Dibutyryl cAMP-induced Increases in triacylglycerol lipase activity in developing L8 myotube cultures

1990 ◽  
Vol 68 (6) ◽  
pp. 689-693 ◽  
Author(s):  
Warren K. Palmer ◽  
Lawrence B. Oscai ◽  
Peter J. Bechtel ◽  
Glenn A. Fisher
Keyword(s):  
Enzyme Activity ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Culture Medium ◽  
Cultured Cells ◽  
Muscle Cells ◽  
Cell Types ◽  
Dibutyryl Camp ◽  
Ph Optimum ◽  
Triacylglycerol Lipase

Triacylglycerol (TG) lipase activity, with an alkaline pH optimum, has been identified in the cellular fraction of L8 myotube cultures. This TG lipase activity was stimulated by serum and inhibited by NaCl and protamine sulfate. These characteristics have been classically described for lipoprotein lipase. It was possible to increase the activity of this TG lipase three- to fivefold by incubating the cells with dibutyryl cAMP Maximal enzyme activity was observed 16 h following the addition of 10–100 μM dibutyryl cAMP to the cultured cells. Enzyme activity returned to control levels 24 h after removal of the nucleotide from the culture medium. Serum-sensitive alkaline TG lipase activity was also identified in five other myotube preparations of cultured muscle cells. The highest levels of activity were found in rat skeletal muscle primary, H9, and L6 cell types. The finding that dibutyryl cAMP is an effective inducer of alkaline TG lipase activity provides us with a valuable model to investigate mechanisms regulating synthesis, compartmentalization, and transport of lipoprotein lipase in muscle.Key words: lipoprotein lipase, cultured muscle cells, enzyme induction.

Characterization of the triacylglycerol lipase activity in three types of rat skeletal muscle

1987 ◽  
Vol 65 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Wayne C. Miller ◽  
Warren K. Palmer ◽  
David A. Arnall ◽  
Lawrence B. Oscai
Keyword(s):  
Skeletal Muscle ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipolytic Activity ◽  
Vastus Lateralis ◽  
High Energy ◽  
Glycolytic Flux ◽  
Ph Optimum ◽  
Triacylglycerol Lipase ◽  
Triglyceride Lipase

The purpose of this study was to characterize the lipolytic activity of the alkaline triglyceride lipase in homogenates of three types of skeletal muscle obtained from heparin-perfused rat hindlimb. Specifically, the red portion of the vastus lateralis, the white portion of the vastus lateralis, and the soleus muscles were examined. To remove capillary-bound lipoprotein lipase from the capillary beds, muscle was perfused with an erythrocyte-free buffer containing 4% albumin, 5 units of heparin/mL, and 7.5 μM adenosine. Adenosine reduced perfusion pressure from 117 ± 5 to 86 ± 6 mmHg (1 mmHg = 133.32 Pa), providing evidence for an effective vasodilation. This vasodilation increased the amount of lipoprotein lipase removed from the capillary beds. By the end of the experiment, perfusates were lipoprotein lipase-free. Oxygen supply to the perfused hindlimb appeared adequate as evidenced by similar high energy phosphate values for perfused and contralateral control tissues. For example, in soleus muscle, ATP content was 4.5 ± 0.6 vs. 4.2 ± 0.3 μmol/g, ADP concentration was 1.0 ± 0.2 vs. 1.4 ± 0.2 μmol/g, and creatine phosphate level was 12.9 ± 0.7 vs. 11.0 ± 0.6 μmol/g for perfused and contralateral control soleus, respectively. In addition, K+ output by the hindlimb was negligible, while glycolytic flux of perfused muscle was similar to that measured in control tissue. The findings that triglyceride levels of soleus and red vastus lateralis were decreased suggest that endogenous triglyceride was providing energy for the hindlimb during perfusion. Skeletal muscle triglyceride lipase activity was stimulated by serum and heparin, inhibited by NaCl and protamine, and had a pH optimum of 8.1. These results are consistent with the hypothesis that the major lipolytic activity present in the intracellular compartment of skeletal muscle is the alkaline triglyceride lipase with characteristics similar to those of lipoprotein lipase.

