Characterization and catabolism of rat very high density lipoproteins.
نویسندگان
چکیده
A previously unrecognized lipoprotein of very high density was isolated from rat serum. During zonal ultracentrifugation of whole serum or of fractions from Sepharose 4B chromatography, a peak comigrating with a peak of cholesterol was found between the typical high density lipoproteins and the residual serum proteins. Centrifugation of chylomicrons, very low density lipoproteins, and high density lipoproteins, radio-iodinated in their lipid and protein moieties and mixed with serum, did not yield this peak. The pooled fractions contained about 85% protein. The remainder was lipid comprising cholesteryl esters, free cholesterol, triglycerides, phosphatidylcholine, and sphingomyelin. Polyacrylamide gel electrophoresis revealed bands in the region of apolipoproteins E and C as the major components. The composition suggested a lipoprotein, and this was substantiated by electron microscopy which showed particles with a mean diameter of 150 A. Their average hydrated density was 1.23 g/ml and the apparent molecular weight was 1.35 X 10(6). These very high density lipoproteins are characterized by a rapid catabolism as compared to high density lipoproteins. Within 10 min, 84% and 70% of intravenously injected 125I-labeled very high density lipoproteins were removed from plasma of male and female rats, respectively, and did not appear to be converted to lipoproteins of a different density class. Ninety-five percent of the removed 125I was recovered in the liver and the radioactivity per gram of tissue was also highest for the liver. Accordingly, the rate of clearance of 125I-labeled very high density lipoproteins was markedly reduced in functionally eviscerated rats. Radioautography revealed that most of the silver grains representing very high density lipoproteins were associated with hepatocytes and only about 1% was found over v. Kupffer cells. Uptake and degradation by freshly isolated rat hepatocytes were mediated by a saturable and specific binding site. Composition and metabolic pathway are compatible with a function of very high density lipoproteins in the transport of protein and lipids to the liver.
منابع مشابه
Characterization of the plasma lipoproteins of the genetically obese hyperlipoproteinemic Zucker fatty rat.
The plasma lipoproteins of the Zucker fatty rat were characterized with respect to lipid and apoprotein composition, and results were compared with those obtained from lean controls. Information on apoproteins was obtained from gel filtration experiments and electrophoresis on polyacrylamide gels. Very low density lipoproteins (VLDL) were increased several-fold in fatties, and 78% of their mass...
متن کاملCatabolism of human very low density lipoproteins in vitro: a fluorescent phospholipid method for monitoring lipolysis.
The catabolism of human plasma very low density lipoproteins (VLDL) by purified bovine milk lipoprotein lipase has been measured in vitro using a fluorescent phospholipid as a method to monitor lipolysis. Dansyl phosphatidylethanolamine (DPE) was incorporated into VLDL to form DPE-VLDL, and the rate of catabolism was followed by measuring the increase in fluorescence at 490 nm after the additio...
متن کاملPharmacological Action of Mentha piperita on Lipid Profile in Fructose-Fed Rats
Cardiovascular diseases with an incidence of approximately 50% are the main causes of death in most advanced countries and an increasing trend in the developing world as well. The World Health Organization estimates that 12 million people per year worldwide die from cardiovascular diseases. Cardiovascular diseases are becoming an increasing problem worldwide and hypercholesterolemia has been co...
متن کاملCorrelation of Serum Lipids and Lipoproteins with Trace Elements in Water Buffalo (Bubalus bubalis)
To evaluate the correlations of the serum concentrations of trace elements with lipids and lipoproteins in water buffalo (Bubalus bubalis), the serum concentrations of cholesterol, triglyceride, total lipids, very low density lipoproteins (VLDL-cholesterol), low density lipoproteins (LDL-cholesterol) and high density lipoproteins (HDL-cholesterol) and their correlations with serum concentration...
متن کاملLipoprotein uptake and metabolism by rat aortic smooth muscle cells in tissue culture.
Aortic smooth muscle cells from the rat were successfully grown in tissue culture and shown to have characteristic morphology. '"I-labeled homologous very low density lipoproteins and high density lipoproteins were taken up by these smooth muscle cells during incubation for 48 hours at the stationary phase. Despite multiple washings, a large proportion of the lipoprotein radioactivity associate...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of lipid research
دوره 26 6 شماره
صفحات -
تاریخ انتشار 1985