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.

scholarly journals The lipoprotein lipase (clearing-factor lipase) activity of cells isolated from rat cardiac muscle

1978 ◽  
Vol 174 (2) ◽  
pp. 663-666 ◽  
Author(s):  
P Chohan ◽  
A Cryer
Keyword(s):  
Cardiac Muscle ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Cell Type ◽  
Cardiac Muscle Cells ◽  
Adult Rat ◽  
Rat Hearts ◽  
Major Cell Type ◽  
Total Lipoprotein

The total lipoprotein lipase activity recovered in suspension of cells prepared from adult rat hearts was unaffected by the nutritional state of the animals used. The enzyme activity present in the cell suspensions was almost exclusively associated with the cardiac muscle cells present as the major cell type.

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.

Microwave Radiation Effects on Cardiac Muscle Cells in Vitro

1981 ◽  
Vol 86 (2) ◽  
pp. 358 ◽  
Author(s):  
M. J. Galvin ◽  
C. A. Hall ◽  
D. I. McRee
Keyword(s):  
Cardiac Muscle ◽  
Microwave Radiation ◽  
Radiation Effects ◽  
Muscle Cells ◽  
Cardiac Muscle Cells

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.

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.

Effects of carbon monoxide on cardiac muscle cells in culture

1988 ◽  
Vol 255 (3) ◽  
pp. C291-C296 ◽  
Author(s):  
A. C. Nag ◽  
K. C. Chen ◽  
M. Cheng
Keyword(s):  
Growth Rate ◽  
Cardiac Muscle ◽  
Structural Organization ◽  
Optimal Growth ◽  
Muscle Cells ◽  
Cellular Growth ◽  
Cardiac Muscle Cells ◽  
Cells In Culture ◽  
Significant Difference

Embryonic rat cardiac muscle cells grown in the presence of various tensions of CO (5-95%) without the presence of O2 survived and exhibited reduced cell growth, which was concentration dependent. When cardiac muscle cells were grown in the presence of a mixture of CO (10-20%) and O2 (10-20%), the growth rate of these cells was comparable to that of the control cells. Cardiac myocytes continued to beat when exposed to varying tensions of CO, except in the case of 95% CO. The cells exposed to different concentrations of CO contained fewer myofibrils of different stages of differentiation compared with the control and the culture exposed to a mixture of 20% O2 and 20% CO, with cells that contained abundant, highly differentiated myofibrils. There was no significant difference in the structural organization of mitochondria between the control and the surviving experimental cells. It is evident from the present studies that O2 is required for the optimum in vitro cellular growth of cardiac muscle. Furthermore, CO in combination with O2 at a concentration of 10 or 20% can produce optimal growth of cardiac muscle cells in culture.

Proopiomelanocorticotropin (POMC) peptides and lipoprotein lipase activity in vitro

Peptides ◽  
1995 ◽  
Vol 16 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Peter Eichhorn ◽  
Peter Schwandt ◽  
Werner O. Richter
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity

scholarly journals Lipoprotein Lipase Activity and mRNA Are Up-Regulated by Refeeding in Adipose Tissue and Cardiac Muscle of Sheep

2000 ◽  
Vol 130 (4) ◽  
pp. 749-756 ◽  
Author(s):  
Muriel Bonnet ◽  
Christine Leroux ◽  
Yannick Faulconnier ◽  
Jean-François Hocquette ◽  
François Bocquier ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Cardiac Muscle ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity
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