Gastrointestinal absorption of inorganic mercuric compounds in vitro

Endo, Tokiko; Nakaya, Shozo; Kimura, Ryohei; Murata, Toshiro

doi:10.1016/0041-008x(86)90295-4

Cited by 21 publications

(30 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mercury deposition in the proximal part of jejunum with a peak at segment 7 and maximum labeling at 3 hr postdosage probably represents internalized mercury. The preferential labeling of the proximal part of jejunum, posterior to the outlets of the bile and pancreatic ducts agrees with results of previous investigations, which demonstrated enhanced absorption of mercury at increasing pH (7,13,14). Thus, the present study using the undisturbed intestinal system filled with digesta supports the studies using ligated perfused intestinal segments in vitro or in situ, indicating proximal jejunum as the major site for uptake of inorganic mercury; however, the absorption seems to occur in a larger part of jejunum than previously reported.…”

Section: Mercurysupporting

confidence: 81%

“…Step 2 has been found to be considerably slower than the initial binding and internalization for Hg (7). Foulkes (4) found that internalization of Hg bound to the active sites at the cell membranes must be rather fast, in agreement with previuos work (6,8).…”

Section: Introductionsupporting

confidence: 70%

“…The mag- In perfused intestinal sacs, the rate of step 2 for Hg++ and Cd++ has been estimated to be considerably lower than the rate of step 1 (7,9). The ratio between steps 1 and 2 for cadmium may be altered by induction of metallothionein (11 Whole-body counting was used to estimate the whole-body retention (WBR) of the dose given to each animal.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental localization of intestinal uptake sites for metals (Cd, Hg, Zn, Se) in vivo in mice.

Andersen

Nielsen

Sørensen

et al. 1994

Environ Health Perspect

View full text Add to dashboard Cite

The intestinal uptake process consists of two separable steps: transport over the luminal membrane into epithelial cytoplasm and transport over the basolateral membrane into serosal fluid. A compound's residence time in mucosal epithelial cytoplasm depends on rates of the two transport processes and, if the rate of the second step is low, on the rate of mucosal sloughing. Using remitting metal isotopes, in vivo labeling profiles of the intestinal tract were obtained from mice eating their normal diet. The results pertain to processes in the functioning, undisturbed intestinal tract. Single-dose chase experiments indicated that intestinal uptake processes were in fact studied. The labeling profiles varied considerably for different metals. Thus, Cd++ was absorbed mainly in duodenum and early jejunum, while Zn++ was taken up in jejunum and ileum. The uptake profile of Hg++ indicated most rapid uptake in proximal jejunum. Selenomethionine labeled the entire intestinal tract, most rapidly the duodenum, the following intestinal segments were labeled with falling rate. This experimental method is rapid and simple. Further studies aim at developing a quantitative model suited for studying interactions between essential and toxic metals at the level of intestinal metabolism. -Environ Health Perspect 102 (Suppl 3):199-206 (1994).

show abstract

Section: Mercurysupporting

confidence: 81%

Section: Introductionsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental localization of intestinal uptake sites for metals (Cd, Hg, Zn, Se) in vivo in mice.

Andersen

Nielsen

Sørensen

et al. 1994

Environ Health Perspect

View full text Add to dashboard Cite

show abstract

“…Subsequent co-administration of bile and HgCl 2 increased the absorption of Hg 2+ in the duodenum to levels similar to those observed in control rats. Furthermore, it was shown that the accumulation of Hg 2+ in the cells of the small intestine was greatest when the pH of the perfusion solution was 4.7 (Endo et al, 1984(Endo et al, , 1986. In contrast, when the pH of the perfusion solution was 8.0, the accumulation of Hg 2+ in the intestine was significantly lower than that at pH 4.7.…”

Section: Molecular Mimicry and The Intestinal Transport Of Hg 2+mentioning

confidence: 93%

Molecular and ionic mimicry and the transport of toxic metals

Bridges

Zalups

2005

Toxicology and Applied Pharmacology

677

460

View full text Add to dashboard Cite

Despite many scientific advances, human exposure to, and intoxication by, toxic metal species continues to occur. Surprisingly, little is understood about the mechanisms by which certain metals and metal-containing species gain entry into target cells. Since there do not appear to be transporters designed specifically for the entry of most toxic metal species into mammalian cells, it has been postulated that some of these metals gain entry into target cells, through the mechanisms of ionic and/or molecular mimicry, at the site of transporters of essential elements and/or molecules. The primary purpose of this review is to discuss the transport of selective toxic metals in target organs and provide evidence supporting a role of ionic and/or molecular mimicry. In the context of this review, molecular mimicry refers to the ability of a metal ion to bond to an endogenous organic molecule to form an organic metal species that acts as a functional or structural mimic of essential molecules at the sites of transporters of those molecules. Ionic mimicry refers to the ability of a cationic form of a toxic metal to mimic an essential element or cationic species of an element at the site of a transporter of that element. Molecular and ionic mimics can also be sub-classified as structural or functional mimics. This review will present the established and putative roles of molecular and ionic mimicry in the transport of mercury, cadmium, lead, arsenic, selenium, and selected oxyanions in target organs and tissues.

show abstract

“…We reported that an increase in pH increased the transport of HgCl, through the intestinal wall and the intestinal brush border membrane, while it decreased the binding of HgCl, to the wall and membrane (Endo et al 1986(Endo et al & 1988b. An increase in C1-concentration decreased the transport of HgCl, through the brush border membrane (Endo et al 1988b).…”

mentioning

confidence: 99%

Mechanisms of Absorption of Inorganic Mercury from Rat Small Intestine. III. Comparative Absorption Studies of Inorganic Mercuric Compounds in Vitro

Endo

Nakaya

Kimura

1990

Pharmacology & Toxicology

View full text Add to dashboard Cite

Abstract:The transport of various inorganic mercuric compounds (HgX,s) was compared in everted intestinal sacs and intestinal brush border membrane vesicles (BBMV) of the rat. The preparations were incubated in a medium containing lo-' M HgX, at pH 5.5,6.4 or 7.4, respectively. The order of transport through the intestinal wall at each pH (HgOAc), > HgCI, > Hg(SCN), > HgBr, > Hg(CN),) was the reverse order of their stability constants, and an increase in pH tended to increase the transport of HgX,. In the experiment with BBMV, similar results were obtained except for the transport of Hg(CN),. These results suggest that the extent of transport of a certain HgX, depends on its stability constant, and that the increase in pH promotes the transport possibly as a result of the conversion of HgX, to Hg(0H)X and Hg(OH12.

show abstract

Gastrointestinal absorption of inorganic mercuric compounds in vitro

Cited by 21 publications

References 9 publications

Experimental localization of intestinal uptake sites for metals (Cd, Hg, Zn, Se) in vivo in mice.

Experimental localization of intestinal uptake sites for metals (Cd, Hg, Zn, Se) in vivo in mice.

Molecular and ionic mimicry and the transport of toxic metals

Mechanisms of Absorption of Inorganic Mercury from Rat Small Intestine. III. Comparative Absorption Studies of Inorganic Mercuric Compounds in Vitro

Contact Info

Product

Resources

About