The influence of age and sex on selenium distribution and glutathione peroxidase activity in plasma and erythrocytes of selenium-adequate and supplemented rats.

The experiment was performed on Sprague-Dawley male rats weighting 203, 103 and 53 g, and female 99 g. Animals were fed for 2 weeks a diet containing 0.1 and 2.0 ppm of Se (Na2SeO3 added). It was observed that the daily Se intake per kg of BW is lowered with an increase in animals body weight. Se-supplementation caused a significant increase of Se content in plasma and red blood cells. The highest concentration of Se in plasma and in RBC was found in females. GSH-Px activity was higher in RBC of all male rats receiving a Se-supplemented diet, but not in females. In plasma these differences between Se-adequate and supplemented rats were significant in youngest male rats and in females. These results suggest that age and sex of rats affect the concentration of Se and GSH-Px activity in plasma and RBC of rats.