Lipoprotein lipase and uptake of triacylglycerol, cholesterol and phosphatidylcholine from chylomicrons by mammary and adipose tissue of lactating rats in vivo

1977 ◽  
Vol 487 (2) ◽  
pp. 297-306 ◽  
Author(s):  
Robert O. Scow ◽  
Sidney S. Chernick ◽  
T.Ruth Fleck
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase

scholarly journals Muscle-specific overexpression of lipoprotein lipase in transgenic mice results in increased α-tocopherol levels in skeletal muscle

1996 ◽  
Vol 318 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Wolfgang SATTLER ◽  
Sanja LEVAK-FRANK ◽  
Herbert RADNER ◽  
Gerhard M. KOSTNER ◽  
Rudolf ZECHNER
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Transgenic Mice ◽  
Cardiac Muscle ◽  
Lipoprotein Lipase ◽  
Excellent Correlation ◽  
Peripheral Tissues ◽  
Tissue Specific

Lipoprotein lipase (LPL) has been implicated in the delivery of chylomicron-located α-tocopherol (α-TocH) to peripheral tissues. To investigate the role of LPL in the cellular uptake of α-TocH in peripheral tissue in vivo, three lines of transgenic mice [mouse creatine kinase- (MCK) L, MCK-M and MCK-H] expressing various amounts of human LPL were compared with regard to α-TocH levels in plasma, skeletal muscle, cardiac muscle, adipose tissue and brain. Depending on the copy number of the transgene, LPL activity was increased 3- to 27-fold in skeletal muscle and 1.3- to 3.7-fold in cardiac muscle. The intracellular levels of α-TocH in skeletal muscle were significantly increased in MCK-M and MCK-H animals and correlated highly with the tissue-specific LPL activity (r = 0.998). The highest levels were observed in MCK-H (21.4 nmol/g) followed by MCK-M (13.3 nmol/g) and MCK-L (8.2 nmol/g) animals when compared with control mice (7.3 nmol/g). Excellent correlation was also observed between intracellular α-TocH and non-esterified fatty acid (NEFA) levels (r = 0.998). Although LPL activities in cardiac muscle were also increased in the transgenic mouse lines, α-TocH concentrations in the heart remained unchanged. Similarly, α-TocH levels in plasma, adipose tissue and brain were unaffected by the tissue specific overexpression of LPL in muscle. The transgenic model presented in this report provides evidence that the uptake of α-TocH in muscle is directly dependent on the level of LPL expression in vivo. Increased intracellular α-TocH concentrations with increased triglyceride lipolysis and NEFA uptake might protect the myocyte from oxidative damage during increased β-oxidation.

Triglyceride kinetics, tissue lipoprotein lipase, and liver lipogenesis in septic rats

1990 ◽  
Vol 258 (4) ◽  
pp. E678-E685 ◽  
Author(s):  
S. Lanza-Jacoby ◽  
A. Tabares
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
E Coli ◽  
Inbred Rats ◽  
Peripheral Clearance ◽  
Vldl Triglyceride ◽  
Kinetics Of

The mechanism for the development of hypertriglyceridemia during gram-negative sepsis was studied by examining liver production and clearance of very-low-density lipoprotein (VLDL) triglyceride (TG). To assess liver output and peripheral clearance the kinetics of VLDL-TG were determined by a constant iv infusion of [2-3H]glycerol-labeled VLDL. Clearance of VLDL-TG was also evaluated by measuring activities of lipoprotein lipase (LPL) in heart, soleus muscle, and adipose tissue from fasted control, fasted E. coli-treated, fed control, and fed E. coli-treated rats. Lewis inbred rats, 275-300 g, were made septic with 8 x 10(7) live E. coli colonies per 100 g body wt. Twenty-four hours after E. coli injection, serum TG, free fatty acids (FFA), and cholesterol of fasted E. coli-treated rats were elevated by 170, 76, and 16%, respectively. The elevation of serum TG may be attributed to the 67% decrease in clearance rate of VLDL-TG in fasted E. coli-treated rats compared with their fasted controls. The suppressed activities of LPL in adipose tissue, skeletal muscle, and heart were consistent with reduced clearance of TG. Secretion of VLDL-TG declined by 31% in livers of fasted E. coli-treated rats, which was accompanied by a twofold increase in the composition of liver TG. Rates of in vivo TG synthesis in livers of the fasted E. coli-treated rats were twofold higher than in those of fasted control rats. Decreased rate of TG appearance along with the increase in liver synthesis of TG contributed to the elevation of liver lipids in the fasted E. coli-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Periprandial systemic and regional lipase activity in normal humans

1996 ◽  
Vol 270 (4) ◽  
pp. E718-E722 ◽  
Author(s):  
S. W. Coppack ◽  
T. J. Yost ◽  
R. M. Fisher ◽  
R. H. Eckel ◽  
J. M. Miles
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Tissue Level ◽  
Normal Male ◽  
Arterial Plasma ◽  
Subcutaneous Abdominal Adipose Tissue ◽  
Subcutaneous Adipose

