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

Abstract

Experimental ChemicalsThe Se-enriched selenite was injected intravenously into mice fed Seadequate 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.

Isolation of Selenoprotein-P and Determination of Se Concentration Incorporated in Proteins in Human and Mouse Plasma by Tandem Heparin Affinity and Size-exclusion Column HPLC-ICPMS

“…The concentrations of Se were determined by means of a one-point standard calibration method with a 100-μL aliquot of analytical standards of selenite after passing through the column in both the mobile-phase conditions to correct for any signal enhancement due to coexisting carbon. 14 All analyses were performed in triplicate.…”

“…The digestion procedure was described in a previous paper. 14 The digested samples were diluted with ultrapure water (18.4 MΩ, Milli-Q Element, Nihon Millipore K.K., Tokyo, Japan) after addition of In as an internal standard. Mathematical correction of the spectral interferences of 81 Br 1 H, enhancement effect by coexisting carbon, and internal standardization were performed in this order, as described elsewhere.…”

“…Because heparin interacts with Sel-P in plasma, 13 heparin AF HPLC has been used for the speciation analysis of Sel-P to distinguish it from other, non-heparin-binding, selenoproteins. 14,15 However, AF HPLC-ICPMS has many limitations. For example, only certain proteins can be separated from others with an AF-based column.…”

Speciation analysis by small-bore HPLC coupled to ICP-MS

“…In this study, the simultaneous determination of glutathione peroxidase (GPx), selenoprotein P (SelP) and selenoalbumin (SeAlb) in human serum has been carried out in the shortest analysis time ever reported. This type of small-bore column has also been used for a rapid and effective determination of SelP in human [55] and mouse [56] plasma.…”

Quantification of Proteins by Measuring the Sulfur Content of Their Constituent Peptides by Means of Nano HPLC-ICPMS

“…From the viewpoint of atomic mass spectrometry, ICPMS has been used to quantify metal proteins such as metallothionein and selenoproteins. [11][12][13][14][15][16] In addition to metallic and metalloid elements, non-metal elements, such as sulfur (S) and phosphorus (P), are considered to be important for protein quantification. In particular, S is a key element for protein and peptide quantification because most proteins contain 2 S-containing amino acids, cysteine and methionine; cysteine is present in 96.6% of human proteins, and methionine is present in 98.8%.…”