Characterization of plasma lipoproteins separated and purified by agarose-column chromatography

Rudel, Lawrence L.; Lee, Jason A.; Morris, Manford D.; Felts, James M.

doi:10.1042/bj1390089

Cited by 309 publications

(72 citation statements)

References 27 publications

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“…Agarose-column chromatography was used for the separation of plasma and perfusate lipoproteins. The procedures were similar to those described by others (Rudel et al, 1974;Sheperd et al, 1975;Fainaru et al, 1977), except that ascending elution was used, which resulted in less trailing, narrower peaks and a more stable gel bed volume.…”

Section: Methodsmentioning

confidence: 96%

Relationship between activity of hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase and secretion of very-low-density-lipoprotein cholesterol by the isolated perfused liver and in the intact rat

Goh¹,

Heimberg²

1979

Biochemical Journal

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The hepatic output of triacylglycerol and cholesterol from very-low-density lipoprotein (VLD lipoprotein), and the activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase were compared in the isolated perfused rat-liver preparation and in the intact rat. The output of triacylglycerol and cholesterol from VLD lipoprotein by the perfused liver was stimulated by oleate concomitant with stimulation of hepatic microsomal hydroxymethylglutaryl-coenzyme A reductase activity. In the intact animal treated with Triton WR-1339, the magnitude of secretion of triacylglycerol and cholesterol from VLD lipoprotein coincided with the diurnal rhythm of hepatic hydroxymethylglutaryl-coenzyme A reductase activity, which was maximal at 24:00h and minimal at 12:00h. These observations suggest that the stimulation of the reductase and of the secretion of cholesterol from VLD lipoprotein by non-esterified fatty acids, as observed with the isolated perfused rat liver preparation in vitro, may also be an important physiological mechanism in vivo. Hepatic cholesterogenesis may be stimulated under conditions conducive to the secretion of the VLD lipoprotein, the primary transport form for triacylglycerol in the postabsorptive state.We have reported previously that oleate stimulated the secretion of total triacylglycerol and total cholesterol by the isolated perfused rat liver in vitro.

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Section: Methodsmentioning

confidence: 96%

Relationship between activity of hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase and secretion of very-low-density-lipoprotein cholesterol by the isolated perfused liver and in the intact rat

Goh¹,

Heimberg²

1979

Biochemical Journal

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“…Human serum (18.7 ml) was subjected to lipoprotein fractionation by ultracentrifugal flotation followed by Bio-Gel A-5m chromatography, as described by Rudel et at. (12). Three column fractions, corresponding to the reported elution positions of VLDL, LDL, and HDL, were obtained.…”

Section: Methodsmentioning

confidence: 99%

Identification of the trypanocidal factor in normal human serum: high density lipoprotein.

Rifkin¹

1978

Proc. Natl. Acad. Sci. U.S.A.

171

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The differentiation of Trypanosoma brucei from T. rhodesiense, the causative agent of human sleeping sickness, depends on their relative sensitivities to the cytotoxic effects of normal human serum. The molecule responsible for the specific lysis of T. brucei has now been isolated. Serum lipoproteins were fractionated and purified by ultracentrifugal flotation and chromatography on Bio-Gel A-5m. Trypanocidal activity was recovered in te high density lipoprotein fraction (density, 1.063-1.216 g/ml). Contamination by other serum proteins was checked by crossed immunoelectrophoresis and sodium dodecyl sulfate/acrylamide gel electrophoresis. Only a trace of fl-lipoprotein was found. The trypanocidal activity of pure human high density lipoprotein was identical to that of unfractionated serum when the following were tested: (i) time course of in vitro lysis of T. brucei; (i1) in vivo destruction of T.brucei; (iif) relative resistance of T. rhodesiense to lysis. Rat or rabbit high density lipoprotein had no trypanocidal activity.

