Chylomicrons
Mostrando 13-24 de 122 artigos, teses e dissertações.
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13. Secretion-recapture process of apolipoprotein E in hepatic uptake of chylomicron remnants in transgenic mice.
To investigate the role of apoE in hepatic uptake of chylomicron remnants, we studied chylomicron metabolism in transgenic mice overexpressing apoE in the liver. Plasma clearance of injected 125I-labeled human chylomicrons was fivefold faster in transgenic mice than in controls. Immunohistochemistry demonstrated that apoE was specifically localized at the ba
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14. Incorporation of chylomicron fatty acids into the developing rat brain.
The developing brain obtains polyunsaturated fatty acids from the circulation, but the mechanism and route of delivery of these fatty acids are undetermined. 14C-labeled chylomicrons were prepared by duodenal infusion of [1-14C]16:0, [1-14C]18:2(n-6), [1-14C]18:3(n-3), or [1-14C]22:6(n-3) into adult donor rats, and were individually injected into hepatectomi
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15. Low and high density lipoproteins and chylomicrons as regulators of rate of cholesterol synthesis in rat liver in vivo
The steady-state levels of plasma cholesterol carried in high and low density lipoproteins and in chylomicrons were varied over a wide range by use of a constant-infusion technique. After 40 hr, the rates of hepatic cholesterol synthesis and levels of hepatic cholesterol esters were measured and were related to the plasma level of each of the lipoprotein fra
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16. Chylomicrons enhance endotoxin excretion in bile.
Chylomicrons prevent endotoxin toxicity and increase endotoxin uptake by hepatocytes. As a consequence, less endotoxin is available to activate macrophages, thereby reducing tumor necrosis factor secretion. To determine whether the chylomicron-mediated increase in hepatocellular uptake of endotoxin results in increased endotoxin excretion into bile, we exami
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17. Influence of lysophosphatidylcholine on the C-apolipoprotein content of rat and human triglyceride-rich lipoproteins during triglyceride hydrolysis.
Remnants produced from rat chylomicrons in hepatectomized rats or from human chylomicrons by incubation in postheparin plasma contained much less C-apolipoproteins, but more lysophosphatidylcholine than the parent chylomicrons. A phospholipid-triglyceride emulsion absorbed C-apolipoproteins during incubation in serum, yet not in postheparin plasma, which led
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18. Normotriglyceridemic abetalipoproteinemia. absence of the B-100 apolipoprotein.
In the two genetic forms of abetalipoproteinemia described previously, recessive abetalipoproteinemia and homozygous hypobetalipoproteinemia, all lipoproteins that normally contain apolipoprotein B are absent from plasma. We describe here a new disorder in which normal low density and very low density lipoproteins are absent, but in which triglycerides are a
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19. A genetic model for absent chylomicron formation: mice producing apolipoprotein B in the liver, but not in the intestine.
The formation of chylomicrons by the intestine is important for the absorption of dietary fats and fat-soluble vitamins (e.g., retinol, alpha-tocopherol). Apo B plays an essential structural role in the formation of chylomicrons in the intestine as well as the VLDL in the liver. We have developed genetically modified mice that express apo B in the liver but
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20. Interchange of Apolipoproteins between Chylomicrons and High Density Lipoproteins during Alimentary Lipemia in Man
Apolipoproteins of the “C” group in human blood plasma, which contain the activator of the lipoprotein lipase-substrate interaction, were found to be transferred specifically from serum to phospholipid-stabilized fat emulsion. Content and distribution of apoprotein activator were measured in healthy men in the postabsorptive state and 4 h after ingestion
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21. Formation of cholesteryl ester-rich particulate lipid during metabolism of chylomicrons
The metabolism of chylomicrons doubly labeled with cholesterol-3H and triglyceride-14C was studied in unanesthetized rats which were absorbing a fatty test meal. 10 min after intravenous injection, 80% of chylomicron cholesteryl ester, but only 20% of chylomicron triglyceride, was found in the liver. Treatment of recipient rats with puromycin to block hepati
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22. Quantitation of the Transfer of Surface Phospholipid of Chylomicrons to the High Density Lipoprotein Fraction during the Catabolism of Chylomicrons in the Rat
Small chylomicrons (CM) labeled with cholesterol, cholesterol ester, phospholipid, and, in some cases, protein, were used to study the fate of these constituents as the CM are catabolized in the circulations of the hepatectomized and intact rat. In the hepatectomized animal after ½ h, CM are greatly reduced in volume, surface area, and diameter. During this
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23. Lymph Chylomicron Formation during the Inhibition of Protein Synthesis. STUDIES OF CHYLOMICRON APOPROTEINS
The effect of impaired intestinal protein synthesis on chylomicron apoprotein composition was studied in mesenteric lymph fistula rats. Lymph was obtained from animals with impaired protein synthesis given intraperitoneal acetoxycycloheximide (ACH), a potent inhibitor of protein synthesis. Lymph chylomicrons were then isolated by ultracentrifugation and puri
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24. Hepatic uptake of chylomicron remnants in WHHL rabbits: a mechanism genetically distinct from the low density lipoprotein receptor.
Homozygous Watanabe hereditary hyperlipidemic (WHHL) rabbits have a near-complete deficiency of low density lipoprotein (LDL) receptors in liver and other tissues. As a result, these rabbits clear LDL from plasma at an abnormally slow rate. In the current studies we show that WHHL rabbits clear chylomicrons from plasma at a normal rate. Chylomicrons are clea