Ferric iron potentiates cell depolarization by a circulating shock protein.

Abstract

OBJECTIVE:

To determine whether or nor iron affects the depolarizing activity of a circulating shock protein that appears in plasma after hemorrhage.

DESIGN:

Randomized design.

SETTING:

University laboratory.

ANIMALS:

Healthy male Sprague-Dawley rats weighing 300 to 400 g with femoral artery and vein cannulas placed 4 days before hemorrhage.

INTERVENTION:

A 20-mL/kg hemorrhage and plasma collection.

MAIN OUTCOME MEASURES:

Depolarizing activity was measured as the increased fluorescence of an oxonol dye in the presence of Fe3+, Fe2+, or the iron chelator deferoxamine mesylate and was titrated against increasing concentrations of circulating shock protein or iron. Circulating shock protein was derived from plasma and was purified in two steps: stepwise ammonium sulfate precipitation followed by denaturing ion-exchange chromatography and refolding.

RESULTS:

At physiologic concentrations, Fe3+ but not Fe2+ potentiated the depolarizing activity of plasma after ammonium sulfate. Addition of deferoxamine abolished activity. Denaturing chromatography removed nearly all the depolarizing activity; however, Fe3+ restored activity to this fraction. Fe3+ increased total activity and decreased the concentration at which 50% activity was observed.

CONCLUSION:

These data indicate that physiologic concentrations of Fe3+ may act to modulate the depolarizing activity of circulating shock protein that in turn mediates the intracellular accumulation of salt and water in shock.

• Authors: B J Eastridge, J A Evans, D N Darlington, D S Gann
• Journal: Archives of surgery (Chicago, Ill. : 1960) (Arch Surg) Vol. 129 Issue 3 Pg. 245-51 (Mar 1994) ISSN: 0004-0010 [Print] United States
• PMID: 8129597 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Ferric Compounds
• Ferrous Compounds
• Flavoproteins
• Heat-Shock Proteins
• Pyridoxal Phosphate
• Deferoxamine

Topics

• Animals
• Deferoxamine (pharmacology)
• Dose-Response Relationship, Drug
• Electrophysiology
• Erythrocyte Membrane (drug effects)
• Ferric Compounds (pharmacology)
• Ferrous Compounds (pharmacology)
• Flavoproteins (pharmacology)
• Heat-Shock Proteins (blood, drug effects, physiology)
• Hemorrhage (blood)
• Male
• Pyridoxal Phosphate (pharmacology)
• Random Allocation
• Rats
• Rats, Sprague-Dawley