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Journal ArticleDOI

Distribution and Dynamic Pathway of Selenium Species in Selenium-deficient Mice Injected with 82Se-enriched Selenite

10 Sep 2008-Analytical Sciences (The Japan Society for Analytical Chemistry)-Vol. 24, Iss: 9, pp 1117-1122
TL;DR: There were two pathways for the transfer of Se in mice; one was as SeAlb until 1 h after injections, and the other was as Sel-P from 6 to 72 h after injection.
Abstract: In order to elucidate Se metabolism in a living body, (82)Se-enriched selenite was injected intravenously into mice fed Se-adequate and -deficient diets. We studied the time-dependent changes in the distribution of the labeled Se in organs, red blood cells, and plasma. The total Se was determined by flow-injection ICPMS, and Se speciation analysis was conducted by micro-affinity chromatography coupled with low-flow ICPMS. Total Se in almost all organs, including liver, showed the maximum at 1 h after injection. From speciation analysis, exogenous (82)Se as Se-containing proteins other than selenoprotein P (Sel-P) (selenium containing albumin (SeAlb) and extra cellular glutathione peroxidase (eGPx)), peaked at 1 h and quickly decreased from 1 to 6 h after injection, whereas that as Sel-P, peaked at 6 h, and gradually decreased from 6 to 72 h after injection. We found that there were two pathways for the transfer of Se in mice; one was as SeAlb until 1 h after injection, and the other was as Sel-P from 6 to 72 h after injection.
Citations
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Journal ArticleDOI
TL;DR: This review summarizes recent insights into properties of individual selenoproteins such as tissue distribution, subcellular localization, and regulation of expression as well as potential roles the different seleniproteins play in human health and disease.
Abstract: Selenium (Se) is a nutritional trace mineral essential for various aspects of human health that exerts its effects mainly through its incorporation into selenoproteins as the amino acid, selenocysteine. Twenty-five selenoprotein genes have been identified in humans and several selenoproteins are broadly classified as antioxidant enzymes. As progress is made on characterizing the individual members of this protein family, however, it is becoming clear that their properties and functions are quite diverse. This review summarizes recent insights into properties of individual selenoproteins such as tissue distribution, subcellular localization, and regulation of expression. Also discussed are potential roles the different selenoproteins play in human health and disease.

455 citations


Cites background from "Distribution and Dynamic Pathway of..."

  • ...In one study, (82)Se was injected into mice intravenously and amounts of isotope determined over time for several different tissues [191]....

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Journal ArticleDOI
TL;DR: A review of analytical speciation methods developed for: the determination of oxidation states; organometallic compounds; coordination compounds; metal and heteroatom-containing biomolecules, including metalloproteins, proteins, peptides and amino acids; and the use of metal-tagging to facilitate detection via atomic spectrometry as mentioned in this paper.
Abstract: This is the fourth Atomic Spectrometry Update (ASU) to focus specifically on developments in elemental speciation and covers a period of approximately 12 months from January 2011. The International Union for Pure and Applied Chemistry (IUPAC) has evaluated speciation and provided a definition as follows: “speciation analysis is the analytical activity of identifying and/or measuring the quantities of one or more individual chemical species in a sample; the chemical species are specific forms of an element defined as to isotopic composition, electronic or oxidation state, and/or complex or molecular structure; the speciation of an element is the distribution of an element amongst defined chemical species in a system.” This review therefore deals with all aspects of the analytical speciation methods developed for: the determination of oxidation states; organometallic compounds; coordination compounds; metal and heteroatom-containing biomolecules, including metalloproteins, proteins, peptides and amino acids; and the use of metal-tagging to facilitate detection via atomic spectrometry. The review does not cover operationally defined ‘speciation’, which is correctly termed fractionation. As with all ASU reviews1–6 the coverage of the topic is confined to those methods that incorporate atomic spectrometry as the measurement technique. However, in the spirit of meeting the needs of the subject, material is incorporated that is not strictly “atomic spectrometry” but the separation or sample introduction technique used could also be coupled with an atomic spectrometry detector. For the most part, such procedures are those in which some form of molecular MS is used for speciation measurements. As the content of this Update shows, the field is now maturing as evidenced by the extent to which the speciation of particular elements or technique combinations have been the subject of review articles. However, it is becoming increasingly difficult to ascertain the analytical details of the methodologies applied in speciation analysis, particularly where the paper is published in an ‘application’ based journal.

