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.

scholarly journals The inhibition in vivo of lipoprotein lipase (clearing-factor lipase) activity by triton WR-1339

1976 ◽  
Vol 156 (3) ◽  
pp. 539-543 ◽  
Author(s):  
J Borensztajn ◽  
M S Rone ◽  
T J Kotlar
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Rat Hearts ◽  
Maximum Inhibition ◽  
Triton Wr 1339 ◽  
Perfused Rat Hearts ◽  
Hydrolysis Of ◽  
Isolated Perfused Rat Hearts

1. Lipoprotein lipase activity was measured in heart homogenates and in heparin-releasable and non-releasable fractions of isolated perfused rat hearts, after the intravenous injection of Triton WR-1339. 2. In homogenates of hearts from starved, rats, lipoprotein lipase activity was significantly inhibited (P less than 0.001) 2h after the injection of Triton. This inhibition was restricted exclusively to the heparin-releasable fraction. Maximum inhibition occurred 30 min after the injection and corresponded to about 60% of the lipoprotein lipase activity that could be released from the heart during 30 s perfusion with heparin. 3. Hearts of Triton-treated starved rats were unable to take up and utilize 14C-labelled chylomicron triacylglycerol fatty acids, even though about 40% of heparin-releasable activity remained in the hearts. 4. It is concluded that Triton selectively inhibits the functional lipoprotein lipase, i.e. the enzyme directly involved in the hydrolysis of circulating plasma triacylglycerols. 5. Lipoprotein lipase activities measured in homogenates of soleus muscle of starved rats and adipose tissue of fed rats were decreased by 25 and 39% respectively after Triton injection. It is concluded that, by analogy with the heart, these Triton-inhibitable activities correspond to the functional lipoprotein lipase.

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.

Regulation of myocardial lipoprotein lipase activity by diabetes and thyroid hormones

1994 ◽  
Vol 72 (11) ◽  
pp. 1259-1264 ◽  
Author(s):  
Limin Liu ◽  
David L. Severson
Keyword(s):  
Thyroid Hormones ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Hormone Treatment ◽  
Diabetic Rats ◽  
Lipoprotein Lipase Activity ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Perfused Hearts

Administration of streptozotocin (100 mg/kg) to adult Sprague–Dawley rats reduced both functional (heparin releasable) lipoprotein lipase activity in perfused hearts and total and heparin-releasable lipoprotein lipase activity in isolated cardio-myocytes, and produced a hypothyroid state (decreased plasma levels of triiodothyronine and thyroxine). Administration of replacement doses of triiodothyronine (3 or 10 μg/kg for 3 days) to diabetic rats normalized heparin-releasable lipoprotein lipase activity in perfused hearts, but the depressed lipoprotein lipase activity in cardiomyocytes from diabetic hearts was unchanged by in vivo thyroid hormone treatment. However, hypothyroidism in thyroidectomized rats did not alter lipoprotein lipase activity in either perfused hearts or isolated cardiomyocytes. Therefore, thyroid hormones may interact with some other factor(s) in this acute, insulin-deficient model of diabetes to selectively regulate functional, heparin-releasable lipoprotein lipase activity in perfused hearts.Key words: diabetes, hypothyroidism, lipoprotein lipase, perfused hearts, cardiomyocytes.

Epinephrine stimulates human muscle lipoprotein lipase activity in vivo

Metabolism ◽  
1999 ◽  
Vol 48 (4) ◽  
pp. 461-464 ◽  
Author(s):  
Steen B. Pedersen ◽  
Jens F. Bak ◽  
Palle Holck ◽  
Ole Schmitz ◽  
Bjørn Richelsen
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Human Muscle ◽  
Lipoprotein Lipase Activity

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
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