Selenium supplementation and blood rheological improvement in Japanese adults.
ABSTRACT In order to study the prevention effect of selenium in the development of cardiovascular disease, we investigated the effects of selenium supplementation on the blood rheological properties. Eleven healthy adults were administered with 200 microg of selenium in the form of selenium yeast per day for 1 wk. Before and after the supplementation, serum selenium concentration, glutathione peroxidase (GPx) activity, biochemical indices, and the blood fluidity of the subjects were measured. The blood fluidity was measured using a (microchannel array flow analyzer) by the passage time of 100 microL of heparinized whole blood through the microchannel array. The selenium supplementation significantly (p = 0.001) shortened the mean blood passage time from 44.0 +/- 5.7 to 37.5 +/- 2.8 s. Serum selenium concentration significantly (p = 0.008) increased from 109.8 +/- 10.2 to 124.5 +/- 16.7 microg/L. Meanwhile, the GPx activity did not increased significantly (p = 0.058). The mean GPx activity of the subjects before supplementation was 171.0 +/- 16.1 Deltammol NADPH/min/L and 180.9 +/- 17.8 Deltammol NADPH/min/L after supplementation. Factor analysis of the passage time and biochemical indices of the subjects showed that blood fluidity improvement was related to the metabolic modification of lipoproteins during the selenium supplementation. These results showed that selenium supplementation improved the blood fluidity, without increasing the GPx activity of the subjects.
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ABSTRACT: The chemical forms of selenium (Se) were determined in human plasma fractions. Human plasma was subjected to gel filtration using Sephadex G-150, and the first Se peak from this column was subsequently chromatographed on DEAE-Sephacel. The form of Se in the Se peak which eluted from this column was shown to be selenocysteine (SeCys). In a second approach human plasma was again subjected to gel filtration and the first Se peak was chromatographed on Affigel blue. SeCys was shown to be the form of Se in both the retained and unretained Se on this column. The second gel filtration Se peak was also chromatographed on Reactive Blue 2-Sepharose CL-6B and the form of Se which was not retained was also shown to be SeCys. However, the form which was retained was shown to be selenomethionine. Evidence is presented that there are three Se containing proteins in human plasma, which are selenoprotein P, glutathione peroxidase, and albumin.Journal of Inorganic Biochemistry 04/1991; 41(4):261-8. · 3.20 Impact Factor
Article: Regulation of selenoproteins.[show abstract] [hide abstract]
ABSTRACT: Selenium exerts its biological activity largely through selenoproteins, which contain the element in the form of selenocysteine. Five selenoproteins have been characterized in animal tissues and there is evidence that a number of others exist. Selenoprotein synthesis is a complex process that has been well characterized in prokaryotic systems but incompletely characterized in eukaryotic systems. Selenium deficiency causes a decrease in selenoproteins, but the decrease is not uniform and some selenoproteins are maintained better than others. The selenoprotein most sensitive to selenium deficiency is liver cGSH-Px. It contains a significant fraction of the selenium in the body, and decreased synthesis of it under deficiency conditions might serve to increase the selenium available for synthesis of selenoproteins that are more important to the survival of the animal than is cGSH-Px. The regulation of individual selenoproteins in selenium deficiency appears to be at the mRNA level. Factors that affect mRNA levels have not been completely characterized, but the fall in cGSH-Px mRNA in rat liver is not accompanied by decreased transcription, which suggests that it is regulated through changes in degradation.Annual Review of Nutrition 02/1993; 13:65-81. · 9.16 Impact Factor
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ABSTRACT: Selenium is present in plasma and tissues in specific and non-specific forms. The experiments reported here were carried out to clarify some factors that affect these forms of the element in plasma. A selenium-replete human subject was given 400 microg of selenium daily for 28 days as selenomethionine and, in a separate experiment, as selenate. The selenomethionine raised plasma and albumin selenium concentrations. Selenate did neither. The molar ratio of methionine to selenium in albumin was approximately 8000 under basal and selenate-supplemented conditions but 2800 after selenomethionine supplementation. This demonstrates that selenium from selenomethionine, but not selenium from selenate, can be incorporated into albumin, presumably as selenomethionine in the methionine pool. Selenocysteine incorporation into albumin was studied in rats using (75)Se-selenocysteine. No evidence was obtained for incorporation of (75)Se into albumin after exogenous administration or endogenous synthesis of (75)Se-selenocysteine. Thus, selenocysteine does not appear to be incorporated non-specifically into proteins as is selenomethionine. These findings are in support of selenomethionine being a non-specific form of selenium that is metabolized as a constituent of the methionine pool and is unaffected by specific selenium metabolic processes. No evidence was found for non-specific incorporation of selenium into plasma proteins when it was administered as selenate or as selenocysteine. These forms of the element appear to be metabolized by specific selenium metabolic processes.BioFactors 02/2001; 14(1-4):107-14. · 3.09 Impact Factor