scholarly journals Relationship between type L hormone-sensitive lipase activity and endogenous triacylglycerol in the hearts of colchicine-treated rats

1984 ◽  
Vol 224 (3) ◽  
pp. 793-798 ◽  
Author(s):  
W C Miller ◽  
W K Palmer ◽  
L B Oscai
Keyword(s):  
Enzyme Activity ◽  
Cyclic Amp ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Negative Relationship ◽  
Indirect Evidence ◽  
Colchicine Treatment ◽  
Hormone Sensitive Lipase ◽  
Control Value ◽  
Hormone Sensitive

Colchicine injection was used as a tool to potentiate the increase in intracellular lipoprotein lipase (type L hormone-sensitive lipase) activity normally seen with fasting to determine if elevation of enzyme activity by this method produced a reduction in endogenous triacylglycerol (TG) in rat heart. Both fasting and fasting+colchicine treatment increased total lipoprotein lipase (LPL) activity from a control value of 80 units/g to approx. 144 units/g. The initial control value was obtained at 08:00 h after overnight feeding and the final values were obtained at 17:00 h, after 9 h of fasting. Fasting alone increased activity in both the capillary-bound LPL and type L hormone-sensitive lipase (HSL) fractions of cardiac muscle. In contrast, colchicine treatment, by blocking the export of enzyme from the cell as a result of microtubular disruption, restricted the increase in enzyme activity to the intracellular fraction of the heart. There was a highly significant (P less than 0.001) negative relationship (r = −0.73) between type L HSL activity and TG content in hearts of fasting and fasting+colchicine-treated rats. At a time when type L HSL activity was increased and TG content decreased, the cyclic AMP concentration of heart remained unchanged, ruling out the possibility that cyclic AMP might be activating any one of the identified cardiac TG lipases. These data provided indirect evidence that type L HSL is ‘seeing the intracellular TG droplet’ and that this enzyme may play a role in the regulation of myocardial lipolysis.

Effect of exercise on hormone-sensitive lipase activity in rat adipocytes

1976 ◽  
Vol 230 (2) ◽  
pp. 385-388 ◽  
Author(s):  
JA McGarr ◽  
LB Oscai ◽  
J Borensztajn
Keyword(s):  
Fatty Acids ◽  
Enzyme Activity ◽  
Adipose Tissue ◽  
Free Fatty Acids ◽  
Lipase Activity ◽  
Exercise Program ◽  
Treadmill Running ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive ◽  
Fat Pads

Hormone-sensitive lipase activity was measured in adipocytes of rats subjected to a 12-wk program of treadmill running. Enzyme activity in the runners sacrificed immediately after exercise increased 2.5-fold (P less than 0.001) in tissue exposed to epinephrine and threefold (P less than 0.001) in tissue not exposed to epinephrine, when the results were expressed per gram of adipose tissue. Increases of almost the same magnitude were observed in runners sacrificed 24 h after their last bout of work. These significant increases in enzyme activity, however, were the result of a significant reduction in the size of cells in the epididymal fat pads of the exercisers compared with those of the freely eating sedentary animals (68.7 +/- 2.7 mum vs. 82.0 +/- 2.7 mum; P less than 0.01). When the results were expressed on a per-cell basis, therefore, hormone-sensitive lipase activity, assayed in the presence or absence of epinephrine, was unaffected by the exercise program. These results provide evidence that the lipolytic capacity of adipocytes of normal, untrained rats is sufficiently large to meet the increased demand for free fatty acids imposed by the exercise program without the need for an adaptive increase in enzyme activity.

scholarly journals Hormone-stimulated lipolysis in cardiac myocytes

1983 ◽  
Vol 216 (1) ◽  
pp. 241-243 ◽  
Author(s):  
W K Palmer ◽  
T A Kane
Keyword(s):  
Fatty Acid ◽  
Cyclic Amp ◽  
Cardiac Myocytes ◽  
Diethyl Ether ◽  
Lipase Activity ◽  
Intracellular Concentration ◽  
Hormone Sensitive Lipase ◽  
Extracellular Compartment ◽  
Triacylglycerol Content ◽  
Hormone Sensitive

Type L hormone-sensitive lipase (HSL) activity was increased approx. 35% above control in cardiac myocytes incubated for 15 min with 5 nM-adrenaline. Concomitantly. adrenaline-stimulated myocytes had a lower triacylglycerol content, released more non-esterified fatty acid and had a higher intracellular concentration of cyclic AMP than did myocytes incubated without hormone. The lipase activity measured in adrenaline-stimulated and non-stimulated myocytes was stable in acetone/diethyl ether, stimulated by serum and inhibited by NaCl. These properties are consistent with the type L designation of this HSL. The finding that type L HSL is stimulated by adrenaline indicates that the enzyme that is being activated is found in the cell and not associated with an extracellular compartment of the myocardium.

