scholarly journals Hydrolysis of plasma triacylglycerol-rich lipoproteins from immature and laying hens (Gallus domesticus) by lipoprotein lipase in vitro

1982 ◽  
Vol 206 (3) ◽  
pp. 647-654 ◽  
Author(s):  
H Griffin ◽  
G Grant ◽  
M Perry
Keyword(s):  
Lipoprotein Lipase ◽  
Lipid Composition ◽  
Laying Hens ◽  
Laying Hen ◽  
Dietary Lipid ◽  
Gallus Domesticus ◽  
High Density Lipoproteins ◽  
Plasma Triacylglycerol ◽  
Hydrolysis Of

Very-low-density (VLD) lipoproteins and portomicrons were isolated from the plasma of immature and laying hens and their size, lipid composition and susceptibility to hydrolysis by lipoprotein lipase were compared. In agreement with other studies, VLD lipoproteins from laying hens were found to be smaller and have a different lipid composition than VLD lipoproteins from immature hens. Portomicrons from immature and laying hens had mean diameters of about 150 nm and similar lipid compositions. Hydrolysis of VLD lipoproteins from immature hens, and portomicrons from immature and laying hens, proceeded rapidly until at least 40% of the substrate had been used. In contrast only 1-15% of laying-hen VLD-lipoprotein triacylglycerol was readily hydrolysis occurred slowly. The limited susceptibility of laying-hen VLD lipoproteins appeared to be due to their low content of lipoprotein lipase activator apoprotein, which occurred despite an abundance of activator in the high-density lipoproteins of laying-hen plasma. The results provide further evidence that the liver of the laying hen synthesizes specialized lipoproteins. Their limited susceptibility to hydrolysis by lipoprotein lipase is probably a major factor in ensuring transport of lipid to yolk rather than to other tissues. The form of transport of dietary lipid, however, is similar in immature and laying hens.

Heparin-released lipolytic and esterolytic activities of human and rabbit plasmas

1961 ◽  
Vol 201 (5) ◽  
pp. 915-922 ◽  
Author(s):  
B. Shore ◽  
V. Shore
Keyword(s):  
Fatty Acids ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Ethyl Esters ◽  
Lipoprotein Lipase Activity ◽  
Hydrolysis Of

The enzymes released into both human and rabbit plasmas by heparin injection hydrolyzed, in addition to triglyceride moieties of lipoproteins, a number of mono- and diglycerides of C16 and C18 fatty acids after in vitro addition of the unemulsified glycerides to the plasma. In human postheparin plasma, these enzymes also hydrolyzed glycerides of butyric and caproic acids. The pure triglycerides and methyl or ethyl esters of C16 and C18 fatty acids were not substrates. The heparin-released activities for the hydrolysis of glycerides added in vitro persisted after all activity for the lipolysis of lipoproteins had been destroyed by heat. These activities also differed from lipoprotein lipase activity with respect to the effects of 1 m NaCl, dialysis, and aging the plasma at 4 C. It appears that heparin releases into the blood more than one enzyme or more than one form of an enzyme which may be involved in a stepwise degradation to fatty acids and glycerol of the triglyceride moieties of lipoproteins of density less than 1.007 g/ml.

DIETARY LIPIDS, INFECTION AND MACROPHAGE PROCOAGULANT ACTIVITY

1987 ◽  
Author(s):  
M C E van Dam-Mieras ◽  
A D Muller ◽  
G Hornstra
Keyword(s):  
Lipid Composition ◽  
Cell Types ◽  
Dietary Lipid ◽  
Infection Process ◽  
Dietary Lipids ◽  
Procoagulant Activity ◽  
Morphological Evidence ◽  
Blood Monocytes ◽  
Peripheral Blood Monocytes

It is generally accepted that the type of dietary fat influences arterial thrombosis and atherosclerosis. Although it is still largely unknown how the dietary lipid composition influences the process of atherogenesis, it is evident that several cell types are involved. Morphological evidence for the involvement of monocyte/macropages has been given.We described before that the dietary lipid composition has striking effects on the procoagulant activity of macrophages. When macrophages were isolated from the spleens of healthy rats the procoagulant activity slightly decreased during the first few hours after isolation, and reached a plateau value after 4 hours. When, however, macrophages were obtained from animals infected with a pneumona virus (PVM) different results were obtained:Experiments carried out with peripheral blood monocytes showed close resemblance to those described in the table.These results show that:- moncytes/macrophages isolated from PVM-infected animals increase their procoagulant activity during in vitro culture- the differences in macrophage procoagulant activity found in cells obtained from healthy animals fed diets containing different lipids no longer were found in PVM-infected animalsThis would implicate that the infection process has a more profound influence on macrophage procoagulant activity that the composition of the diet

