showed that the mercury concentration in the muscle ranged from 0.32 to 0.85 mg/g, which is lower than that found in wild bluefin tuna of a similar size. Increase in the mercury concentration corresponding to the increase in body weight was not shown, and it was quite different with wild bluefin tuna. Furthermore, no significant relationship was found between the lipid concentration and the mercury concentration in muscle. Among the internal organs of cultured bluefin tuna, the heart (0.32-0.66 mg/g), liver (0.43-0.99 mg/g) and spleen (0.59-1.0 mg/g) contained higher concentrations of mercury. It was estimated that the full-cycle cultured bluefin tuna had been fed small fish containing lower concentrations of mercury, and that the mercury concentration of tuna would be almost equal throughout the year because the effect of mercury accumulation would be weakened by body growth. Therefore, it was concluded that selecting diet fish species might decrease mercury contents in cultured bluefin tuna.

show abstract

Section: Resultscontrasting

confidence: 99%

Possibility for decreasing of mercury content in bluefin tuna Thunnus orientalis by fish culture

et al. 2007

View full text Add to dashboard Cite

show abstract

“…In fact, it has been reported that CH 3 Hg has a great affinity for thiol groups of proteins, particularly for cysteine residues (Bridges and Zalups, 2006;Hong et al, 2012;Wagner et al, 2010). On the other hand, in the intestinal tract CH 3 Hg can be transformed into inorganic mercury by the intestinal microflora (Seko et al, 2001), and therefore inhibit AQPs. Only two AQPs are not inhibited by mercury: AQP4 and AQP6.…”

Section: Discussionmentioning

confidence: 99%

Impaired aquaporins expression in the gastrointestinal tract of rat after mercury exposure

Bottino

Vázquez

Devesa

et al. 2015

J of Applied Toxicology

View full text Add to dashboard Cite

The main route of exposure to mercury in humans is through the diet. Consequently, the gastrointestinal mucosa is exposed to the mercurial forms, where they cause intestinal fluid accumulation, mucosal injuries and diarrhea. The relationship between inorganic mercury (HgCl2 ) and methylmercury (CH3 HgCl) exposure and water movement in the gastrointestinal tract is still unexplored. The leading role of aquaporins (AQPs) in the rapid bidirectional movement of fluid in the gastrointestinal tract of mammals is well established. The present study evaluates the effect of HgCl2 and CH3 HgCl exposure on AQP expression in different portions of the gastrointestinal tract of rats treated by gavage (5 mg kg(-1) of mercury species, single dose, 4 days). The results show that mercury species reduce mRNA and protein levels of AQPs in different parts of the gastrointestinal tract. In the stomach, treated rats show a significant reduction of expression of AQP3 (80-90% for mRNA and 50% for protein) and AQP4 (95-99% for mRNA and 20-40% for protein). In the small and large intestine, treated rats experience a significant reduction of AQP3 and AQP7 expression. Protein contents of both AQPs are reduced in similar proportions in jejunum (AQP3: 40-50%; AQP7: 45-50%) and colon (AQP3: 35-40%; AQP7: 45-60%), regardless of the treatment. Our results indicate that some AQPs are downregulated in the rat gastrointestinal tract by mercury exposure, suggesting a possible role of AQPs in the development of mercury gastrointestinal symptoms.

show abstract

“…Part of the MeHg in the liver is secreted into the intestinal tube via the bile duct, and then the gut flora would convert MeHg to inorganic Hg (Seko et al, 1981(Seko et al, , 2001). Most of the inorganic Hg thus formed would appear in the feces without the intestinal reabsorption.…”

Section: Resultsmentioning

confidence: 99%

Demethylation of methylmercury and the enhanced production of formaldehyde in mouse liver

Uchikawa

Kanno²,

Maruyama³

et al. 2016

J. Toxicol. Sci.

View full text Add to dashboard Cite

-Methylmercury (MeHg) is gradually changed to inorganic Hg after demethylation in animal tissues, and a selective quantification of inorganic Hg in the tissues is necessary to detect the reaction. We detected inorganic Hg formation in liver and kidney of mouse as early as 24 hr after MeHg injection. As an example of biological demethylation, the cytochrome P450 (P450)-mediated N-demethylation of drugs has been well documented, and formaldehyde was detected as a reaction product. Here we incubated mouse liver homogenate with added MeHg and observed a dose-dependent production of formaldehyde, as well as inorganic Hg formation. Since the amount of formaldehyde was approx. 500 times higher than that of the inorganic Hg that formed, the formaldehyde production would be stimulated by inorganic Hg formed from MeHg. We observed that inorganic Hg caused formaldehyde production, and it was enhanced by L-methionine and sarcosine. Thus, some biomolecules with S-methyl and N-methyl groups may function as methyl donors in the reaction. Using subcellular fractions of mouse liver, we observed that microsomal P450 did not participate in the demethylation of MeHg, but the greatest activity was located in the mitochondria-rich fraction. The addition of superoxide anion in the reaction mixture significantly enhanced the formaldehyde production, whereas Mn-superoxide dismutase depressed the reaction. Our present findings demonstrated that inorganic Hg formed by MeHg demethylation in mouse liver stimulated the endogenous formaldehyde production, and we observed that MeHg demethylation could be estimated by a formaldehyde analysis. Our results also suggested that superoxide anion is involved in the reaction.

show abstract

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

Cited by 8 publications

References 14 publications

Possibility for decreasing of mercury content in bluefin tuna Thunnus orientalis by fish culture

Possibility for decreasing of mercury content in bluefin tuna Thunnus orientalis by fish culture

Impaired aquaporins expression in the gastrointestinal tract of rat after mercury exposure

Demethylation of methylmercury and the enhanced production of formaldehyde in mouse liver

Contact Info

Product

Resources

About