An assay for plasma lipoprotein lipase activity was used without prior injection of heparin to study arteriovenous differences of lipases across skeletal muscle and adipose tissue of normal male volunteers. Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activities and triglyceride?concentrations were measured in arterial plasma and in venous effluent plasma from forearm skeletal muscle and subcutaneous abdominal adipose tissue, in the postabsorptive state and after a mixed meal. Triglyceride clearance by the tissues was greater across adipose tissue than across muscle. There were no arteriovenous differences for HTGL activity. In the postabsorptive state skeletal muscle released LPL activity, but adipose tissue did not. Postprandially the arterial LPL and HTGL activities did not change. LPL activity in adipose tissue venous effluent rose, whereas that in muscle venous effluent decreased. These results show that the release of LPL from subcutaneous adipose and forearm tissues is regulated differently, reflecting in vivo differences in LPL regulation at the tissue level.

scholarly journals Regulation of lipoprotein lipase activity and mRNA content in rat epididymal adipose tissue in vitro by recombinant tumour necrosis factor

1990 ◽  
Vol 269 (1) ◽  
pp. 123-126 ◽  
Author(s):  
A G Mackay ◽  
J D Oliver ◽  
M P Rogers
Keyword(s):  
Adipose Tissue ◽  
Tumour Necrosis Factor ◽  
Lipoprotein Lipase ◽  
Tumour Necrosis ◽  
Epididymal Adipose Tissue ◽  
Mrna Levels ◽  
Isolated Adipocytes ◽  
Necrosis Factor

Tumour necrosis factor (TNF) has previously been shown to decrease lipoprotein lipase (LPL) activity and mRNA levels in 3T3-L1 cells and in adipose tissue from rats and guinea pigs when injected in vivo, but not to alter LPL activity in human adipocytes incubated in vitro. The effect of recombinant human TNF on LPL activity and mRNA levels in rat epididymal adipose tissue incubated in vitro was examined. LPL activity and mRNA levels fell in adipose tissue taken from fed rats and incubated in Krebs-Henseleit bicarbonate medium with glucose. The addition of insulin and dexamethasone prevented these falls. TNF (400 ng/ml) produced a fall of approx. 50% in LPL activity after 2 h of incubation and of approx. 30% in LPL mRNA levels after 3 h. TNF did not decrease LPL activity in isolated adipocytes. These results demonstrate that rat adipose tissue incubated in vitro is responsive to TNF whereas isolated adipocytes are not.

Estradiol-induced changes in lipoprotein lipase, eating, and body weight in rats

1981 ◽  
Vol 240 (5) ◽  
pp. E533-E538 ◽  
Author(s):  
I. Ramirez
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Body Weight Loss ◽  
Estradiol Benzoate ◽  
Ovariectomized Rats ◽  
Lipoprotein Lipase Activity ◽  
Adipose Tissue Lipoprotein Lipase

Daily injections of 5 micrograms estradiol benzoate (EB) for 1, 2, 3, and 12 days decreased parametrial and retroperitoneal adipose tissue lipoprotein lipase activity in ovariectomized rats. Nearly all of this decrease occurred within the 1st day. In contrast, EB-induced body weight loss and hypophagia were very slight during the 1st day after EB administration and increased substantially over the next 2 days. EB did not affect gastrocnemius muscle lipoprotein lipase activity over the first 3 days, but did decrease muscle lipoprotein lipase activity after 12 days. These changes in adipose and muscle lipoprotein lipase activity suggested that EB-induced redistribution of fuel would be greater after 3 days of treatment than after 12 days of treatment. Tests with two different in vivo triglyceride uptake methods confirmed this suggestion. EB-treated rats were hypertriglyceridemic after 12 days of treatment, but not after 3 days of treatment. Elevated plasma triglycerides were associated with an increased rate of triglyceride entry. These findings are consistent with the hypothesis that EB administration temporarily results in redistribution of triglyceride fuel from adipose tissue to muscle, resulting in a transient decrease in rate of weight gain.

scholarly journals Effects of insulin, glucocorticoids and adrenaline on the activity of rat adipose-tissue lipoprotein lipase

1980 ◽  
Vol 188 (1) ◽  
pp. 185-192 ◽  
Author(s):  
P Ashby ◽  
D S Robinson
Keyword(s):  
Protein Synthesis ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Fat Bodies ◽  
Rat Adipose Tissue ◽  
Adipose Tissue Lipoprotein Lipase

The lipoprotein lipase activity of epididymal fat-bodies from starved rats was measured during incubations at 37 degrees C in vitro. Protein synthesis independent activation of the enzyme, previously observed during incubations at 25 decrease C, also occurs at 37 degrees C. Protein-synthesis-dependent increases in the activity of the enzyme occur in the presence of insulin and are markedly potentiated by glucocorticoids. The effects on the activity of the enzyme of insulin alone, or in the presence of glucocorticoids, are correlated with its effects on total protein synthesis in the tissue. Adrenaline antagonizes the increase in activity of the enzyme brought about by insulin and abolishes the potentiation of insulin action by glucocorticoids. These changes may be due, at least in part, to its stimulation of inactivation of the enzyme in the tissue. It is suggested that changes in adipose-tissue lipoprotein lipase activity that occur with changes in nutritional status in vivo result from the combined effects of changes in plasma insulin and glucocorticoid concentrations.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

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