Attenuation by prostacyclin of adrenaline-stimulated lipid peroxidation in the myocardium

The study aimed to investigate the effect of adrenaline upon lipid peroxidation processes in the myocardium and to evaluate the effect of prostacyclin upon the content of lipid peroxidation products in adrenaline-treated hearts. Anaesthetized rabbits were infused for 2 hours with adrenaline /1 microgram/kg/min/, adrenaline and prostacyclin /2 ng/kg/min/ and prostacyclin alone; controls received saline. After termination of infusion lipid peroxidation products /conjugated double bonds CDB, malondialdehyde MDA, lipid-soluble fluorescent material, FM/ and SH groups were measured in the myocardial tissue. Adrenaline significantly increased the content of all three indices of lipid peroxidation and decreased the concentration of soluble SH groups. PGI2 infused simultaneously significantly decreased the concentration of final metabolites of peroxidation /MDA, FM/ and prevented decrease of SH groups. The content of intermediate products of peroxidation, CDB was elevated. In conclusion, enhanced free radical activity, resulting in increased peroxidation of myocardial lipids may contribute to known injurious effect of adrenaline upon myocardium. The finding that PGI2 prevents increased formation of final peroxidation products gives support for the hypothesis that anti-free radical activity may be a component of cytoprotective action of prostacyclin.