73 citations

Journal ArticleDOI
TL;DR: The aim of this review is to present and evaluate the present knowledge of which selenium species are available to the general population in the form of food and common supplements and how these species are metabolized in mammals.
Abstract: The aim of this review is to present and evaluate the present knowledge of which selenium species are available to the general population in the form of food and common supplements and how these species are metabolized in mammals. The overview of the selenium sources takes a horizontal approach, which encompasses identification of new metabolites in yeast and food of plant and animal origin, whereas the survey of the mammalian metabolism takes a horizontal as well as a vertical approach. The vertical approach encompasses studies on dynamic conversions of selenium compounds within cells, tissues or whole organisms. New and improved sample preparation, separation and detection methods are evaluated from an analytical chemical perspective to cover the progress in horizontal speciation, whereas the analytical methods for the vertical speciation and the interpretations of the results are evaluated from a biological angle as well.

69 citations

Journal ArticleDOI
TL;DR: Se speciation was performed in 24 individual paired serum and cerebrospinal fluid samples from neurologically healthy persons, finding several Se species found in both sample types having following median values, which provide information about Se-species passage across neural barriers (NB): SePP-serum is significantly correlated to total Se-Serum when the latter was > 65 μg/L; however, Se PP-CSF appeared independent of SePP -serum.
Abstract: Se speciation was performed in 24 individual paired serum and cerebrospinal fluid (CSF) samples from neurologically healthy persons. Strong anion exchange (SAX) separation, coupled to inductively coupled plasma–dynamic reaction cell–mass spectrometry (ICP-DRC-MS), was employed. Species identification was done by standard matched retention time, standard addition and by size exclusion chromatography followed from SAX (2-D SEC-SAX-ICP-DRC-MS) and by SAX followed from CE-ICP-DRC-MS (2-D SAX-CE-ICP-DRC-MS). Limit of detection (LoD, 3 × standard deviation (SD) of noise) was in the range of 0.026–0.031 μg/L for all investigated species and thus was set uniformly to 0.032 μg/L. Quality control for total Se determination was performed by analysing control materials “human serum” and “urine”, where determined values met target values. Several Se species were found in both sample types having following median values (sequence: serum/CSF, each in μg Se/L): total Se, 58.39/0.86; selenoprotein P (SePP), 5.19/0.47; Se-methionine (SeM), 0.23/ 65 μg/L; however, SePP-CSF appeared independent of SePP-serum. For Se-HSA-serum versus (vs.) Se-HSA-CSF, a weak linear relationship was found (r2 = 0.1722). On the contrary, for anti-oxidative Se-enzymes, higher r2 values were calculated: GPx-serum vs. GPx-CSF, r2 = 0.3837; TrxR-serum vs. TrxR-CSF, r2 = 0.6293. Q-Se-species values (= ratios of CSF-Se-species/serum-Se-species) were compared with the Q-Alb value (HSA-CSF/HSA-serum = clinical index of NB integrity) for deeper information about NB passage of Se species. The Q-Se-HSA value (3.8 × 10−3) was in accordance to the molecular mass dependent restriction at NB (Q-Alb at 5.25 × 10−3). Increased Q values were seen for TrxR (21.3 × 10−3) and GPx (8.3 × 10−3) which are not (completely) explained by molecular size. For these two anti-oxidative Se-enzymes (GPx, TrxR), we hypothesize that there might be either a facilitated diffusion across NB or they might be additionally synthesized in the brain.