Expression of lipoprotein lipase during differentiation of cultured L6 muscle cells

1994 ◽  
Vol 72 (3) ◽  
pp. 243-247 ◽  
Author(s):  
Mary Jo LaDu ◽  
Warren K. Palmer
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Time Course ◽  
Muscle Cells ◽  
Alkaline Ph ◽  
Ph Optimum ◽  
L6 Cells ◽  
Highly Correlated ◽  
L6 Muscle Cells

The presence of lipoprotein lipase (LPL) in L6 muscle cells is equivocal. Analysis of a 21-day time course indicates that these cells express both LPL activity and mRNA. Lipase activity peaked at 4 days after plating and decreased to a nadir at day 21 after plating. Characterization of lipase activity at 4 and 19 days after plating, corresponding to myoblasts and myotubes, respectively, indicated that most of the enzyme activity had the properties of LPL, including an alkaline pH optimum, a serum requirement, and inhibition by NaCl. LPL mRNA expression peaked at 7 days after plating and fell slightly (24%) at day 21. The primary LPL mRNA species in these cells is 3.7 kb in length. Lipase activity and LPL mRNA were highly correlated during the time course (r = +0.82), suggesting transcriptional regulation of the enzyme. These data clearly demonstrate that L6 cells express LPL during differentiation.Key words: myoblasts, myotubes, mRNA, total protein, total RNA.

scholarly journals Triacylglycerol Lipase Activities of Cultured Rat L6 Myoblasts

1985 ◽  
Vol 38 (1) ◽  
pp. 41
Author(s):  
RK Tume ◽  
F D Shaw
Keyword(s):  
Lipoprotein Lipase ◽  
Cell Lines ◽  
Lipase Activity ◽  
Maximum Velocity ◽  
Acid Lipase ◽  
Ph Optimum ◽  
Triacylglycerol Lipase ◽  
Inhibitory Component ◽  
Cell Homogenate ◽  
Hydrolysis Of

The utilization of exogenous triacylglycerol by fusing and non-fusing rat L6 myoblasts grown in culture was investigated. Although small quantities of triacylglycerol were accumulated by both cell lines during an incubation of 2 h, no evidence could be found for the presence of lipoprotein lipase, either in the cells or released into the medium. Cell homogenate studies confirmed the absence of lipoprotein lipase but revealed the presence of an acid lipase having a pH optimum at 4�6. Acid lipase activity was mainly associated with a 15 000 g pellet and was capable of hydrolysing triolein at maximum velocity in the millimolar range. Unlike lipoprotein lipase, acid lipase was strongly inhibited by serum and preliminary investigations suggest that the inhibitory component of serum is located amongst the higher density lipoproteins. It is likely that the acid lipase is of lysosomal origin and is responsible for the hydrolysis of internalized triacylglycerol for subsequent utilization by the cell.

scholarly journals Lipoprotein lipase activity of rat cardiac muscle. Changes in the enzyme activity during incubations of isolated cardiac-muscle cells in vitro

1980 ◽  
Vol 186 (3) ◽  
pp. 873-879 ◽  
Author(s):  
P Chohan ◽  
A Cryer
Keyword(s):  
Enzyme Activity ◽  
Cardiac Muscle ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Muscle Cells ◽  
Total Activity ◽  
Lipoprotein Lipase Activity ◽  
Cardiac Muscle Cells ◽  
Intracellular Enzyme

1. Isolated cardiac-muscle cells from the hearts of adult rats were shown to retain a high amount of viability during 4 h of incubation when viability was assessed by Trypan Bue stain exclusion and intracellular enzyme leakage. 2. The cells also retained their ability to take up O2 and utilize added substrates over the period of incubation at both 25 and 30 degrees C. 3. When cells from the hearts of fed rats were incubated in a buffered-salts solution at pH 7.4 in the presence of amino acids and heparin, lipoprotein lipase activity in the medium increased progressively. 4. During these incubations the intracellular activity of the enzyme remained constant and the total activity of lipoprotein lipase in the system (cells plus medium) increased by 80% over the 4 h of incubation at 25 degrees C. 5. In the absence of heparin only low amounts of enzyme activity were detectable in the medium and the total lipoprotein lipase activity in the system remained constant. 6. The measurement of lipoprotein lipase activity in either fresh homogenates of the cells or in homogenates of acetone/diethyl ether-dried powders of the cells had no effect on the overall pattern of activity change during the incubations, although as reported previously the total activity detected with acetone/diethyl either-dried preparations was approx. 3-fold higher than with fresh cell homogenates. 7. The observations were compared with published data on lipoprotein lipase activity changes in neonatal heart cell cultures maintained in vitro.

