[Experimental study of glucosylated low density lipoprotein metabolism and atherosclerosis]

The effect of LDL glucosylation on its pathway was assessed. Human serum LDL was isolated by density gradient ultracentrifugation and its purity was identified by polyacrylamide gel electrophoresis. LDL was radioiodinated with 125I by iodine monochloride. LDL radioreceptor assay was performed and intracellular total cholesterol was determined in cultured human fibroblasts. Maximal binding affinity (Bmax) of LDL receptor was 47 ng LDL/mg cell protein, Km was 9.4 micrograms/ml. The receptor mediated binding, internalization and degradation of glucosylated LDL were significantly decreased compared with control LDL, but total cholesterol content of cultured fibroblasts incubated with glucosylated LDL was significantly higher than those incubated with control LDL. The results suggested that glucosylation of LDL might be an important mechanism for the high incidence of disturbed lipid metabolism and atherosclerosis in diabetic patients.