Preferential in vivo accumulation of sn-2,3-diacylglycerols in postheparin plasma of rats

1977 ◽  
Vol 55 (10) ◽  
pp. 1075-1081 ◽  
Author(s):  
N. Morley ◽  
A. Kuksis ◽  
A. G. D. Hoffman ◽  
G. Kakis
Keyword(s):  
Portal Vein ◽  
Lipoprotein Lipase ◽  
Hepatic Lipase ◽  
Water Interface ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Oil Water ◽  
Hydrolysis Of

The stereochemical course of in vivo hydrolysis of triacylglycerols by lipoprotein lipase was investigated by determining the structure of diacylglycerol intermediates in postheparin plasma of rats which had been fed [3H]glycerol-labeled Intralipid 2 h before an injection of heparin or had been given an injection of a mixture of [3H]glycerol-Intralipid and heparin. During the clearance of both the natural chylomicrons and the artificial emulsion, sn-2,3-diacylglycerols (60–80%) were found to be the dominant enantiomers. Similar results were obtained when the contribution of the hepatic lipase was altered, either by tying off the mesentery artery and portal vein before injection of heparin, or by injection of heparin directly into the portal vein. These findings are consistent with a preferential release of the acyl group from the sn-1 position of the triacylglycerol molecule as demonstrated previously in vitro. A preferential orientation of the substrate in the enzyme–substrate complex or at the oil–water interface is discussed as a possible basis for these effects.

scholarly journals Effects of C apoproteins on the activity of endothelium-bound lipoprotein lipase

1978 ◽  
Vol 175 (3) ◽  
pp. 1143-1146 ◽  
Author(s):  
T W Lukens ◽  
J Borensztajn
Keyword(s):  
Lipoprotein Lipase ◽  
Rat Heart ◽  
Perfused Rat Heart ◽  
Hydrolysis Of

Rat apoprotein C-II activated the hydrolysis of triacylglycerol in apoprotein-depleted chylomicrons by lipoprotein lipase in vitro and in the perfused rat heart. Apoproteins C-I and C-III-3 inhibited the hydrolysis of the triacylglycerol moiety in intact and apoprotein C-II-re-activated chylomicrons in vitro, but had no effect on the hydrolysis in situ.

scholarly journals The effect in vitro of high-density lipoprotein on hydrolysis of triacylglycerol by lipoprotein lipase

1981 ◽  
Vol 200 (2) ◽  
pp. 453-456 ◽  
Author(s):  
M P Rogers ◽  
I Hutchinson
Keyword(s):  
Adipose Tissue ◽  
High Density Lipoprotein ◽  
Lipoprotein Lipase ◽  
Bovine Milk ◽  
Density Lipoprotein ◽  
High Density ◽  
Rat Adipose Tissue ◽  
Adipose Tissue Lipoprotein Lipase ◽  
Hydrolysis Of

In an incubation system in vitro with fully activated Intralipid as substrate, rat high-density lipoprotein inhibits the hydrolysis of triacylglycerol by lipoprotein lipase from rat adipose tissue, but does not inhibit hydrolysis by the enzyme from bovine milk. The pattern of inhibition suggests that substrate and high-density lipoprotein may compete for association with rat adipose-tissue lipoprotein lipase.

