Effect of Cortisone on Lipid Metabolism of Plasma, Liver and Aorta and on Retrogression of Atherosclerosis in the Rabbit

Abstract

This study was made to assess the relative metabolic effects of cortisone in rabbits on a normal or high cholesterol diet. Cortisone was administered daily for 14 days to normal and atherosclerotic rabbits. Determinations were made of lipid distribution and phospholipid metabolism of plasma, liver and aorta of these groups compared with that of untreated, normal and cholesterol-fed animals. Aortas were examined and judged for severity of atherosclerosis. The most notable effects of administered cortisone on lipid distribution were the extent of mobilized neutral fat to the liver and the elevated level in the plasma. Cholesterol metabolism appeared to be differently affected by cortisone administration to animals on the two types of diet; in cholesterol-fed rabbits the plasma ester cholesterol was significantly depressed while in normal animals cortisone appeared to have promoted a hypercholesterolemia. Plasma lipid interrelationships of cholesterol-fed, cortisone injected rabbits were more like normal and different from that of untreated, atherosclerotic rabbits. The radioactivity data showed that plasma phospholipid turnover rate was increased while specific activity of aortic phospholipid was decreased in rabbits administered cortisone compared with that of the untreated groups. The Sf 12–400 classes of serum lipoproteins were increased in amount in normal and cholesterol-fed rabbits subsequent to administered cortisone. The metabolic findings are discussed with regard to their association with a marked degree of retrogression of the severity of atherosclerosis observed in the cortisone-treated rabbits.