Thiol compounds as protective agents in erythrocytes under oxidative stress.

The potential for the thiol-containing drugs, N-acetyl cysteine and N-mercaptopropionyl glycine, to act as antioxidants intracellularly has been studied in erythrocytes under oxidative stress. The effects have been compared with that of the glutathione peroxidase inhibitor, mercaptosuccinate. The results show differential responses of sickle and normal erythrocytes to the thiol compounds. N-acetyl cysteine is the more efficacious with no toxic effects in these systems. N-Mercaptopropionyl glycine is not only limited in its ability to demonstrate antioxidant capacity in erythrocytes but also exerts deleterious effects.