Refeeding and insulin increase lipoprotein lipase activity in rat brown adipose tissue

1989 ◽  
Vol 256 (5) ◽  
pp. E645-E650 ◽  
Author(s):  
C. M. Carneheim ◽  
S. E. Alexson
Keyword(s):  
Enzyme Activity ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Starvation Period ◽  
Lipoprotein Lipase Activity ◽  
Mrna Synthesis ◽  
Beta Adrenergic ◽  
Brown Adipose

Induction of lipoprotein lipase activity in brown adipose tissue (BAT) in response to cold stress has earlier been shown to be regulated by a beta-adrenergic mechanism and to be dependent on mRNA synthesis. In the present study, we have investigated the acute effects of refeeding after a short starvation period and the hormonal mechanism underlying the observed effects. Refeeding was found to rapidly increase tissue wet weight and lipoprotein lipase activity. The increase in enzyme activity could be blocked by the RNA synthesis inhibitor actinomycin D, indicating a gene activation. beta-Adrenergic blockade had no effect on this elevation of enzyme activity, but the increase could be mimicked by insulin injection. The results suggest that BAT contains two different pathways for regulation of lipoprotein lipase activity, both involving mRNA synthesis.

scholarly journals Substrate utilisation of cultured skeletal muscle cells in patients with CFS

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cara Tomas ◽  
Joanna L. Elson ◽  
Julia L. Newton ◽  
Mark Walker
Keyword(s):  
Skeletal Muscle ◽  
Cultured Cells ◽  
Systemic Disease ◽  
Tca Cycle ◽  
Muscle Cells ◽  
Cell Types ◽  
Chronic Fatigue ◽  
Skeletal Muscle Cells ◽  
Flux Analysis ◽  
Healthy Controls

Abstract Chronic fatigue syndrome (CFS) patients often suffer from severe muscle pain and an inability to exercise due to muscle fatigue. It has previously been shown that CFS skeletal muscle cells have lower levels of ATP and have AMP-activated protein kinase dysfunction. This study outlines experiments looking at the utilisation of different substrates by skeletal muscle cells from CFS patients (n = 9) and healthy controls (n = 11) using extracellular flux analysis. Results show that CFS skeletal muscle cells are unable to utilise glucose to the same extent as healthy control cells. CFS skeletal muscle cells were shown to oxidise galactose and fatty acids normally, indicating that the bioenergetic dysfunction lies upstream of the TCA cycle. The dysfunction in glucose oxidation is similar to what has previously been shown in blood cells from CFS patients. The consistency of cellular bioenergetic dysfunction in different cell types supports the hypothesis that CFS is a systemic disease. The retention of bioenergetic defects in cultured cells indicates that there is a genetic or epigenetic component to the disease. This is the first study to use cells derived from skeletal muscle biopsies in CFS patients and healthy controls to look at cellular bioenergetic function in whole cells.

Methylamine does not inhibit rates of endogenous lipolysis in isolated myocardial cells from rat heart

1987 ◽  
Vol 65 (2) ◽  
pp. 226-229 ◽  
Author(s):  
Albert Kryski Jr. ◽  
Terje S. Larsen ◽  
Ignasi Ramírez ◽  
David L. Severson
Keyword(s):  
Fatty Acids ◽  
Lipase Activity ◽  
Rat Heart ◽  
Diabetic Rat ◽  
Myocardial Cells ◽  
Acid Lipase ◽  
Ph Optimum ◽  
Triacylglycerol Lipase ◽  
Rat Hearts ◽  
Lysosomotropic Agent

Triacylglycerol lipase activity with a pH optimum of 5 was present in homogenates of myocardial cells from rat heart. Acid lipase activity was inhibited by serum, heparin, and increased ionic strength. Methylamine, a lysosomotropic agent, did not inhibit the basal or isoproterenol-stimulated rate of endogenous lipolysis as measured by glycerol output from control myocytes. Similarly, accelerated rates of glycerol output that are a consequence of an elevation in the intracellular stores of triacylglycerols in myocytes from diabetic rat hearts and from myocytes prepared with free fatty acids in the isolation solutions were not reduced by methylamine. Therefore, the acid lysosomal triacylglycerol lipase must not be involved in the mobilization of endogenous triacylglycerols in myocardial cells from rat heart.

scholarly journals Lipoprotein lipase activity in neonatal-rat liver cell types

1989 ◽  
Vol 259 (1) ◽  
pp. 159-166 ◽  
Author(s):  
F Burgaya ◽  
J Peinado ◽  
S Vilaró ◽  
M Llobera ◽  
I Ramírez
Keyword(s):  
Lipoprotein Lipase ◽  
Rat Liver ◽  
Lipase Activity ◽  
Cell Types ◽  
Total Activity ◽  
Time Dependent ◽  
Neonatal Rat ◽  
Lipoprotein Lipase Activity ◽  
Adult Rats ◽  
Fraction I

