Modulated Responses to Restraint Stress and Inflammation in Metallothionein-Null Mice

Abstract

The present study was designed to investigate the effects of restraint stress and inflammation on levels of serum zinc and corticosterone in metallothionein-null (MT^-/-) mice with respect to a modulating role of MT in stress responses. In wild-type (MT^+/+) mice, serum zinc concentration decreased after injection of lipopolysaccharide (LPS), but increased with exposure to restraint. In LPS-treated mice, serum zinc levels were higher in MT^-/- mice than in MT^+/+ mice. On the other hand, after exposure to restraint stress, serum corticosterone levels increased in both mice, but the increase rate was higher in MT^+/+ mice than in MT^-/- mice. In addition, injection of LPS decreased serum corticosterone in MT^+/+ mice, but there was no change in MT^-/- mice. These findings suggest that MT may modify the zinc metabolism and stress responses in inflammatory and restraint stress.