Induction of Hypozincemia and Hepatic Metallothionein Synthesis in Hypersensitivity Reactions.
Abstract
Recent evidence indicates that hypersensitivity reactions, produced in rats by the administration of a protein antigen, alters plasma zinc and iron homeostasis by depressing concentrations of these trace minerals. Studies were performed to determine if hypozincemia occurs as a consequence of redistribution of zinc from plasma to liver by a mechanism involving enhanced hepatic metallothionein (MT) synthesis. MT, a high cystein-containing cytoplasmic protein, possesses a high affinity for zinc and other heavy metals and has been implicated in zinc homeostasis. Antigen challenge (0.5 mg BSA) in rate previously sensitized with either 5 or 10 mg BSA produced a significant decrease in plasma zinc and iron concentrations within 7 hr in an apparent dose-dependent manner. Plasma zinc depression was accompanied by an increase in hepatic MT content as well as MT-associated total Zn and 65 Zn used to pulse-label the metalloprotein. The depression in plasma zinc, but not iron, and the enhanced synthesis of MT was significantly reduced by prior treatment of rats with actinomycin D. This finding suggests a requirement for new mRNA synthesis for zinc, but not iron alterations during hypersensitivity reactions. Results support the concept that induction of hepatic MT may be a common mechanism involved in altered plasma zinc homeostasis regardless of the initiating pathophysiologic condition. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 19, 1978
- Accession Number
- ADA056538
Entities
People
- E. C. Hauer
- F. A. Beall
- P. Z. Sobocinski
- W. J. Canterbury Jr.
Organizations
- United States Army Medical Research Institute of Infectious Diseases