Low Density Lipoprotein (LDL) Receptor Activity is Modulated by Soybean (Glycine max) Globulins in Cell Culture

Planta Medica ◽  
1992 ◽  
Vol 58 (S 1) ◽  
pp. 580-581
Author(s):  
M. Lovati
1992 ◽  
Vol 122 (10) ◽  
pp. 1971-1978 ◽  
Author(s):  
Maria R. Lovati ◽  
Cristina Manzoni ◽  
Alberto Corsini ◽  
Agnese Granata ◽  
Roberta Frattini ◽  
...  

1992 ◽  
Vol 285 (2) ◽  
pp. 641-646 ◽  
Author(s):  
P N M Demacker ◽  
P J van Heijst ◽  
A F H Stalenhoef

We studied the metabolism of chylomicrons in homozygous Watanabe heritable hyperlipidaemic (WHHL) rabbits and in cholesterol-fed or normally fed New Zealand White (NZW) rabbits by measuring the concentrations of apoprotein B-48 and of retinyl palmitate in their serum after feeding fat plus this vitamin according to two different protocols. Compared with NZW controls, retinyl palmitate accumulated in both hyperlipidaemic groups under study, not only in the d less than 1.019 fraction but also in the low-density lipoprotein (LDL) fraction. A strong correlation was found between the retinyl palmitate concentration in either the d less than 1.019 fraction or the LDL fraction of the WHHL rabbits and the concentrations of cholesterol and triacylglycerols in these fractions. This suggests that retinyl palmitate is exchanged rapidly between exogenous and endogenous lipoproteins. This is supported by the lack of a correlation between the retinyl palmitate concentrations and the intensity of the apoprotein B-48 band in the respective d less than 1.019 fractions or LDL fractions; in most fractions, in which large amounts of retinyl palmitate were present, the intensity of the apoprotein B-48 band was not increased compared with the fasting concentrations. Assuming that retinyl palmitate is a marker for the transfer of exogenous lipids, the results of our experiments indicate that the removal of exogenous lipids is delayed by complexing to endogenously synthesized lipoproteins. However, the clearance of apoprotein B-48 is normal and thus independent of the LDL-receptor activity.


1984 ◽  
Vol 68 (1) ◽  
pp. 183-194
Author(s):  
A.M. Leichtner ◽  
M. Krieger

Low density lipoprotein (LDL) was chemically modified by the addition of omega-(6-phospho)-tetra(alpha 1–3)mannosyl-(alpha 1–2)mannose (M56P), a phosphorylated oligosaccharide containing a terminal mannose 6-phosphate residue. Uptake and degradation of this modified LDL (M56P-LDL) by Chinese hamster ovary (CHO) cells occurred via the lysosomal enzyme (mannose 6-phosphate) receptor pathway. Cellular processing of M56P-LDL was saturable, specific for the mannose 6-phosphate marker, and occurred with approximately threefold higher affinity than that of native LDL by the LDL receptor pathway. Mannose 6-phosphate receptor activity, as measured by degradation of M56P-LDL, was ninefold lower than the LDL receptor activity. Degradation of M56P-LDL was more sensitive to inhibition by the lysosomotropic agent chloroquine than was degradation of LDL, suggesting differences in the intracellular processing of mannose 6-phosphate-bearing ligands and LDL. Previously isolated CHO cell lines defective in LDL receptor activity resembled parental CHO cells in their ability to process M56P-LDL. The potential use of M56P-LDL in the isolation of cells with pleiotropic mutations affecting receptor-mediated endocytosis is discussed.


1982 ◽  
Vol 62 (4) ◽  
pp. 397-401 ◽  
Author(s):  
M. Weight ◽  
C. Cortese ◽  
U. Sule N. E. Miller ◽  
B. Lewis

1. The concordance of low density lipoprotein (LDL) receptor activity of blood mononuclear cells was examined in 26 pairs of monozygotic and 17 pairs of dizygotic normolipidaemic young adult male twins. 2. Receptor activity was quantified as the degradation of 125I-labelled LDL during a 6 h incubation, after derepression of the cells for 72 h in lipoprotein-deficient medium. 3. The total variance of receptor activity was similar in the two groups of twins. In contrast, within-pair variance was five times greater in dizygotic twins than in monozygotic twins (P < 0.001). 4. Estimates of heritability, mostly based on the intra-class correlation coefficients (monozygotic, r = 0.83; dizygotic, r = 0.39), ranged from 0.72 to 1.05. 5. These results suggest that the maximal LDL receptor activity of peripheral cells in normolipidaemic subjects is largely genetically determined.


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