Lipoprotein receptor activity of peritoneal macrophages from insulin-deficient mice

Abstract

Binding, uptake and degradation of¹²⁵I-labeled normal very low density lipoprotein(¹²⁵I-n-VLDL) from normal swine plasma and¹²⁵I-labeled β-migrating VLDL (¹²⁵I-β-VLDL) from hypercholesterolemic rabbit plasma by peritoneal macrophages of mice rendered insulin-deficient by streptozotocin (250 mg/kg) were studied. It was found that the amount of binding, uptake and degradation of¹²⁵I-n-VLDL by macrophages from the diabetic mice was 2-fold or 2.5-fold higher than by macrophages from normal mice, resulting from an increase in the binding capacity of VLDL receptors on the macrophages from the insulin-deficient rodents. In contrast, the binding, uptake and degradation of¹²⁵I-β-VLDL by macrophages from diabetic mice were reduced to only about 45 % of normal levels because of a decrease in the number and affinity of the receptors for β-VLDL. These experimental results indicate that n-VLDL is more important than β-VLDL in the pathogenes is of atherosclerosis in insulin-dependent diabetes.

Keywords

lipoprotein receptor / very low density lipoprotein (VLDL) / insulin-deficient / macrophages

References

[1] FengZC, et al.. The receptor-mediated accumulation of triglyceride in macrophages exposed to very low density lipoproteins. Acta Acad Med Wuhan, 1983, 3(1): 8-8

[2] BatesSR, et al.. Very low density lipoproteins promote triglyceride accumulation in macrophages. Arteriosclerosis, 1984, 4: 103-103

[3] GoldsteinJL, et al.. Cholesteryl ester accumulation in marophages resulting from receptor-mediated uptake and degradation of hypercholesterolemic canine ß-very low density lipoproteins. J Biol Chem, 1980, 255: 1839-1839

[4] MahleyRW, et al.. Cholesteryl ester synthesis in macrophages: stimulated by very low density lipoproteins from cholesterol fed animals of several species. J Biol Chem, 1980, 21: 970-970

[5] RudermanNB, et al.. Diabetes as an atherogenic factor. Progress in Cardiovascular Diseases, 1984, 26: 373-373

[6] KraemerFB, et al.. Effect of noninsulin-dependent diabetes mellitus on the uptake of very low density lipoproteins by thioglycolate elicited mouse peritoneal macrophages. J Clin Endocrinol Metab, 1985, 61: 342-342

[7] ChengG, et al.. Metabolism of n-VLDL and ß-VLDL in peritoneal macrophages from diabetic mice. J Tongji Med Univ, 1989, 9: 53-53

[8] MacFarlaneAS, et al.. Efficient tracelabeling of proteins with iodine. Nature, 1958, 182: 53-53

[9] LowryOH, et al.. Protein measurement with Fol in phenol reagent. J Biol Chem, 1951, 193: 265-265

[10] St. ClairRW, et al.. Metabolism by cells in culture of low-density lipoproteins of abnormal compositon from nonhuman primates with diet-induced hypercholesterolemia. Biochim Biophys Acta, 1980, 618: 63-63

[11] DengYZ, et al.. Relationship of VLDL receptor and LPL in metabolism of VLDL by macrophages. J Tongji Med Univ, 1991, 11(1): 39-39

[12] HowardBV. Lipoprotein metabolism in diabetes. J Lipid Res, 1987, 28: 613-613