Selenoprotein P in serum as a biochemical marker of selenium status

Abstract

Some characteristics of a radioimmunoassay of selenoprotein P (a major selenoprotein in human serum) are described. Polyclonal antibodies generated in rabbits were used and goat anti-rabbit-IgG antiserum was used as a second antibody. Depending on the concentration of selenoprotein P, 1-10 microliters of human serum were used in the assay. The relative standard deviation for the concentration of selenoprotein P was 6.3% between assays and 7.7% within assays. Different animal sera gave no significant interference, indicating that the antibodies did not react with non-human analogues of selenoprotein P. No indication of cross-reactivity could be found concerning extracellular glutathione peroxidase (another selenoprotein in serum). Addition of increasing amounts of normal human serum and partially purified selenoprotein P to the radioimmunoassay resulted in parallel curves. Incubation at 4 degrees C gave somewhat higher binding of labelled selenoprotein P than incubation at room temperature. The epitope, recognized by the antibodies, was apparently stable after storage of serum (in the frozen state for years, and in the cold for months). No significant amount of selenoprotein P could be demonstrated in red blood cells, and analysis of haemolysed whole blood gave expected data. Investigations of selenium status in different study groups indicated that in most cases the concentration of selenoprotein P in serum was positively correlated to that of glutathione peroxidase and serum selenium. In an intervention study, where subjects decreased their selenium intake to 50%, the serum levels of glutathione peroxidase and selenium decreased, but no significant decrease of selenoprotein P could be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma levels of selenium, selenoprotein P and glutathione peroxidase and their correlations to fish intake and serum levels of thyrotropin and thyroid hormones: A study on Latvian fish consumers

“…Selenoprotein P and glutathione peroxidase Selenoprotein P and extracellular glutathione peroxidase were measured by radioimmunoassays as described elsewhere (Huang & A Ê kesson, 1993;Persson-Moschos et al, 1995). The concentration of selenoprotein P was expressed in arbitrary units (au) relative to a standard of pooled plasma.…”

Plasma selenoprotein P levels of healthy males in different selenium status after oral supplementation with different forms of selenium

“…Selenoprotein P levels in the plasma samples were measured with a radioimmunoassay (Persson-Moschos et al, 1995a), and the concentration of selenoprotein P was expressed in arbitrary units (au) relative to a standard of pooled plasma. The intra-assay coef®cient of variation (cv) was 3.8% and the inter-assay cv was 6.6%.…”

“…Its concentration in plasma re¯ects the selenium status in healthy subjects (Marchaluk et al, 1995;Persson-Moschos et al, 1995a;Hill et al, 1996) as well as in patients with low selenium status (Persson-Moschos et al, 1995b;Rannem et al, 1996). Selenoprotein P is a selenium-rich protein, which contains up to ten selenocysteine residues per polypeptide chain, compared to one selenocysteine residue in other characterised selenoproteins.…”

Low selenium status is associated with the occurrence of the pregnancy disease preeclampsia in women from the United Kingdom

“…The greater importance of selenoprotein P, however, is indicated by the fact that its concentration was preserved relative to that of plasma GPx (GPx-3) in subjects reducing their selenium intake. 29 Relatively low selenium status prior to pregnancy (as measured by toenail selenium concentration) may adversely affect the functional activity of the selenoproteins, reducing their protective effect against oxidative stress. This situation may be exacerbated by the expansion in plasma volume and reduced plasma selenium concentration normally associated with pregnancy.…”