Kinetics of transepithelial movement of heavy metals in rat jejunum

Foulkes, E. C.; McMullen, Diane M.

doi:10.1152/ajpgi.1987.253.2.g134

Cited by 21 publications

(17 citation statements)

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“…Foulkes (1985,1988,2000) and Foulkes and McMullen (1987) have proposed a two-step mechanism of Cd 2+ transport across the luminal plasma membrane of enterocytes. The first step was postulated to involve binding of Cd 2+ to the plasma membrane.…”

Section: Mimicry and Intestinal Transport Of CD 2+mentioning

confidence: 99%

Molecular and ionic mimicry and the transport of toxic metals

Bridges

Zalups

2005

Toxicology and Applied Pharmacology

663

460

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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.

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Section: Mimicry and Intestinal Transport Of CD 2+mentioning

confidence: 99%

Molecular and ionic mimicry and the transport of toxic metals

Bridges

Zalups

2005

Toxicology and Applied Pharmacology

663

460

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“…Foulkes and McMullen (1987) proposed an intriguing mechanism for transport of metals across membranes. For example, the transport of Cd2+ across the intestinal membrane was postulated to consist of two distinct phases.…”

Section: New Considerations Regarding Mn Transportmentioning

confidence: 99%

Manganese and its Role in Parkinson’s Disease: From Transport to Neuropathology

et al. 2009

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Abstract:The purpose of this review is to highlight recent advances in the neuropathology associated with Mn exposures. We commence with a discussion on occupational manganism and clinical aspects of the disorder. This is followed by novel considerations on Mn transport (see also chapter by Yokel, this volume), advancing new hypotheses on the involvement of several transporters in Mn entry into the brain. This is followed by a brief description of the effects of Mn on neurotransmitter systems that are putative modulators of dopamine (DA) biology (the primary target of Mn neurotoxicity), as well as its effects on mitochondrial dysfunction and disruption of cellular energy metabolism. Next, we discuss inflammatory activation of glia in neuronal injury and how disruption of synaptic transmission and glial-neuronal communication may serve as underlying mechanisms of Mn-induced neurodegeneration commensurate with the cross-talk between glia and neurons. We conclude with a discussion on therapeutic aspects of Mn exposure. Emphasis is directed at treatment modalities and the utility of chelators in attenuating the neurodegenerative sequelae of exposure to Mn. For additional reading on several topics inherent to this review as well as others, the reader may wish to consult Aschner and Dorman (Toxicological Review 25:147-154, 2007) and Bowman et al. (Metals and neurodegeneration, 2009).

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“…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). Based on studies using jejunal segments, Foulkes (9) proposed a rapid absorption of cadmium from the intestinal lumen into mucosal cells and a 100-fold slower transfer of cadmium to the systemic circulation.…”

Section: Introductionmentioning

confidence: 57%

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

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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).

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Kinetics of transepithelial movement of heavy metals in rat jejunum

Cited by 21 publications

References 0 publications

Molecular and ionic mimicry and the transport of toxic metals

Molecular and ionic mimicry and the transport of toxic metals

Manganese and its Role in Parkinson’s Disease: From Transport to Neuropathology

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

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