scholarly journals Evidence that insulin activates casein kinase 2 in rat epididymal fat-cells and that this may result in the increased phosphorylation of an acid-soluble 22 kDa protein

1991 ◽  
Vol 279 (2) ◽  
pp. 545-551 ◽  
Author(s):  
T A Diggle ◽  
C Schmitz-Peiffer ◽  
A C Borthwick ◽  
G I Welsh ◽  
R M Denton
Keyword(s):  
Adipose Tissue ◽  
Casein Kinase ◽  
Casein Kinase 2 ◽  
Fat Cells ◽  
Isolated Fat Cells ◽  
Peptide Substrate ◽  
Heat Stable ◽  
Epididymal Fat ◽  
Rat Adipose Tissue ◽  
Fat Pads

Casein kinase 2 activity as measured by phosphorylation of the peptide substrate Arg-Arg-Arg-Glu-Glu-Glu-Thr-Glu-Glu-Glu is increased by about 50% in extracts from insulin-treated epididymal fat-pads or isolated fat-cells after purification by Mono Q chromatography. Insulin acts to increase the Vmax. of the kinase. An acid-soluble protein with an apparent subunit molecular mass of about 22 kDa appears to be a substrate for casein kinase 2. The protein possesses a number of properties in common with the acid-soluble heat-stable 22 kDa protein which exhibits increased phosphorylation in rat adipose tissue exposed to insulin.

RELATIONSHIPS BETWEEN CALCIUM TRANSPORT AND THE LIPOLYTIC EFFECT OF SHEEP β-LIPOTROPIC HORMONE β-LPH) IN ADIPOSE TISSUE

1972 ◽  
Vol 69 (3) ◽  
pp. 507-516 ◽  
Author(s):  
M. Lis ◽  
C. Gilardeau ◽  
M. Chrétien
Keyword(s):  
Adipose Tissue ◽  
Intravenous Injection ◽  
Calcium Transport ◽  
Lipolytic Activity ◽  
Fat Cells ◽  
Tetraacetic Acid ◽  
Isolated Fat Cells ◽  
Fat Tissue ◽  
Adipose Cell ◽  
Epididymal Fat

ABSTRACT Intravenous injection of β-lipotropic hormone β-LPH) into rabbits caused a marked increase of Ca++ concentration in perirenal or epididymal fat tissue. β-LPH also increased the amount of Ca++ taken up during incubation of isolated fat cells. Incubation of fragments of rabbit fat tissue in presence of 45Ca and 3H mannitol indicated that Ca++ accumulated intra-cellularly after administration of β-LPH. In incubation media containing no Ca++, or containing Ca++ and the Ca++ sequestering agent EGTA (ethylenebis [oxyethylene nitrilo]-tetraacetic acid), β-LPH did not induce lipolysis. Addition of excess Ca++ to the EGTA containing medium restored lipolysis, whereas addition of EGTA to incubation mixtures containing Ca++ in which lipolysis in the presence of β-LPH was already proceeding stopped the lipolytic reaction. These results indicated that Ca++ is essential for lipolytic activity of β-LPH as it is for the lipolytic activity of ACTH and other structurally related peptides. Marked shift of Ca++ towards the adipose cell was correlated with β-LPH induced lipolysis.

scholarly journals An effect of insulin on adipose-tissue adenosine 3′:5′-cyclic monophosphate phosphodiesterase

1970 ◽  
Vol 120 (1) ◽  
pp. 187-193 ◽  
Author(s):  
E. G. Loten ◽  
J. G. T. Sneyd
Keyword(s):  
Adipose Tissue ◽  
Cyclic Amp ◽  
Cyclic Nucleotide ◽  
Fat Cells ◽  
Maximal Velocity ◽  
Isolated Fat Cells ◽  
Phosphodiesterase Activity ◽  
Cyclic Monophosphate ◽  
Cyclic Nucleotide Phosphodiesterases ◽  
Fat Pads

1. 3′:5′-Cyclic nucleotide phosphodiesterase activity was measured in homogenates prepared from epididymal fat-pads and isolated fat-cells incubated in the absence and presence of insulin. 2. Homogenates of insulin-treated tissues showed an increase in phosphodiesterase activity compared with controls. No effect of insulin was observed when the hormone was added directly to homogenates. 3. There was kinetic evidence for the presence of two 3′:5′-cyclic nucleotide phosphodiesterases in adipose tissue. Insulin raised the maximal velocity of the low-Km enzyme and lowered the Km of the higher-Km enzyme. 4. It is suggested that the effect of insulin on adipose tissue phosphodiesterase accounts for the ability of this hormone to lower cyclic-AMP concentration in the tissue.