63 citations

Journal ArticleDOI
TL;DR: Higher Se intake could efficiently reduce Cd retention during the suckling period, andSelenium levels in plasma, brain, and kidney of suckling rats also decreased.
Abstract: Selenium (Se) reduces cadmium (Cd) toxicity in adult animals, but its effects in newborn animals are still unknown. This study investigated Cd (as CdCl2) absorption, distribution, and retention in suckling rats receiving oral Se supplementation (as Na2SeO3) in equimolar doses (8 μmol Cd and/or Se per kg b.w./day). Selenium was given either before and during Cd exposure (Sepre + Cd group; pre-treatment group) or only during Cd exposure (Se + Cd group). Rats were treated from postnatal day (PND) 6–14 as follows: controls (H2O, PND 6–14), Se (PND 10–14), Cd (PND 10–14), Sepre + Cd (Se PND 6–14 + Cd PND 10–14) and Se + Cd (Se + Cd PND 10–14). Selenium supplementation, especially pre-treatment, decreased Cd levels in the blood, brain, liver and kidney of suckling rats. Selenium levels in plasma, brain, and kidney also decreased. These findings suggest that higher Se intake could efficiently reduce Cd retention during the suckling period.

44 citations


Cites background from "Distribution and Dynamic Pathway of..."

  • ...As the liver is the main organ for Se accumulation (Shigeta et al. 2008), it is no surprise that Se levels were higher there than in the kidney and brain even when the pups were exposed to Cd....

    [...]

References
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Journal ArticleDOI
TL;DR: In this article, it was shown that high doses of selenite resulted in induction of 8-hydroxydeoxyguanosine (8-OHdG) in mouse skin cell DNA and in primary human keratinocytes.

660 citations

Journal ArticleDOI
TL;DR: Overall, inadequate intake and status of these vitamins and minerals may lead to suppressed immunity, which predisposes to infections and aggravates malnutrition.
Abstract: Adequate intakes of vitamins and trace elements are required for the immune system to function efficiently. Micronutrient deficiency suppresses immune functions by affecting the innate T-cell-mediated

626 citations

Journal ArticleDOI
TL;DR: The results suggest that Se-P from liver provides selenium to several tissues, especially testis and brain, and indicate that transport forms of seenium other than Se-p exist because selenia levels of all tissues except testis responded to increases of dietary selenIUM in Sepp −/− mice.

425 citations

Journal ArticleDOI
TL;DR: The data reveal that SePP plays a pivotal role in delivering hepatic selenium to target tissues and thatSelenium content was elevated in liver, but low in plasma and other tissues, and selenoenzyme activities changed accordingly.
Abstract: Selenoprotein P (SePP), the major selenoprotein in plasma, has been implicated in selenium transport, selenium detoxification or antioxidant defence. We generated SePP-knockout mice that were viable, but exhibited reduced growth and developed ataxia. Selenium content was elevated in liver, but low in plasma and other tissues, and selenoenzyme activities changed accordingly. Our data reveal that SePP plays a pivotal role in delivering hepatic selenium to target tissues.

396 citations

Journal ArticleDOI
Kazuo T. Suzuki1
TL;DR: The metabolism of selenium in the body was reviewed from the viewpoint of metabolomics based on speciation studies and recent results contradicted this.
Abstract: Selenium is a trace element essential for the normal function of the body. This metalloid is quite unique in its metabolism compared with typical essential metals such as copper and zinc. In the present communication, the metabolism of selenium in the body was reviewed from the viewpoint of metabolomics based on speciation studies. Both inorganic and organic forms of slenium can be the nutritional source, and they are transformed to the common intermediate, selenide or its equivalent. Selenite and selenate are reduced simply to selenide for further utilization and/or excretion. On the other hand, organic selenocysteine is directly lysed to selenide, while selenomethionine is transformed to selenocysteine (trans-selenation pathway), similarly to the trans-sulfuration pathway for methionine to cysteine, and then lysed to selenide. Selenide is known to be transformed to selenocysteine on tRNA, and the selenocysteinyl residue is incorporated into selenoprotein sequences by the codon specific to selenocysteine, UGA. Diverse selenium chemicals in foods seem to be recognized as selenium species and transformed to selenide, and then utilized for the synthesis of selenoproteins. Surplus selenium is methylated stepwise to methylated selenium metabolites from the common intermediate selenide. The major urinary metabolite is 1β-methylseleno-N-acetyl-D-galactosamine (selenosugar). Trimethylselenonium has been recognized as the urinary metabolite excreted in response to excessive doses and as a biological marker for excessive doses. However, recent results contradicted this.

222 citations