Lipid metabolism in the aorta of daunomycin-induced nephrotic rats.

Several enzyme activities involved in lipid hydrolysis (acid and neutral cholesterol esterase and lipase) or synthesis (acyl-CoA synthetase, acyl-CoA: cholesterol acyltransferase and cholinephosphotransferase) were assayed in the aortas of rats with nephrosis induced by daunomycin and of rats fed on high cholesterol diet. In nephrotic rats activities of some enzymes involved in lipid hydrolysis, but not in synthesis, were increased. On the contrary, in rats fed on high cholesterol diet, the activities of all enzymes involved in lipid synthesis were significantly increased, with some increase in those involved in lipid hydrolysis. In nephrotic rats fed on high cholesterol diet all enzyme activities were markedly increased. From the view point of accumulation of cholesterol ester (CE), the ratio of hydrolysis of CE in lysosomes to CE incorporated from the blood and the ratio of hydrolysis of CE to reesterification of free cholesterol in microsomes were considered to be important. From this point of view, nephrotic hyperlipidemia was not so atherogenic as hyperlipidemia induced by the diet. The role of serum high density lipoproteins in lipid metabolism in the aorta was discussed.