scholarly journals The effect of insulin on the washout of [45Ca]calcium from adipocytes and soleus muscle of the rat

1977 ◽  
Vol 164 (1) ◽  
pp. 251-255 ◽  
Author(s):  
T Clausen ◽  
B R Martin
Keyword(s):  
Soleus Muscle ◽  
Rat Plasma ◽  
Fat Cells ◽  
Isolated Fat Cells ◽  
Epididymal Fat ◽  
Fat Pads

Insulin stimulates the washout of 45Ca from preloaded isolated fat-cells, whole epididymal fat-pads and isolated soleus muscles of the rat. This effect occurs within 10 min after the addition of the hormone, and it can be detected at concentrations down to those measured in rat plasma. When K+ is omitted from the washout medium, the effect on soleus muscles is more pronounced and increases with the time of exposure.

scholarly journals The glycerol phosphate, dihydroxyacetone phosphate and monoacylglycerol pathways of glycerolipid synthesis in rat adipose-tissue homogenates

1976 ◽  
Vol 160 (3) ◽  
pp. 693-700 ◽  
Author(s):  
P F Dodds ◽  
M I Gurr ◽  
D N Brindley
Keyword(s):  
Adipose Tissue ◽  
Dihydroxyacetone Phosphate ◽  
Glycerol Phosphate ◽  
Epididymal Fat ◽  
Tissue Homogenates ◽  
Glycerolipid Synthesis ◽  
Acyl Acceptors ◽  
Rat Adipose Tissue ◽  
Fat Pads

1. Fat-free homogenates from the epididymal fat-pads of rats were used to measure the rate of palmitate esterification with different substrates. The effectiveness of the acyl acceptors decreased in the order glycerol phosphate, dihydroxyacetone phosphate, 2-octadecenyl-glycerol and 2-hexadecylglycerol. 2. Glycerol phosphate and dihydroxyacetone phosphate inhibited their rates of esterification in a mutually competitive manner. 3. The esterification of glycerol phosphate was also inhibited in a partially competitive manner by 2-octadecenylglycerol and to a lesser extent by 2-hexadecylglycerol. However, glycerol phosphate did not inhibit the esterification of 2-octadecenylglycerol. 4. The esterification of dihydroxyacetone phosphate and 2-hexadecylglycerol was more sensitive to inhibition by clofenapate than was that of glycerol phosphate. Norfenfluramine was more effective in inhibiting the esterification of 2-hexadecylglycerol than that of glycerol phosphate or dihydroxyacetone phosphate. 5 It is concluded that rat adipose tissue can synthesize glycerolipids by three independent routes.

The Effect of Age on Deoxyribonucleic Acid Synthesis in Rat Adipose Tissue

1975 ◽  
Vol 48 (4) ◽  
pp. 323-325
Author(s):  
B. M. Lewis ◽  
T. M. Hayes
Keyword(s):  
Adipose Tissue ◽  
Deoxyribonucleic Acid ◽  
Age Groups ◽  
Acid Synthesis ◽  
Fat Cells ◽  
Deoxyribonucleic Acid Synthesis ◽  
Old Rats ◽  
Rat Adipose Tissue ◽  
Effect Of Age ◽  
Fat Pads

1. Rats of four different age groups were injected intraperitoneally with labelled thymidine and killed 1, 7 or 12 days later. 2. The epididymal fat-pads were separated into fat-cells and stromal elements by collagenase digestion. 3. The incorporation of labelled thymidine into the deoxyribonucleic acid (DNA) of both fractions was greatest in the 6-week-old animals. Uptake was significantly decreased in 12- and 15-week-old animals and was lowest in 22-week-old rats.

scholarly journals Rat epididymal adipose tissue acetyl-CoA carboxylase

1970 ◽  
Vol 48 (8) ◽  
pp. 915-921 ◽  
Author(s):  
P. R. Desjardins ◽  
K. Dakshinamurti
Keyword(s):  
Adipose Tissue ◽  
Epididymal Adipose Tissue ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Ph Optimum ◽  
Epididymal Fat ◽  
Ph Dependent ◽  
Rat Adipose Tissue ◽  
Cold Inactivation ◽  
Fat Pads

The properties of a partially purified acetyl-CoA carboxylase (acetyl-CoA:CO2 ligase (ADP), EC 6.4.1.2) from rat epididymal fat pads have been studied. The properties of the rat adipose tissue enzyme are similar to those of the liver in regard to the pH optimum and affinity for substrates and inhibitors. The rat adipose tissue carboxylase shows a pH-dependent, reversible cold inactivation.

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