ABSTRACT
Selenium (Se) is an essential trace element in the human body and plays critical roles in a wide variety of physiological processes via selenoproteins. Selenoproteins have antioxidant effects and are involved in regulating antioxidant activities. When serine is deficient, the glutathione antioxidant system is impaired. Selenium could not retrieve this antioxidant system, but surprisingly, Se could alleviate oxidative stress through an alternative antioxidant system, the thioredoxin system. Serine deficiency caused a significant decrease of glutathione (GSH)-Px activity in liver. Selenium significantly decreased Malondialdehyde (MDA) level in both serum and liver in mice fed a serine-deficient diet but had no effects on GSH level and GSH-Px activity. These results suggested that Se might alleviate oxidative stress caused by serine deficiency, but not through the glutathione antioxidant system. MDA, GSH contents, as well as glutathione peroxidase activity in serum and liver were analyzed using commercial kits according to the manufacturer’s instructions.
