期刊名称：Journal of Clinical Biochemistry and Nutrition
印刷版ISSN：0912-0009
电子版ISSN：1880-5086
出版年度：1988
卷号：4
期号：1
页码：41-47
DOI：10.3164/jcbn.4.41
出版社：The Society for Free Radical Research Japan
摘要：Since lipid peroxides (LPO) possess cytotoxic characteristics, a study of the influence that oxidized low density lipoprotein (LDL) has on insulin receptors was performed by employing human cultured lymphocytes (IM-9 cells). The oxidized LDL was produced by ultraviolet irradiation, and a 5-min irradiation resulted in an LPO concentration reaching 2.6 times that of the preirradiated value. The insulin binding for each concentration of oxidized LDL was as follows: the control (before ultraviolet irradiation) was 7.0±0.46% (mean±SE); while 2-min irradiated LDL gave 6.7±0.70%; 5-min irradiated, 4.9±0.69%; 10-min, 4.0±0.17%; 20-min, 4.5±0.24%. That is, a significant decrease in insulin binding was observed following treatment with LDL irradiated for 5, 10, or 20min ( p <0.05, p <0.01, p <0.01, respectively). Scatchard analysis indicated that such a drop in insulin binding was not caused by any decrease in the number of receptors, but by a decrease in affinity. Preincubation of the cells with vitamin E showed an inhibitory trend against these decreases; furthermore, this drop in insulin binding was found to be irreversible when cells that had been incubated for 24h with fetal bovine serum-free, oxidized LDL had been washed and incubated for another 24h prior to binding assay. The above evidence suggests that the oxidized LDL acts directly on the membrane of IM-9 cells and causes a drop in the affinity of the insulin receptors.
