Selenoprotein P Concentration in Plasma is an Index of Selenium Status in Selenium-Deficient and Selenium-Supplemented Chinese Subjects

Abstract

Selenoprotein P, a selenium-rich plasma protein, is an index of selenium status in rats. Antibodies against human selenoprotein P were raised to study the protein and to develop a radioimmunoassay for it. A single collection of plasma from a healthy person in the United States contained 1.84 mumol selenium/L and was defined as containing 1 Unit (U) selenoprotein P/L. Removal of selenoprotein P from the reference plasma by an antibody column indicated that 0.81 mumol selenium/L, or 44% of the plasma selenium, was present as selenoprotein P. Work by others had determined that glutathione peroxidase accounted for 12% of plasma selenium. Stored plasma samples from selenium-deficient (Dechang County) and selenium-supplemented (Mianning County) populations in China were assayed for selenoprotein P. Boys aged 8-12 y had selenoprotein P concentrations of 0.10 +/- 0.04 U/L (n = 22) in Dechang and 0.39 +/- 0.17 U/L (n = 17) in Mianning. Supplementation with 100 micrograms selenium as selenate per day for 14 d raised those levels to 0.51 +/- 0.13 U/L in Dechang and to 0.76 +/- 0.27 U/L in Mianning. Similar results were obtained in men, and plasma selenium concentrations correlated with selenoprotein P concentrations. A study comparing indices of selenium status was conducted in the two counties. Selenoprotein P concentration in Dechang subjects (n = 79) was 36% of that in Mianning subjects (n = 117). For plasma glutathione peroxidase activity the value was 54%; for plasma selenium, 47%; and for whole blood selenium, 64%. We conclude that selenoprotein P is the major selenoprotein in human plasma and that its concentration is an index of selenium nutritional status that appears to be as sensitive as other indices in common use.

Selenium and antioxidant vitamin status of elderly German women

“…Studies indicate that serum selenium concentrations of around 1.1 mmol/l are associated with maximum activity and concentration of plasma selenoproteins (Hill et al, 1996;Duffield et al, 1999), while a serum concentration of around 1.5 mmol/l has been suggested as desirable because it may be optimal for cancer protection (Combs, 2001;Thomson 2004). Nearly 40% of the elderly women in our study exhibited a low selenium status (below 1.1 mmol/l) and more than 90% did not reach the desirable selenium level of 1.5 mmol/l.…”

Selenium status in Southern Tasmania

“…Selenium plasma levels for maximal glutathione peroxidase activity have been reported over the range 90-114 mg/l (Alfthan et al, 1991;Thomson et al, 1993;Duffield et al, 1999), whereas maximum selenoprotein P concentrations are reached around 83-118 mg/l (Marchaluk et al, 1995;Duffield et al, 1999), but may be as low as 71 mg/l in individuals with low selenium status (Hill et al, 1996). Rayman (1997) suggested a value of 100 mg/l as a threshold for nutritional adequacy although it has even been proposed that around 120 mg/l is a useful target for minimizing cancer risk (Combs, 2001).…”

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

“…The major selenoprotein in human plasma is selenoprotein P, which accounts for about 40% of the total plasma selenium Hill et al, 1996). 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).…”

“…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.…”