scholarly journals Rapid effects of isoprenaline, glucagon, pacing and potassium arrest on post-heparin lipoprotein lipase activity in the perfused rat heart

1979 ◽  
Vol 182 (1) ◽  
pp. 253-255 ◽  
Author(s):  
J Simpson
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Rat Heart ◽  
Lipoprotein Lipase Activity ◽  
Perfusion Medium ◽  
Perfused Rat Heart ◽  
Rat Hearts ◽  
Isolated Rat

The amount of lipoprotein lipase activity released by heparin into the perfusion medium of isolated rat hearts could be increased within 60s by isoprenaline, glucagon or pacing. Potassium arrest and propranolol inhibited the effects of isoprenaline and pacing respectively.

Metabolic fate of rat heart endothelial lipoprotein lipase

1988 ◽  
Vol 255 (3) ◽  
pp. E247-E254 ◽  
Author(s):  
T. Chajek-Shaul ◽  
G. Bengtsson-Olivecrona ◽  
J. Peterson ◽  
T. Olivecrona
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Rat Heart ◽  
Metabolic Fate ◽  
Low Concentrations ◽  
Rat Hearts ◽  
Catalytically Active ◽  
Isolated Rat

When isolated rat hearts were perfused with medium containing 125I-labeled bovine lipoprotein lipase (LPL), they bound both lipase activity and radioactivity. More than 80% of the bound lipase could be rapidly released by heparin. Low concentrations of bovine LPL displaced 50-60% of the endogeneous, endothelial-bound LPL. Higher concentrations caused additional binding. Both binding and exchange were rapid processes. The hearts continuously released endogenous LPL into the medium. An antiserum that inhibited bovine but not rat LPL was used to differentiate endogeneous and exogeneous LPL activity. When the pool of endothelial LPL was labeled with bovine 125I-labeled LPL and then chased with unlabeled bovine LPL, approximately 50% of the labeled lipase was rapidly displaced. During chase perfusion with medium only, catalytically active bovine LPL appeared in the perfusate. The rate of release was similar to that observed for endogeneous LPL activity and amounted to 10-13% of the heparin-releasable fraction in the first 5 min of perfusion. There was little or no degradation of bovine 125I-labeled LPL to fragments or acid-soluble products. These results indicate that endothelial LPL is accessible for exchange with exogeneous LPL and that detachment rather than degradation may be the pathway for catabolism of endothelial LPL.

scholarly journals Differences in the metabolism of very-low-density lipoproteins by isolated beating-heart cells and the isolated perfused rat heart. Evidence for collagenase-released extracellular lipoprotein lipase

1980 ◽  
Vol 186 (2) ◽  
pp. 431-438 ◽  
Author(s):  
O V Rajaram ◽  
M G Clark ◽  
P J Barter
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Rat Heart ◽  
Beating Heart ◽  
Low Density Lipoproteins ◽  
Heart Cells ◽  
Low Density ◽  
Lipoprotein Lipase Activity ◽  
Very Low Density Lipoproteins ◽  
Perfused Rat Heart

1. The metabolism of VLD lipoproteins (very-low-density lipoproteins) was studied in intact isolated beating-heart cells and isolated perfused rat heart from starved animals by using [14C]triacylglycerol fatty acid-labelled VLD lipoprotein prepared from rats previously injected with [1-14C]palmitate. 2. 14C-labelled VLD lipoprotein was metabolized by the isolated perfused heart, but was only minimally metabolized by the heart cells unless an exogenous source of lipoprotein lipase was added. 3. Measurements of lipoprotein lipase at pH 7.4 with the natural substrate 14C-labelled VLD lipoprotein indicated that during collagenase perfusion of the heart the enzyme was released into the perfusate, the activity released being proportional to the concentration of collagenase used. Lipoprotein lipase activity in homogenates of hearts that had been perfused with collagenase showed a corresponding loss of activity. 4. At high perfusate concentrations of collagenase, inactivation of the released lipoprotein lipase occurred. 5. Lipoprotein lipase activity was largely undetectable in the homogenate of the isolated heart cells. 6. It is concluded that the lipoprotein lipase responsible for the hydrolysis of VLD lipoprotein triacylglycerol is predominantly located externally to the heart muscle cells and that its release can be facilitated by perfusion of the heart with bacterial collagenase.

scholarly journals Increase in Lipoprotein Lipase Activity in Isolated Rat Adipose Tissue by Selenate.

1993 ◽  
Vol 16 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Hiroshi UEKI ◽  
Yusuke OHKURA ◽  
Toshio MOTOYASHIKI ◽  
Nobuaki TOMINAGA ◽  
Tetsuo MORITA
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Rat Adipose Tissue ◽  
Isolated Rat

Lipoprotein lipase activity in rat heart myocytes

Life Sciences ◽  
1977 ◽  
Vol 21 (3) ◽  
pp. 467-473 ◽  
Author(s):  
Gregory J. Bagby ◽  
Maw-Shung Liu ◽  
Judy A. Spitzer
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Rat Heart ◽  
Lipoprotein Lipase Activity ◽  
Rat Heart Myocytes

Effect of Glucocorticoids on Lipoprotein Lipase Activity in Rat Heart and Adipose Tissue

1975 ◽  
Vol 7 (02) ◽  
pp. 152-157 ◽  
Author(s):  
P. de Gasquet ◽  
E. Pequignot-Planche ◽  
N. Tonnu ◽  
F. Diaby
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Rat Heart ◽  
Lipoprotein Lipase Activity

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.

Increasing effect of vanadate on lipoprotein lipase activity in isolated rat fat pads

1990 ◽  
Vol 279 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Misaki Sera ◽  
Katsuhiro Tanaka ◽  
Tetsuo Morita ◽  
Hiroshi Ueki
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Fat Pads ◽  
Isolated Rat
Sign in / Sign up

Export Citation Format

Share Document