THE IN VITRO UPTAKE OF TRITIATED OESTRADIOL BY THE OVIDUCT OF IMMATURE AND LAYING CHICKENS

1970 ◽  
Vol 63 (2) ◽  
pp. 265-274
Author(s):  
Helene C. Cecil ◽  
J. Bitman ◽  
C. S. Shaffner
Keyword(s):  
Laying Hens ◽  
Laying Hen ◽  
Incubation Mixture ◽  
Body Tissues ◽  
Endogenous Oestrogen ◽  
In Vitro Uptake

ABSTRACT The oviduct of the immature chick had a special affinity for oestradiol during in vitro incubation with tritiated oestradiol. All anatomical portions of the oviduct concentrated 3-6 times more radioactivity than other body tissues. When the immature birds were pretreated with nonlabelled oestradiol, the ability of the ovary, liver and muscle to concentrate 3H-oestradiol was unaffected. In contrast, accumulation of radioactivity by oviducts from pretreated birds was reduced to a level comparable to other body tissues. The oviducts from nonlaying hens were able to accumulate more oestradiol per unit of weight than the oviducts from laying hens. Presumably the laying hen had a source of endogenous oestrogen which reduced the ability of the oviduct to accumulate 3H-oestradiol from the incubation mixture.

scholarly journals Action of liproprotein lipase on apoprotein-depleted chylomicrons

1978 ◽  
Vol 175 (1) ◽  
pp. 53-61 ◽  
Author(s):  
T W Lukens ◽  
J Borensztajn
Keyword(s):  
Lipoprotein Lipase ◽  
Physiological Role ◽  
Rat Plasma ◽  
High Density Lipoproteins ◽  
Complete Restoration ◽  
Immobilized Trypsin ◽  
Plasma High Density ◽  
First Time

1. Rat lymph chylomicrons were exposed to soluble and to immobilized trypsin. This treatment caused no detectable changes in the chylomicron structure or lipid composition, but did result in virtually total depletion of all their tetramethylurea-soluble apoproteins. 2. The capacity of these apoprotein-depleted chylomicrons to act as substrate for lipoprotein lipase in vitro and in situ (i.e. isolated perfused rat heart) was decreased by about 90 and 75% respectively, compared with intact chylomicrons. 3. On incubation with rat plasma high-density lipoproteins, trypsin-treated chylomicrons readily acquired a full apoprotein complement. This resulted in the complete restoration of their capacity to act as substrate for lipoprotein lipase both in vitro and in situ. 4. It is suggested that with the use of try,sin-treated chylomicrons it is now possible for the first time to investigate the physiological role that individual apoproteins play in the catabolism of triacylglycerol-rich lipoproteins by lipoprotein lipase.

scholarly journals INHIBITION OF LIPOPROTEIN LIPASE ACTIVITY FOLLOWING INJECTION OF PITUITARY EXTRACTS INTO RABBITS

1960 ◽  
Vol 112 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Aaron Kellner ◽  
Robert L. Hirsch ◽  
Elizabeth B. Freeman
Keyword(s):  
Lipoprotein Lipase ◽  
Anterior Pituitary ◽  
Human Beings ◽  
Lipoprotein Lipase Activity ◽  
Anatomical Changes ◽  
Alkaline Extract ◽  
Pituitary Glands ◽  
Human Anterior Pituitary ◽  
Hydrolysis Of

Rabbits given a single subcutaneous injection of an alkaline extract of hog, bovine, or human anterior pituitary glands developed marked hyperlipemia within 12 to 24 hours. The injections in some instances were followed by sickening and death of the animal, though no anatomical changes responsible for these consequences could be determined. No such sequelae were observed in animals given much larger injections of comparable extracts made from other tissues. An inhibitor to lipoprotein lipase appeared regularly in the serum of the injected animals in association with the hyperlipemia. The injection of heparin into such animals failed to result in the elaboration of clearing factor, and serum from these animals inhibited in vitro the hydrolysis of lipid emulsions by active lipoprotein lipase obtained from normal rabbits or human beings. The inhibitor was produced only in vitro by the pituitary extracts. It did not antagonize the anticoagulant action of heparin, and is probably a lipoprotein.

scholarly journals Hydrolysis of chylomicron triacylglycerol by endothelium-bound lipoprotein lipase. Effect of decreased apoprotein C-II/C-III ratio

1979 ◽  
Vol 183 (1) ◽  
pp. 171-174 ◽  
Author(s):  
T J Kotlar ◽  
J Borensztajn
Keyword(s):  
Lipoprotein Lipase ◽  
Perfused Heart ◽  
Hydrolysis Of

Chylomicrons with a decreased ratio of C-II/C-III apoproteins on their surface produced by the addition of apoproteins C-III-0 or C-III-3 to intact rat lymph chylomicrons. These chylomicrons inhibited the activity of soluble lipoprotein lipase in vitro, but had no effect on the activity of the endothelium-bound enzyme in the perfused heart.

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