Effects of dietary selenium and vitamin E on glutathione concentrations and glutathione S-transferase activities in chick liver and plasma

Abstract

Listen

Translate article

Studies were conducted to determine the effects of the antioxidant nutrients selenium (Se) and vitamin E (VE) on the concentrations of glutathione (GSH) and activities of two GSH-metabolizing enzymes, Se-dependent GSH-peroxidase (SeGSHpx) and GSH S-transferase (GSH-T), in the chick. The hepatic activity of GSH-T, assayed using 1-chloro-2,4-dinitrobenzene as substrate (GSH-T CDNB), was greater in chicks depleted of both Se and VE than in chicks fed adequate levels of either nutrient. This effect was only observed when the Se deficiency was severe enough to result in a very substantial loss of SeGSHpx activity (e.g., 8% of control levels); it was not observed unless chicks were also deficient in VE. Chicks fed the Se-deficient diet supplemented with a low level of VE (2 IU/kg) failed to show hepatic GSH-T CDNB activities greater than controls. Chicks fed the Se-deficient diet had plasma GSH concentrations greater than those of Se-fed chicks, which difference was intensified by concomittant VE deficiency. These results show that GSH metabolism in the chick can be affected by nutritional status with respect to VE as well as Se. It is suggested that the increased hepatic activity of GSH-T CDNB that occurs in nutritional Se- and VE-deficiency may be a response to altered GSH metabolism rather than a compensation for loss of SeGSHpx.