Lipoprotein lipase and uptake of triacylglycerol, cholesterol and phosphatidylcholine from chylomicrons by mammary and adipose tissue of lactating rats in vivo

Scow, Robert O.; Chernick, Sidney S.; Fleck, TR

doi:10.1016/0005-2760(77)90006-6

Cited by 79 publications

(33 citation statements)

References 48 publications

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“…Dietary TVA is not incorporated into CE, due to low specificity of lecithin:cholesterol acyl transferase (LCAT) for this fatty acid 9/11CLA may be selectively incorporated into plasma PL and TG for rapid utilization by tissues. This selectivity may be important during lactation when an increase in mammary gland lipoprotein lipase (LPL) activity in rodents [13] is accompanied by extensive hydrolysis and uptake of fatty acids from plasma TG and PL by the mammary gland for milk fat synthesis [34]. Data from the present study indicated that 78% of total TVA and 82% of total 9/11CLA in blood plasma were found in PL plus TG, and these fractions contained 64% of total fatty acids in plasma.…”

Section: Fatty Acid Profiles In Liver and Carcass Of Suckling Pupsmentioning

confidence: 60%

“…Data from the present study indicated that 78% of total TVA and 82% of total 9/11CLA in blood plasma were found in PL plus TG, and these fractions contained 64% of total fatty acids in plasma. Rat mammary gland LPL removes fatty acids esterified in the sn-1 position of plasma TG and PL prior to removal of fatty acids at the sn-3 position of the TG [34]. Trans11-18:1 is preferentially concentrated in the sn-1 position of plasma TG [9] and PL [10].…”

Section: Fatty Acid Profiles In Liver and Carcass Of Suckling Pupsmentioning

confidence: 99%

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Dietary trans-vaccenic acid (trans11-18:1) increases concentration of cis9,trans11-conjugated linoleic acid (rumenic acid) in tissues of lactating mice and suckling pups

2002

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-Lactating mice were fed trans-vaccenic acid (trans11-18:1, TVA) to assess desaturation of TVA to cis9,trans11-conjugated linoleic acid (9/11CLA). Diets contained 30 g . kg -1 18:2n-6 (LA) or 20 g LA plus 10 g 18:0 (SA), TVA, or a CLA mixture (MCLA). Compared with SA, feeding TVA increased 9/11CLA concentrations in blood plasma phospholipid, triglyceride, and free fatty acid fractions. However, concentrations of 9/11CLA in plasma fractions were greater when MCLA was fed compared with SA or TVA. No 9/11CLA was detected in liver of mice fed SA, and it was only 1 mg . g -1 of total fatty acids in the carcass. In contrast, 9/11CLA content of liver (5 mg . g -1 ) and carcass (6 mg . g -1 ) of mice fed TVA was similar to liver (5 mg . g -1 ) and carcass (7 mg . g -1 ) of mice fed MCLA. Mammary tissue of SA-fed mice had no detectable 9/11CLA, compared with 5 or 14 mg . g -1 for TVA or MCLA-fed mice. Stearoyl-CoA desaturase activity in mammary tissue from TVA-fed dams was 14% greater compared with SA. Activity of this enzyme in liver tissue was similar among treatments. In pups nursing TVA-fed dams, 9/11CLA accounted for 3 mg . g -1 in liver but no 9/11CLA was detected in the carcass. In pups nursing MCLA-fed dams, however, 9/11CLA accounted for 8 and 6 mg . g -1 in liver and carcass. Results indicated TVA desaturation enhanced 9/11CLA in tissues and milk fat. stearoyl-CoA desaturase / trans-vaccenic acid / rumenic acid / milk fatRésumé -L'acide trans-vaccénique (trans11-18:1) alimentaire augmente la concentration de l'acide linoléique conjugué (acide ruménique, cis9, t rans11-18:2) dans les tissus de la souris allaitante et du souriceau. Des souris allaitantes ont reçu de l'acide trans-vaccénique (trans11-18:1, TVA) afin de démontrer la désaturation du TVA en acide linoléique conjugué cis9,trans11-18:2 (9/11CLA). Des régimes contenant 30 g . kg -1 d'acide linoléique (18:2n-6, LA) ou 20 g de LA plus Reprod. Nutr. Dev. 42 (2002) 85-99 85

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Section: Fatty Acid Profiles In Liver and Carcass Of Suckling Pupsmentioning

confidence: 60%

Section: Fatty Acid Profiles In Liver and Carcass Of Suckling Pupsmentioning

confidence: 99%

Dietary trans-vaccenic acid (trans11-18:1) increases concentration of cis9,trans11-conjugated linoleic acid (rumenic acid) in tissues of lactating mice and suckling pups

2002

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“…At the onset of lac tation, adipose tissue LPL levels drop significantly while mam mary gland LPL levels increase significantly (McBride and Korn 1963;Hamosh et al 1970;Ramirez et al 1983). Previous studies on small laboratory animals that were killed suggested mam mary LPL activity is correlated with lipid uptake by the mam mary gland (Scow et al 1977). Higher levels of LPL could increase the rate of lipid uptake by the mammary gland and increase the rate of milk synthesis relative to the females' own maintenance metabolism.…”

