Selenium levels and glutathione peroxidase activities in blood in an andean high-altitude population.

Selenium (Se) levels in blood (whole blood, erythrocytes and serum) and blood glutathione peroxidase (GSH-Px) activity were investigated in people living at high altitude in Bolivia (4,000 m above sea level). These parameters were compared to those of people living at low altitude (300 m above sea level). The Se levels in whole blood of the high-altitude subjects did not differ significantly from those of the low-altitude subjects. However, the Se levels in erythrocytes were significantly lower in the high-altitude subjects than in the low-altitude subjects, whereas serum Se levels were higher in the high-altitude subjects than in the low-altitude subjects. GSH-Px activity (Unit/g Hb) was significantly lower in the high-altitude subjects than in the low-altitude subjects. The mean corpuscular Hb concentration (MCHC), an indicator of the age of erythrocytes, in the high-altitude subjects was significantly higher than in the low-altitude subjects. These results show that the GSH-Px activity in the blood of the high-altitude subjects is relatively low. This may be due to their aged erythrocytes and/or to relatively low Se intake in the high-altitude population compared with low-altitude population.