Central functions of glutathione, and peptides and amino acids related to glutathione synthesis and metabolism, on stress responses

Glutathione reductase irreversibly catalyzes the reduction from oxidized glutathione to reduced glutathione.Both oxidized glutathione and reduced glutathionedose-dependently decreased distress vocalizations and induced sleep-like behavior in chicks under acute stressful conditions. Energy expenditure was rapidly decreased by intracerebroventricular injection of reduced glutathione, but thenincreased gradually.This change in energy expenditure was correlated with behavioral changes in whichreduced glutathione induced hypnotic and sedative effects shortly after injection, followed by a period where activity increased. There are three types of dipeptides related to reduced glutathione, i.e., glutamyl-cysteine, cysteinyl-glycine and glutamyl-glycine that are theoretically present in tissues.These peptides also attenuated distress vocalizations and spontaneous activity induced by social isolationand did not vary in their action from each other.Reduced glutathione is a tripeptide which consists of L-glutamate, L-cysteine and glycine. All three amino acids induced sedative and hypnotic effects.In conclusion, glutathione and its constituents are helpful to ameliorating an acute stressful condition.