Section: Physiological and Biochemical Zoologymentioning

confidence: 99%

Physiology and Behavior Influence Lactation Efficiency in Northern Elephant Seals (Mirounga angustirostris)

McDonald

Crocker

2006

Physiological and Biochemical Zoology

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The efficiency with which mothers convert acquired energy into milk is a key determinant of the magnitude of parental in vestment in mammals; however, the mech~isms underlying lactation efficiency are poorly understood. Investigations on northern elephant seals have shown lactation efficiency, mea sured as the proportion of total energy expenditure that goes to the pup as milk, increases with age. In a cross-sectional study the physiological and behavioral determinants of lactation ef ficiency were investigated in eight young and seven prime (older) elephant seals by conducting behavioral observations and collecting milk, blood, and tissue on days 3 and 22 of lactation. Milk composition, circulating fatty acid and triglyc eride concentrations, and mammary and blubber lipoprotein lipase activity were determined. Prime females had significantly greater percent milk fat and circulating fatty acids on day 3 than did young females, but these differences disappeared by day 22. The ability for prime females to produce higher-energy milk early in lactation may allow them to increase lactation efficiency by increasing the rate of energy transfer. In addition, prime females spent significantly more time resting. A com bination of reduced activity and more rapid energy delivery likely explains the increase in lactation efficiency with age found in a previous study.

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“…Some return to the blood as FFAs ( 4 ), and there is evidence that this is a large fraction of the fatty acids from the chylomicrons. When chylomicrons were perfused through rat adipose and mammary tissue, respectively, 45 and 35% of the fatty acids were released to the medium as FFAs ( 28 ). After a fat meal, in humans there is a large change in composition of plasma FFAs, suggesting that many of the fatty acids come from lipolysis of chylomicrons ( 29 ).…”

Section: Discussionmentioning

confidence: 99%

The tissue distribution of lipoprotein lipase determines where chylomicrons bind

Savonen

Hiden

Hultin

et al. 2015

Journal of Lipid Research

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This article is available online at http://www.jlr.org regulated in a tissue-specifi c manner ( 1, 2 ). As an example, the activity in adipose tissue is relatively low between meals but rises postprandially ( 6 ). This has been suggested to govern when and to what extent lipids are delivered to the adipose tissue for storage ( 1, 2 ). On the other hand, it has been argued that the only role of the enzyme is to release the fatty acids in a form that can be transferred from lipoproteins into cells or onto albumin, and that the amount taken up by individual cells is usually governed by transport processes ( 7 ) and/or the metabolic balance within the cell ( 8 ) rather than by the rate at which the lipase releases fatty acids at endothelial sites adjacent to the cell.The first step in chylomicron catabolism is that the lipoprotein particles bind to the endothelial surface, a process named margination. Goulbourne et al. ( 9 ) have demonstrated that the margination requires LPL bound to GPIHBP1. Defi ciency of GPIHBP1, genetic or in mouse models, leads to equally severe hyperchylomicronemia as defi ciency of LPL itself ( 10 ). In this setting normal amounts of LPL are produced, but do not reach the endothelial surface. Mouse genetic models with altered expression of LPL have been generated. Total LPL defi ciency due to gene knockout leads to lethal hypertriglyceridemia within 18 h of life ( 11 ). By mating heterozygous LPL knockout mice with transgenic mice that express human LPL in either muscle ( 12 ) or heart ( 13 ), mouse lines have been generated that express the enzyme in only a single tissue. Here we have taken advantage of these mouse models to study to what extent the expression of LPL in a tissue governs initial binding and/or deposition of lipids in that tissue . For this we used rat chylomicrons, labeled in vivo with [3 H]-retinol (which is incorporated into retinyl esters and serves as label for the core lipids and for the chylomicron particles) and [ ]retinol (primarily in ester form, providing a tracer for the core lipids) were injected. TG label was cleared more rapidly than core label. There were no differences between the mouse lines in the rate at which core label was cleared. Two minutes after injection, about 5% of the core label, and hence chylomicron particles, were in the heart of WT mice. In mice that expressed LPL only in skeletal muscle, and had much reduced levels of LPL in the heart, binding of chylomicrons was reduced to 1%, whereas in mice that expressed LPL only in the heart, the binding was increased to over 10%. The same patterns of distribution were evident at 20 min when most of the label had been cleared. Thus, the amount of LPL expressed in muscle and heart governed both the binding of chylomicron particles and the assimilation of chylomicron lipids in the tissue.

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Lipoprotein lipase and uptake of triacylglycerol, cholesterol and phosphatidylcholine from chylomicrons by mammary and adipose tissue of lactating rats in vivo

Cited by 79 publications

References 48 publications

Dietary trans-vaccenic acid (trans11-18:1) increases concentration of cis9,trans11-conjugated linoleic acid (rumenic acid) in tissues of lactating mice and suckling pups

Dietary trans-vaccenic acid (trans11-18:1) increases concentration of cis9,trans11-conjugated linoleic acid (rumenic acid) in tissues of lactating mice and suckling pups

Physiology and Behavior Influence Lactation Efficiency in Northern Elephant Seals (Mirounga angustirostris)

The tissue distribution of lipoprotein lipase determines where chylomicrons bind

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