Overexpression of Human Lipoprotein Lipase Increases Hormone-Sensitive Lipase Activity in Adipose Tissue of Mice

1995 ◽  
Vol 211 (3) ◽  
pp. 761-766 ◽  
Author(s):  
M. Shimada ◽  
S. Ishibashi ◽  
K. Yamamoto ◽  
M. Kawamura ◽  
Y. Watanabe ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive

Lipoprotein lipase in guinea-pig adrenals: activity, mRNA, immunolocalization and regulation by ACTH

1991 ◽  
Vol 129 (2) ◽  
pp. 213-NP ◽  
Author(s):  
M. Gåfvels ◽  
S. Vilaró ◽  
T. Olivecrona
Keyword(s):  
Guinea Pig ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Hepatic Lipase ◽  
Fold Increase ◽  
Serum Cortisol ◽  
Transitional Zone ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive ◽  
Cytoplasmic Immunoreaction

ABSTRACT Lipase activity in homogenates of guinea-pig adrenals was studied under conditions which exclude the hormone-sensitive lipase/cholesterol ester hydrolase. Antibody inhibition and chromatography on heparin–Sepharose showed that most of the activity was due to lipoprotein lipase (LPL), and that there was only a small amount of hepatic lipase activity. Northern blot analysis of total RNA demonstrated the same three adrenal LPL mRNA species (1·8, 3·1 and 3·5 kb) as were found in adipose tissue and heart. Hence, at least part of the LPL activity in adrenals is due to enzyme synthesized within the tissue. Immunolocalization showed that LPL was associated with the endothelium of blood vessels throughout the gland. In addition, there was cytoplasmic immunoreaction, suggesting that lipase was synthesized in a subpopulation of cells in the transitional zone between the fasciculata and reticularis layer of the cortex, particularly over lipid-filled cells. There was also intense immunofluorescence over scattered cells in the adrenal medulla. Treatment with an ACTH analogue depot (20 IU, i.m.) for 11 days induced a 12-fold increase in serum cortisol and increased adrenal weight 2·2-fold. The treatment induced increases in LPL mRNA (about twofold), LPL activity and in the number of cells in the adrenal cortex which gave an immunoreaction for LPL. Journal of Endocrinology (1991) 129, 213–220

Lipoprotein Lipase and Hormone-Sensitive Lipase Activities in Human Subcutaneous Lipomas: Comparison with Normal Subcutaneous Adipose Tissue

1976 ◽  
Vol 50 (4) ◽  
pp. 315-318
Author(s):  
Y. Giudicelli ◽  
R. Pecquery ◽  
B. Agli ◽  
C. Jamin ◽  
J. Quevauvilliers
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Subcutaneous Adipose Tissue ◽  
Normal Subjects ◽  
Hormone Sensitive Lipase ◽  
Lipoprotein Lipase Activity ◽  
Hormone Sensitive ◽  
Subcutaneous Adipose ◽  
Control Samples

1. Lipoprotein lipase activity and hormone-sensitive lipase activity were investigated in subcutaneous lipomas removed from two patients and compared with the enzyme activities in subcutaneous adipose tissue from two normal subjects. 2. Confirmation was obtained of the presence of lipoprotein lipase activity in lipomas with an activity fifteen to forty-five times that in the two control samples. 3. Hormone-sensitive lipase activity was demonstrated in lipomas under basal conditions of assay as well as in the presence of adrenaline plus theophylline. However, compared with the non-lipomatous fat samples, these activities were lower, as was the magnitude of the lipolytic response to adrenaline plus theophylline. 4. The significance of these measurements of enzyme activity and their role in the pathogenesis of lipomas are briefly discussed.

