Non-protein SH Groups Research Articles

Regulation of thiols in the brain. I. Concentrations of thiols and glutathione reductase activity in different parts of the rat brain during hypoxia.

Abstract The effects of mild hypoxia on the concentrations of non-protein and protein thiol (SH) groups and on glutathione reductase activity in' the cerebral grey matter, cerebellum and brain stem of rats were studied. In normoxic rats the protein and non-protein SH levels were similar in the three parts studied except that the nonprotein SH level was much lower in the brain stem. In the cerebellum the glutathione reductase activity was higher than the activities in the cerebral grey matter and brain stem, which were equal. Hypoxia for I h markedly decreased the glutathione reductase activity and the SH levels in the parts studied, which implied an increase in the level of oxidized glutathione. After 2·5 h the amounts of protein and non-protein SH groups increased to the control value despite the fact that the glutathione reductase activity was still low. This suggested that hypoxia changes the role of glutathione reductase in the regulation of SH levels and in consequence the mechanism of that regulation. The dynamics of the changes observed under hypoxia were different in the three parts of the rat brain. Hypoxia made these parts change in a different way from that observed in normoxic rats. Changes of protein paralleled the non-protein SH changes during hypoxia.