Distribution of Selenium in Plasma of French Women: Relation to Age and Selenium Status (Technical Briefs‪)‬

Human plasma selenium is associated with three proteins: selenoprotein P (Se-P), glutathione peroxidase (isoform 3 of GSHPx), and albumin (1,2). Most of the methods used to study the distribution of plasma selenium among these proteins are based on gel filtration (3-6) or on affinity chromatography (2,7-9). Gel filtration is less sensitive, resolves less well, and has given higher results than affinity chromatography for GSHPx (7). Affinity chromatography is time-consuming and unsuitable for routine analyses. The only direct method to determine plasma Se-P is a RIA (10,11). We developed an indirect determination of Se-P. After plasma albumin-globulin separation, the selenium content of the albumin fraction was measured and the selenium content of plasma Se-P was deduced from the total plasma selenium minus the sum of selenium coming from plasma albumin and GSHPx. In a previous study, we showed that plasma selenium was significantly decreased in a group of institutionalized elderly women compared with a free-living group and a group of young adult women living in the same area (12). To investigate the etiology of the differences in selenium status among these groups, we studied plasma selenium distribution among the three protein compartments.