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Plasma levels and biochemical characterisation of circulating met-enkephalin in canine endotoxin shock
Abstract:
Endogenous opioid peptides have been implicated in the pathophysiology of shock (1-5). In anaesthetised mongrel dogs, administration of E coli endotoxin caused a rise in plasma met-enkephalin-like immunoreactivity (MLI). Biochemical characterisation of MLI by gel filtration chromatography revealed various molecular forms: 31K, 8K, 3-5K and the native pentapeptide in approximately equal amounts. After enzymatic treatment of column fractions the 31K form predominated (90.7%). This is the first demonstration of elevated MLI in endotoxin shock.
Insights
Endogenous opioid peptides, specifically met-enkephalin-like immunoreactivity (MLI), were found to increase during endotoxin shock in dogs. This study is the first to demonstrate elevated MLI in this critical condition.
Area of Science:
- Biochemistry
- Physiology
- Pharmacology
Background:
- Endogenous opioid peptides are linked to the pathophysiology of shock.
- Previous research suggests a role for these peptides in critical illness.
Purpose of the Study:
- To investigate the levels and molecular forms of met-enkephalin-like immunoreactivity (MLI) in endotoxin shock.
- To determine if MLI is elevated in response to E. coli endotoxin administration.
Main Methods:
- Anesthesia and administration of E. coli endotoxin to mongrel dogs.
- Measurement of plasma MLI using radioimmunoassay.
- Biochemical characterization of MLI by gel filtration chromatography and enzymatic treatment.
Main Results:
- Endotoxin administration caused a significant rise in plasma MLI.
- MLI was detected in multiple molecular forms (31K, 8K, 3-5K, pentapeptide) prior to enzymatic treatment.
- Following enzymatic treatment, the 31K form of MLI predominated, accounting for 90.7%.
Conclusions:
- This study provides the first evidence of elevated MLI in endotoxin shock.
- Endotoxin shock alters the molecular distribution of endogenous opioid peptides.