EFFECT OF LIPID PEROXIDES ON PROSTACYCLIN AND THROMBOXANE GENERATION IN HYPERCHOLESTEROLEMIC RABBITS

Rabbits feeding on atherogenic diet for 60 days resulted in high level of plasma lipid peroxides as well as extreme hypercholesterolemia. Both of them kept at high level until 35 days after atherogenic diet stopped. At the same time, as compared with the control group, plasma PGI₂ level was remarkably decreased while TXA₂ and platelet aggregability were increased. Atherosclerotic vessel walls contain high levels of lipid peroxides associated with decreased PGI₂ and increased TXA₂ generation. Atherosclerotic plaques had the highest level of lipid peroxides and TXA₂ while PGI production was the least, as compared with non-plaque tissue of the same artery and the normal arteries. The condition of normal arteries was just reverse. It was concluded that the concurrent presence of lipid peroxidation products may be seriously considered when evaluating the hyperlipidemia as a cause of atherosclerosis, and the elevation of TXA₂ generation in arteries might be taken into consideration when evaluating an imbalance of PGI₂/TXA₂ in plasma.