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“…To determine whether or not LDL and methyl-LDL'were metabolically converted to other lipoproteins during the lipoprotein turnover, plasma samples (0.75-2 ml) obtained from normal and WHHL rabbits at Otime, 48 hr, and 96 hr were subjected to gel filtration by using Bio-Gel A-5m (Bio-Rad) packed in 1.5 x 90 cm glass columns (25). In each case >95% of the total plasma radioactivity eluted in a peak that corresponded with the elution position of authentic LDL and methyl-LDL, suggesting that virtually all the plasma radioactivity remained in LDL or methyl-LDL throughout the course of these studies.…”

Section: Methodsmentioning

confidence: 99%

Impaired receptor-mediated catabolism of low density lipoprotein in the WHHL rabbit, an animal model of familial hypercholesterolemia

Bilheimer

Watanabe

Kita

1982

Proc. Natl. Acad. Sci. U.S.A.

118

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The homozygous WHHL (Watanabe heritable hyperlipidemic) rabbit displays either no or only minimal low density lipoprotein (LDL) receptor activity on cultured fibroblasts and liver membranes and has therefore been proposed as an animal model for human familial hypercholesterolemia. To assess the impact of this mutation on LDL metabolism in vivo, we performed lipoprotein turnover studies in normal and WHHL rabbits using both native rabbit LDL and chemically modified LDL (i.e., methyl-LDL) that does not bind to LDL receptors. The total fractional catabolic rate (FCR) for LDL in the normal rabbit was 3.5-fold greater than in the WHHL rabbit. Sixty-seven percent of the total FCR for LDL in the normal rabbit was due to LDL receptormediated clearance and 33% was attributable to receptor-independent processes; in the WHHL rabbit, essentially all ofthe LDL was catabolized via receptor-independent processes. Despite a 17.5-fold elevated plasma pool size of LDL apoprotein (apo-LDL) in WHHL as compared to normal rabbits, the receptor-independent FCR-as judged by the turnover of methyl-LDL-was similar in the two strains. Thus, the receptor-independent catabolic processes are not influenced by the mutation affecting the LDL receptor. The WHHL rabbits also exhibited a 5.6-fold increase in the absolute rate of apo-LDL synthesis and catabolism. In absolute terms, the WHHL rabbit cleared 19-fold more apo-LDL via receptor-independent processes than did the normal rabbit and cleared virtually none by the receptor-dependent pathway. These results indicate that the homozygous WHHL rabbit shares a number of metabolic features in common with human familial hypercholesterolemia and should serve as a useful model for the study of altered lipoprotein metabolism associated with receptor abnormalities. We also noted that the in vivo metabolic behavior of human and rabbit LDL in the normal rabbit differed such that the mean total FCR for human LDL was only 64% of the mean total FCR for rabbit LDL, whereas human and rabbit methyl-LDL were cleared at identical rates. Thus, if human LDL and methyl-LDL had been used in these studies, the magnitude of both the total and receptor-dependent FCR would have been underestimated.Familial hypercholesterolemia (FH) is a human disease characterized clinically by accelerated atherosclerosis, elevated plasma levels of low density lipoprotein (LDL), xanthoma formation in tendons and skin, and inheritance as an autosomal dominant trait with a gene-dosage effect (1, 2). The defect is biochemically defined-by the absence or near-absence of LDL receptors on cells obtained from patients with the homozygous form of the disease and half the normal number of LDL receptors on the cells of heterozygotes (1, 2). One major result of diminished or absent LDL receptor activity is an impaired rate of LDL catabolism in vivo; on average, heterozygotes catabolize LDL at a fractional rate that is two-thirds of normal, whereas homozygotes catabolize LDL at a rate only one-third of normal (3). These results led to the p...

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Characterization of plasma lipoproteins separated and purified by agarose-column chromatography

Cited by 309 publications

References 27 publications

Relationship between activity of hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase and secretion of very-low-density-lipoprotein cholesterol by the isolated perfused liver and in the intact rat

Relationship between activity of hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase and secretion of very-low-density-lipoprotein cholesterol by the isolated perfused liver and in the intact rat

Identification of the trypanocidal factor in normal human serum: high density lipoprotein.

Impaired receptor-mediated catabolism of low density lipoprotein in the WHHL rabbit, an animal model of familial hypercholesterolemia

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