Distribution of selenium and glutathione peroxidase in blood fractions from humans, rhesus and squirrel monkeys, rats and sheep.

The distribution of selenium and glutathione peroxidase (GSH-Px) was investigated in blood fractions from humans, rhesus and squirrel monkeys, sheep and rats by gel filtration (Sephadex G-150). The majority of selenium in plasma and erythrocytes from sheep, squirrel monkeys and rats cochromatographed with GSH-Px. In contrast, selenium in plasma from humans and rhesus monkeys cochromatographed with two non-GSH-Px proteins and nearly all of the selenium in erythrocytes cochromatographed with the hemoglobin peak. A significant amount of GSH-Px activity in rhesus monkey and human erythrocytes also cochromatographed with the hemoglobin fraction, but very little GSH-Px coeluted with hemoglobin from squirrel monkeys, ovine and rat blood. The results suggest that GSH-Px activity may not be a good measure of selenium status in higher primates.