scholarly journals Effect of protamine on lipoprotein lipase and hepatic lipase in rats

1994 ◽  
Vol 304 (3) ◽  
pp. 959-966 ◽  
Author(s):  
M Hultin ◽  
G Olivecrona ◽  
T Olivecrona
Keyword(s):  
Endothelial Cell ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Binding Sites ◽  
Hepatic Lipase ◽  
Lipoprotein Lipase Activity ◽  
Cell Surfaces ◽  
Intravenous Injections

The polycation protamine impedes the catabolism of triglyceride-rich lipoproteins and this has been suggested to be due to intravascular inactivation of lipoprotein lipase. We have made intravenous injections of protamine to rats and found that both lipoprotein lipase and hepatic lipase activities were released to plasma. The effect of protamine was more short-lived than that obtained by injection of heparin. The release of hepatic lipase by protamine was as effective as the release by heparin, while the amount of lipoprotein lipase released by protamine was only about one-tenth of that released by heparin. This was not due to inactivation of lipoprotein lipase, since injection of an excess of heparin 10 min after injection of protamine released as much lipoprotein lipase activity to plasma as in controls. The results in vivo differed from those obtained in model experiments in vitro. Protamine was able to almost quantitatively release both lipoprotein lipase and hepatic lipase from columns of heparin-agarose. The displacement was dependent on the total amount of protamine that had passed over the column, indicating that it was due to occupation by protamine of all available binding sites. Our results in vivo showed that the binding sites for lipoprotein lipase were not blocked as efficiently as those for hepatic lipase, indicating that the binding structures were not identical. It was concluded that the impaired turnover of lipoproteins by protamine probably was due to prevention of binding of the lipoproteins to endothelial cell surfaces rather than to impaired lipase function.

Effect of titanium on lipoprotein lipase activity in vivo and in vitro

2010 ◽  
Vol 24 (2) ◽  
pp. 95-98 ◽  
Author(s):  
Alireza Ani ◽  
Mohsen Ani ◽  
Ali-A. Moshtaghie ◽  
Hassan Ahmadvand
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity

A discrepancy between in vivo and in vitro lipoprotein lipase activity in a patient with Tangier disease

1991 ◽  
Vol 203 (1) ◽  
pp. 97-99 ◽  
Author(s):  
Akira Takizawa ◽  
Tsugikazu Komoda ◽  
Shigeru Hokari ◽  
Yoshikatsu Sakagishi ◽  
Akira Tanaka
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Tangier Disease

scholarly journals Effects of insulin, glucocorticoids and adrenaline on the activity of rat adipose-tissue lipoprotein lipase

1980 ◽  
Vol 188 (1) ◽  
pp. 185-192 ◽  
Author(s):  
P Ashby ◽  
D S Robinson
Keyword(s):  
Protein Synthesis ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Fat Bodies ◽  
Rat Adipose Tissue ◽  
Adipose Tissue Lipoprotein Lipase

The lipoprotein lipase activity of epididymal fat-bodies from starved rats was measured during incubations at 37 degrees C in vitro. Protein synthesis independent activation of the enzyme, previously observed during incubations at 25 decrease C, also occurs at 37 degrees C. Protein-synthesis-dependent increases in the activity of the enzyme occur in the presence of insulin and are markedly potentiated by glucocorticoids. The effects on the activity of the enzyme of insulin alone, or in the presence of glucocorticoids, are correlated with its effects on total protein synthesis in the tissue. Adrenaline antagonizes the increase in activity of the enzyme brought about by insulin and abolishes the potentiation of insulin action by glucocorticoids. These changes may be due, at least in part, to its stimulation of inactivation of the enzyme in the tissue. It is suggested that changes in adipose-tissue lipoprotein lipase activity that occur with changes in nutritional status in vivo result from the combined effects of changes in plasma insulin and glucocorticoid concentrations.

scholarly journals Post-translational regulation of lipoprotein lipase activity in adipose tissue

1978 ◽  
Vol 176 (3) ◽  
pp. 865-872 ◽  
Author(s):  
P Ashby ◽  
D P Bennett ◽  
I M Spencer ◽  
D S Robinson
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Translational Regulation ◽  
Progressive Increase ◽  
Lipoprotein Lipase Activity ◽  
Dependent Part ◽  
Adipose Tissue Lipoprotein Lipase ◽  
Energy Dependent

Changes in adipose-tissue lipoprotein lipase activity that are independent of protein synthesis were investigated in an incubation system in vitro. Under appropriate conditions at 25 degrees C a progressive increase in the enzyme activity occurs that is energy-dependent. Part of the enzyme is rapidly inactivated when the tissue is incubated with adrenaline or adrenaline plus theophylline. The mechanism of this inactivation appears to be distinct from, and to follow, the activation of the enzyme. A hypothesis is presented to account for the results in terms of an activation of the enzyme during obligatory post-translational processing and a catecholamine-regulated inactivation of the enzyme as an alternative to secretion from the adipocyte.

Lipoprotein lipase-suppressing mediator in serum of endotoxin-treated rats

1986 ◽  
Vol 251 (4) ◽  
pp. E470-E476 ◽  
Author(s):  
G. J. Bagby ◽  
C. B. Corll ◽  
J. J. Thompson ◽  
L. A. Wilson
Keyword(s):  
Lipoprotein Lipase ◽  
Exposure Time ◽  
Lipase Activity ◽  
Significant Suppression ◽  
Lipoprotein Lipase Activity ◽  
Activity Maximum ◽  
A Cell

The conditions under which lipoprotein lipase-suppressing mediator is present in serum of endotoxin-treated rats was determined in this study. The suppression of lipoprotein lipase activity in 3T3-L1 cells was used as a bioassay for mediator in serum. Endotoxin (0.1-10 micrograms/ml) and serum from control rats did not suppress lipoprotein lipase activity. Maximum suppression of cell lipoprotein lipase activity (70%) by serum from endotoxic rats required a cell exposure time of 5 h. At the highest dose of endotoxin used (1 mg/100 g), significant suppression was achieved when cells were incubated with 0.5% serum from endotoxic rats (P less than 0.05). Serum obtained 2-3 h after endotoxin injection possessed the maximal ability to suppress lipase activity, but suppressing activity was not present in serum collected 8 h after endotoxin. Rats rendered tolerant to endotoxin by 5 daily injections (0.1 mg/100 g) did not contain detectable levels of mediator in serum after endotoxin injection. The results demonstrate that the presence of lipoprotein lipase activity-suppressing mediator is transitory after in vivo exposure of naive rats to endotoxin, but does not appear in serum of endotoxin tolerant rats.

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.

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