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.

scholarly journals Effects of glucose and insulin on the activation of lipoprotin lipase and on protein-synthesis in rat adipose tissue

1980 ◽  
Vol 188 (1) ◽  
pp. 193-199 ◽  
Author(s):  
S M Parkin ◽  
K Walker ◽  
P Ashby ◽  
D S Robinson
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Specific Activity ◽  
The Other ◽  
Lipoprotein Lipase Activity ◽  
Fat Bodies ◽  
Rat Adipose Tissue ◽  
Adipose Tissue Lipoprotein Lipase

Glucose, and certain sugars that can readily be converted to glucose 6-phosphate, bring about an activation of adipose-tissue lipoprotein lipase when epididymal fat-bodies from starved rats are incubated in the presence of cycloheximide. Other substrates do not support the activation. If the tissue is preincubated in the presence of cycloheximide for longer than 2h, the ability of added glucose to activate the enzyme is lost. On the other hand, the addition of glucose still brings about an increase in lipoprotein lipase activity after preincubation in the absence of cycloheximide for as long as 4h. The magnitude of the increase in enzyme activity brought about by the addition of glucose is increased when protein synthesis is stimulated during the preincubation period by insulin. The results are interpreted in terms of the existence in adipose tissue of a proenzyme pool of lipoprotein lipase that is normally maintained by protein synthesis and that is converted to complete enzyme of higher specific activity by a process that specifically requires glucose.

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.

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 Increase in Lipoprotein Lipase Activity in Isolated Rat Adipose Tissue by Selenate.

1993 ◽  
Vol 16 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Hiroshi UEKI ◽  
Yusuke OHKURA ◽  
Toshio MOTOYASHIKI ◽  
Nobuaki TOMINAGA ◽  
Tetsuo MORITA
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Lipoprotein Lipase Activity ◽  
Rat Adipose Tissue ◽  
Isolated Rat
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