Particulate Fat in Lymph and Blood

Dole, Vincent P.; Hamlin, James T.

doi:10.1152/physrev.1962.42.4.674

Cited by 285 publications

(58 citation statements)

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“…This suggests that the increased transport of lipid in the lymph was due to an increase in the number, rather than size, of chylomicrons (see Yokoyama and Zilversmit 1965). It would appear that chylomicrons from the cow contain higher percentages of phospholipid, cholesterol ester, free cholesterol, and protein than those from monogastric animals (Dole and Hamlin 1962). However, the possibility that variation in the preparation of the washed chylomicrons may have caused these differences in composition cannot be overlooked.…”

Section: Discussionmentioning

confidence: 99%

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The Effect of Oil-Feeding and Starvation on the Composition and Output of Lipid in Thoracic Duct Lymph in the Lactating Cow

Hartmann¹,

Harris²,

Lascelles³

1966

Aust. Jnl. Of Bio. Sci.

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Section: Discussionmentioning

confidence: 99%

“…Phospholipid was determined on dried extracts (ethanol-ether, 3 : 1 v/v) of plasma by the method of Zilversmit and Davis (1950). Glucose was determined by the glucose oxidase method of Huggett and Nixon (1957) and free fatty acid by the method of Dole (1956).…”

Section: (F) Analytical Determinationsmentioning

confidence: 99%

The Effect of Oil-Feeding and Starvation on the Composition and Output of Lipid in Thoracic Duct Lymph in the Lactating Cow

Hartmann¹,

Harris²,

Lascelles³

1966

Aust. Jnl. Of Bio. Sci.

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“…The chylomicrons were combined and used for column chromatography. VLDL were isolated by serial centrifugations (34).…”

Section: Methodsmentioning

confidence: 99%

Liver Fatty Acid-binding Protein Initiates Budding of Pre-chylomicron Transport Vesicles from Intestinal Endoplasmic Reticulum

Neeli

Siddiqi

Mahan³

et al. 2007

Journal of Biological Chemistry

105

102

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The rate-limiting step in the transit of absorbed dietary fat across the enterocyte is the generation of the pre-chylomicron transport vesicle (PCTV) from the endoplasmic reticulum (ER). This vesicle does not require coatomer-II (COPII) proteins for budding from the ER membrane and contains vesicle-associated membrane protein 7, found in intestinal ER, which is a unique intracellular location for this SNARE protein. We wished to identify the protein(s) responsible for budding this vesicle from ER membranes in the absence of the requirement for COPII proteins. We chromatographed rat intestinal cytosol on Sephacryl S-100 and found that PCTV budding activity appeared in the low molecular weight fractions. Additional chromatographic steps produced a single major and several minor bands on SDS-PAGE. By tandem mass spectroscopy, the bands contained both liver and intestinal fatty acid-binding proteins (L-and I-FABP) as well as four other proteins. Recombinant proteins for each of the six proteins identified were tested for PCTV budding activity; only L-FABP and I-FABP (23% the activity of L-FABP) were active. The vesicles generated by L-FABP were sealed, contained apolipoproteins B48 and AIV, were of the same size as PCTV on Sepharose CL-6B, and by electron microscopy, excluded calnexin and calreticulin but did not fuse with cis-Golgi nor did L-FABP generate COPII-dependent vesicles. Gene-disrupted L-FABP mouse cytosol had 60% the activity of wild type mouse cytosol. We conclude that L-FABP can select cargo for and bud PCTV from intestinal ER membranes.During intestinal lipolysis of a fat-containing meal, 2 mol of fatty acid (FA) 4 are produced for every mole of triacylglycerol (TAG) hydrolyzed. These FA and the remaining sn-2-monoacylglycerol are absorbed across the enterocyte apical plasma membrane. Absorption of the FA is thought to occur, at least in part, via specific membrane proteins. FATP4, which is highly expressed at the apical surface of the enterocyte, was shown to increase FA uptake following overexpression, and antisense oligonucleotide knockdown of FATP4 expression reduced FA uptake (1). FABPpm, which was first identified in jejunal microvillus membranes, may also be involved in FA uptake, as anti-FABPpm antibodies have been found to inhibit uptake (2-4). CD36 has been shown to be important for FA uptake into muscle and adipose tissues (5, 6) and may also play a role in intestinal FA transport (7). 5 CD36 is also important for intestinal TAG synthesis and subsequent TAG export from the intestine (8). Kinetic experiments have shown that in addition to protein-mediated transport, a diffusional mechanism for FA uptake by the enterocyte exists as well (9).Once inside the intestinal absorptive cell, the FA are largely bound to intracellular fatty acid-binding proteins (FABP), and the majority are rapidly converted into TAG (10) for subsequent export from the cell as the major component of intestinal lipoproteins, chylomicrons, and very low density lipoproteins.The absorptive enterocyte contains high levels...

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“…The resuspended chylomicrons were then separated into fractions containing chylomicrons with Sf values of 400-1000, 1000-2000 and> 2000 by centrifugation according to the method of Fraser (1970) which was based on a nomogram designed from physical principles by Dole and Hamlin (1962).…”

Section: Preparative Ultracentrifugationmentioning

confidence: 99%

Size of Lipoproteins in Intestinal Lymph of Sheep and Suckling Lambs

Gooden¹,

Fraser²,

Bosanquet³

et al. 1979

Aust. Jnl. Of Bio. Sci.

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The relative importance of chylomicrons (Sf> 400) and very low density lipoproteins in transporting lipids in lymph was investigated in surgically prepared adult sheep and pre-ruminant lambs fed low fat diets or infused intraduodenally with corn oil. The concentration of triacylglycerol in the intestinal lymph of sheep and lambs was increased from 520 and 925 mg/1oo ml to 2326 and 2367 mg/loo ml respectively when corn oil was infused into the duodenum and the ratio of triacylglycerol to phospholipid changed from 3 ·7 and 5 . 5 to 9·5 and 9·7 respectively. The flow of lymph also increased. Electron microscopy and analytical and preparative ultracentrifugation showed that lymph lipoproteins from sheep and lambs fed low fat diets consisted mainly of lipoproteins 50 nm in diameter and that very low density lipoproteins (Sf 20-400) contributed up to 75 % of the Sf > 20 lipoproteins. There were no lipoproteins with diameters above 150 nm.Infusion of corn oil into the duodenum of sheep and lambs increased the diameters of lymph lipoproteins. Most were 80--100 nm in diameter but substantial numbers above 150 and up to 400 nm were observed. The maximum contribution of very low density lipoproteins to lipoproteins of Sf> 20 was 27-30%.The above findings demonstrate that the size of intestinal lymph lipoprotein particles increases with the amount of lipid absorbed from the small intestines and that the transport of lymph lipids, in ruminants, is similar to that previously found in rats, rabbits and man.

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Particulate Fat in Lymph and Blood

Cited by 285 publications

References 0 publications

The Effect of Oil-Feeding and Starvation on the Composition and Output of Lipid in Thoracic Duct Lymph in the Lactating Cow

The Effect of Oil-Feeding and Starvation on the Composition and Output of Lipid in Thoracic Duct Lymph in the Lactating Cow

Liver Fatty Acid-binding Protein Initiates Budding of Pre-chylomicron Transport Vesicles from Intestinal Endoplasmic Reticulum

Size of Lipoproteins in Intestinal Lymph of Sheep and Suckling Lambs

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