The lipoprotein lipase activity in the liver of neonatal (1 day old) rats was about 3 times that in the liver of adult rats. Perfusion of the neonatal liver with collagenase decreased the tissue-associated activity by 77%. When neonatal-rat liver cells were dispersed, hepatocyte-enriched (fraction I) and haemopoietic-cell-enriched (fraction II) populations were obtained. The lipoprotein lipase activity in fraction I was 7 times that in fraction II. On the basis of those activities and the proportion of both cell types in either fraction, it was estimated that hepatocytes contained most, if not all, the lipoprotein lipase activity detected in collagenase-perfused neonatal-rat livers. From those calculations it was also concluded that haemopoietic cells did not contain lipoprotein lipase activity. When the hepatocyte-enriched cell population was incubated at 25 degrees C for up to 3 h, a slow but progressive release of enzyme activity to the incubation medium was found. However, the total activity (cells + medium) did not significantly change through the incubation period. Cycloheximide produced a time-dependent decrease in the cell-associated activity. Heparin increased the amount of lipoprotein lipase activity released to the medium. Because the cell-associated activity was unchanged, heparin also produced a time-dependent increase in the total activity. In those cells incubated with heparin, cycloheximide did not affect the initial release of lipoprotein lipase activity to the medium, but blocked further release. The cell-associated activity was also decreased by the presence of cycloheximide in those cells. It is concluded that neonatal-rat hepatocytes synthesize active lipoprotein lipase.

scholarly journals The Effect of Melinjo Peel Extract in Activity of Lipoprotein Lipase Enzym of The Rats Fed a Hypercholesterolemia Diet

2018 ◽  
Vol 7 (2) ◽  
pp. 133
Author(s):  
Athira Demitri
Keyword(s):  
Enzyme Activity ◽  
Statistical Analysis ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Diet Group ◽  
Lipoprotein Lipase Activity ◽  
Oral Gavage ◽  
Hypercholesterolemic Diet ◽  
Before And After ◽  
Peel Extract

The intake of saturated fat and cholesterol that comes from food digested in the intestine resulting in free fatty acids, triglycerides, phospholipids, and cholesterol. Triglyceride levels increased can be caused by presence of impaired lipoprotein lipase (LPL) enzyme activity. LPL activity can be increased by flavonoid in plant, like Melinjo peel. The purpose of this study is to measure LPL enzyme activity before and after being given extract of Melinjo peel treatment. This research use true experimental, with study design of pretest posttest control group design. Hypercholesterolemic diet given to rats by oral gavage as much as 1,8 grams for 14 days. Melinjo peel extract were given by oral gavage for 14 days after the hypercholesterolemic diet is given. Statistical analysis used Paired Sample T-Test to compare lipoprotein lipase activity before and after treatment. Then, used MANOVA (Multivariate Analyses of Variance) to see the difference of lipoprotein lipase activity in each group after treatment.Based on statistical analysis showed that there were differences of lipoprotein lipase activity in the hypercholesterolemic diet group, HD+54.15, HD+108.30, and HD+216.60 before and after treatment significant (p. < 0.05). The activity of lipoprotein lipase in the normal diet group compared with the hypercholesterolemic and HD+216.60 group showed a significant difference (p. < 0.05). Melinjo peel extract can increased activity of lipoprotein lipase enzym after treatment, those can be due to the flavonoid in Melinjo peel extract.

Plasma Lipoprotein Lipase in Children with Idiopathic Nephrotic Syndrome

PEDIATRICS ◽  
1969 ◽  
Vol 44 (6) ◽  
pp. 1021-1024
Author(s):  
Lawrence R. Hyman ◽  
Paul W. K. Wong ◽  
Aaron Grossman
Keyword(s):  
Enzyme Activity ◽  
Nephrotic Syndrome ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Idiopathic Nephrotic Syndrome ◽  
Plasma Lipoprotein ◽  
Lipoprotein Lipase Activity ◽  
The Mean

Plasma lipoprotein lipase activity was determined in six children with idiopathic nephrotic syndrome and in six controls. The mean lipoprotein lipase activity was significantly lower in the symptomatic nephrotic patients. This decreased enzyme activity may contribute to the hyperlipemia usually observed in the nephrotic syndrome. See table in the PDF file

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