scholarly journals Intralipid administration induces a lipoprotein lipase-like activity in the livers of starved adult rats

1986 ◽  
Vol 236 (1) ◽  
pp. 273-278 ◽  
Author(s):  
S Vilaró ◽  
M Reina ◽  
I Ramírez ◽  
M Llobera
Keyword(s):  
Lipoprotein Lipase ◽  
Adult Rats ◽  
Protamine Sulphate ◽  
Triacylglycerol Lipase ◽  
Apolipoprotein C ◽  
Hepatic Triacylglycerol

The administration of Intralipid to starved adult rats induces the appearance of lipoprotein lipase (LPL)-like activity in the liver, whereas the so-called hepatic triacylglycerol lipase is unaffected. This LPL-like activity is eluted by 1.5 M-NaCl from heparin-Sepharose columns. This partially purified fraction is inhibited by 1.0 M-NaCl (91%) and by 1.0 mg of protamine sulphate/ml (79%), whereas it is stimulated 69-fold by the presence of 8.0 micrograms of apolipoprotein C-II/ml and inhibited by anti-LPL antibodies. We conclude that Intralipid administration induces the appearance of LPL activity in livers of starved adult rats. Its possible origin is discussed.

scholarly journals Effect of diabetes on acid and neutral triacylglycerol lipase and on lipoprotein lipase activities in isolated myocardial cells from rat heart

1986 ◽  
Vol 238 (1) ◽  
pp. 233-238 ◽  
Author(s):  
I Ramírez ◽  
D L Severson
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Specific Activity ◽  
Subcellular Fractions ◽  
Capillary Endothelium ◽  
Myocardial Cells ◽  
Protamine Sulphate ◽  
Triacylglycerol Lipase ◽  
Neutral Lipase ◽  
High Concentrations

A neutral triacylglycerol lipase activity that is separate and distinct from lipoprotein lipase (LPL) could be measured in homogenates of myocardial cells if protamine sulphate and high concentrations of albumin were included in the assay. This neutral lipase was predominantly particulate, with the highest relative specific activity in microsomal subcellular fractions. The induction of diabetes by the administration of streptozotocin to rats resulted in a decrease in LPL activity in myocyte homogenates and in particulate subcellular fractions, but the percentage of cellular LPL activity that was released during incubation of myocytes with heparin was normal. In contrast, neutral lipase activity was increased in diabetic myocyte homogenates and microsomal fractions. Acid triacylglycerol lipase activity was not changed in diabetic myocytes. The decrease in LPL in myocytes owing to diabetes may result in the decreased functional LPL activity at the capillary endothelium of the diabetic heart.

Modulation by phenobarbital of lipolytic activity in postheparin plasma and tissues of the rat

1982 ◽  
Vol 60 (11) ◽  
pp. 1077-1083 ◽  
Author(s):  
David M. Goldberg ◽  
M. Waheed Roomi ◽  
Alex Yu
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipolytic Activity ◽  
Sodium Dodecyl ◽  
Male Rats ◽  
Lipoprotein Lipase Activity ◽  
Protamine Sulphate ◽  
Triacylglycerol Lipase ◽  
Postheparin Lipolytic Activity

Male rats injected with phenobarbital at a dose of 100 mg/kg for 5 days manifested increased postheparin lipolytic activity of fasting plasma. Inhibition studies with protamine sulphate, 1 M NaCl, and sodium dodecyl sulphate revealed that the activities of both lipoprotein lipase and hepatic triacylglycerol lipase were increased in the postheparin plasma of the drug-treated rats. Adipose tissue lipoprotein lipase activity was also increased in the phenobarbital-treated rats. The triacylglycerol lipase activity elutable by heparin from liver slices and the residual activity of liver microsomes increased significantly in the drug-treated rats. Lipoprotein lipase of cardiac muscle and red skeletal muscle was unaltered by phenobarbital treatment. The increased postheparin lipolytic activity of fasting phenobarbital-treated rats seems to be accountable through increased lipoprotein lipase activity of adipose tissue and increased triacylglycerol lipase activity of liver, both of which may contribute to the lowered fasting concentrations of serum triacylglycerol mediated by the drug, as previously reported.

scholarly journals The storage and synthetic pools of heparin-releasable lipoprotein lipase and hepatic triacylglycerol lipase in the growing puppy

1982 ◽  
Vol 206 (3) ◽  
pp. 663-666 ◽  
Author(s):  
J B Das ◽  
I D Joshi ◽  
A I Philippart
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Marked Rise ◽  
Triacylglycerol Lipase ◽  
Endogenous Insulin ◽  
Age Related ◽  
Constant Rate ◽  
Hepatic Triacylglycerol ◽  
Insulin Secretory Response ◽  
Insulin Secretory Capacity

Age-related changes in the activities of extrahepatic lipoprotein lipase and hepatic triacylglycerol lipase were determined during a primed/constant-rate infusion of heparin for 2 h in puppies between birth and 18 weeks of age. The early (storage) and late (synthetic) phases were measured. Both phases of hepatic triacylglycerol lipase activity were well developed in the first week, reflecting the metabolic maturity of the liver at birth. During the 18 weeks of study, the activity remained relatively unchanged except for a sharp peak at 12 weeks. Extrahepatic lipoprotein lipase activity was low in the first 4 weeks of suckling. Its storage pool increased 6-fold in the next 14 weeks, with a less marked rise in its late (synthetic) pool. Sustained increases in the activity of this enzyme were first noticed during weaning, when the insulin-secretory response matured. Endogenous insulin-secretory capacity rather than the fat content of the feed appeared significant in the postnatal development of lipoprotein lipase (Clearing-factor lipase) activity.

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