Relationship between type L hormone-sensitive lipase and endogenous triacylglycerol in rat heart

1984 ◽  
Vol 247 (4) ◽  
pp. R621-R625
Author(s):  
W. C. Miller ◽  
L. B. Oscai
Keyword(s):  
Lipoprotein Lipase ◽  
Cold Exposure ◽  
Lipase Activity ◽  
Rat Heart ◽  
Hormone Sensitive Lipase ◽  
Separate Experiment ◽  
Lipoprotein Lipase Activity ◽  
Physiological Conditions ◽  
Hormone Sensitive ◽  
Fat Feeding

The purpose of this study was to determine whether, under physiological conditions, intracellular lipoprotein lipase [type L hormone-sensitive lipase (HSL)] activity varied inversely with triacylglycerol (TG) content of the heart. The results show that fasting from 7:30 A.M. to 7:30 P.M. increased type L HSL activity from 72 +/- 1 to 96 +/- 1 U/g wet wt tissue (P less than 0.001) in the myocardium. At the same time, cardiac TG stores decreased from 1.83 +/- 0.03 to 1.37 +/- 0.01 mumol/g tissue (P less than 0.001). In a separate experiment, one night of eating a fat-rich diet (60% of calories from fat) caused a 42% increase in type L HSL activity, which was accompanied by a 42% reduction in the TG content of the heart. Likewise cold exposure (overnight) activated type L HSL (73%) and, at the same time, decreased cardiac TG stores (44%). When data from the fasting, fat-feeding, and cold-exposure experiments were combined, a significant correlation coefficient of -0.81 was obtained between type L HSL activity and TG content of the heart (P less than 0.001). These data provide evidence for a physiological relationship between intracellular lipoprotein lipase activity and cardiac TG content.

scholarly journals Effects of Physiological Hypercortisolemia on the Regulation of Lipolysis in Subcutaneous Adipose Tissue1

1998 ◽  
Vol 83 (2) ◽  
pp. 626-631 ◽  
Author(s):  
Jaswinder S. Samra ◽  
Mo L. Clark ◽  
Sandy M. Humphreys ◽  
Ian A. MacDonald ◽  
Peter A. Bannister ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Sodium Succinate ◽  
Hormone Sensitive Lipase ◽  
Whole Body ◽  
Constant Infusion ◽  
Nonesterified Fatty Acid ◽  
Significant Difference ◽  
Hormone Sensitive ◽  
Subcutaneous Adipose

Cortisol is known to increase whole body lipolysis, yet chronic hypercortisolemia results in increased fat mass. The main aim of the study was to explain these two apparently opposed observations by examining the acute effects of hypercortisolemia on lipolysis in subcutaneous adipose tissue and in the whole body. Six healthy subjects were studied on two occasions. On one occasion hydrocortisone sodium succinate was infused iv to induce hypercortisolemia (mean plasma cortisol concentrations, 1500 ± 100 vs. 335± 25 nmol/L; P < 0.001); on the other occasion (control study) no intervention was made. Lipolysis in the sc adipose tissue of the anterior abdominal wall was studied by measurement of arterio-venous differences, and lipolysis in the whole body was studied by constant infusion of[ 1,2,3-2H5]glycerol for measurement of the systemic glycerol appearance rate. Hypercortisolemia led to significantly increased arterialized plasma nonesterified fatty acid (NEFA; P < 0.01) and blood glycerol concentrations (P < 0.05), with an increase in systemic glycerol appearance (P < 0.05). However, in sc abdominal adipose tissue, hypercortisolemia decreased veno-arterialized differences for NEFA (P < 0.05) and reduced NEFA efflux (P < 0.05). This reduction was attributable to decreased intracellular lipolysis (P < 0.05), reflecting decreased hormone-sensitive lipase action in this adipose depot. Hypercortisolemia caused a reduction in arterialized plasma TAG concentrations (P < 0.05), but without a significant change in the local extraction of TAG (presumed to reflect the action of adipose tissue lipoprotein lipase). There was no significant difference in plasma insulin concentrations between the control and hypercortisolemia study. Site-specific regulation of the enzymes of intracellular lipolysis (hormone-sensitive lipase) and intravascular lipolysis (lipoprotein lipase) may explain the ability of acute cortisol treatment to increase systemic glycerol and NEFA appearance rates while chronically promoting net central fat deposition.

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