scholarly journals Stability of clearing-factor lipase in rat adipose tissue

1973 ◽  
Vol 136 (2) ◽  
pp. 437-439 ◽  
Author(s):  
P. Davies ◽  
D. S. Robinson
Keyword(s):  
Adipose Tissue ◽  
Total Activity ◽  
Fat Cells ◽  
Fat Cell ◽  
The Stability ◽  
Rat Adipose Tissue

The stability at 42°C of clearing-factor lipase in adipose tissue, and in intact fat-cells isolated from it, was investigated. That portion of the total activity of the tissue which is associated with the fat-cell is stable under such conditions. This stability is markedly diminished when the fat-cell is disrupted.

scholarly journals Effect of nutrition on subcellular localization of rat fat-cell lipoprotein lipase

1978 ◽  
Vol 172 (2) ◽  
pp. 239-245 ◽  
Author(s):  
A Vanhove ◽  
C Wolf ◽  
M Breton ◽  
M C Glangeaud
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Plasma Membranes ◽  
Total Activity ◽  
Normal Diet ◽  
Epididymal Adipose Tissue ◽  
Fat Cells ◽  
Isolated Fat Cells ◽  
Fat Cell ◽  
Intact Tissue

This study supports the possibility for multiple subcellular forms of lipoprotein lipase. 1. The total activity of lipoprotein lipase per g of intact epididymal adipose tissue from fed rats is much higher than that from starved rats. 2. The isolated fat-cells of fed and of starved rats have lipoprotein lipase of almost the same activity per g of fat-pads. The isolated fat-cells of starved rats have a much higher proportion of total activity per g of the intact tissue than do those of fed rats. 3. Under the conditions of homogenization used, only a small proportion of the total activity per g of intact tissue from fed rats was associated with the fat layer which floated to the top of the homogenate during low-speed centrifugation. The different proportions of the specific enzyme activity found in each subcellular fraction are described. 4. Lipoprotein lipase from plasma membranes and microsomal fractions from starved and fed rats was purified by affinity chromatography. 5. The total activity of microsomal lipoprotein lipase per g of intact adipose tissue is enhanced by a normal diet. 6. In intact epididymal adipose tissue from fed rats, the activity per g of tissue of lipoprotein lipase of plasma membranes is much higher than that in the same fraction from starved rats. By contrast, the activities per g of tissue in plasma membranes obtained from starved or from fed rats by collagenase treatment were similar.

scholarly journals Clearing-factor lipase in adipose tissue. Distinction of different states of the enzyme and the possible role of the fat cell in the maintenance of tissue activity

1969 ◽  
Vol 112 (2) ◽  
pp. 203-209 ◽  
Author(s):  
V. J. Cunningham ◽  
D S Robinson
Keyword(s):  
Adipose Tissue ◽  
Lipase Activity ◽  
Total Activity ◽  
Epididymal Adipose Tissue ◽  
Fat Cells ◽  
Isolated Fat Cells ◽  
Fat Cell ◽  
Prolonged Incubation ◽  
Intact Tissue

1. Incubation of intact epididymal adipose tissue from fed rats at 37° in an albumin solution at pH7·4 in vitro results in rapid loss of clearing-factor lipase activity until a low activity, stable to prolonged incubation, is attained. The clearing-factor lipase activity of intact tissue from starved rats, which is initially much less than that of tissue from fed rats, is mainly stable to incubation at 37°. 2. Much of the clearing-factor lipase activity of intact epididymal adipose tissue from fed rats is inactivated by collagenase. The enzyme activity of intact tissue from starved rats is not inactivated by collagenase. 3. The clearing-factor lipase activity of fat cells isolated from the epididymal adipose tissue of fed rats is stable to prolonged incubation at 37°. It represents only a small proportion of the total activity of the intact tissue. In starved rats, the isolated fat cells contain a much higher proportion of the activity of the intact tissue. Their activity is also stable at 37°. 4. Incubation of isolated fat cells in a serum-based medium leads to a progressive rise in clearing-factor lipase activity. Actinomycin increases the extent of this rise in activity. No rise in clearing-factor lipase activity occurs when stromal-vascular cells isolated from epididymal adipose tissue are incubated in the medium. 5. The findings indicate that less than 20% of the activity of intact adipose tissue from fed rats is retained when fat cells are isolated from the tissue by collagenase treatment. The activity that is lost could be that which normally functions in the uptake of triglyceride fatty acids by the tissue.

Water content of rat adipose tissue and isolated adipocytes in relation to cell size

1976 ◽  
Vol 231 (5) ◽  
pp. 1568-1572 ◽  
Author(s):  
M DiGirolamo ◽  
JL Owens
Keyword(s):  
Adipose Tissue ◽  
Water Content ◽  
Cell Volume ◽  
Cell Size ◽  
Intracellular Water ◽  
Male Rats ◽  
Fat Cells ◽  
Fat Cell ◽  
Tissue Water ◽  
Adipose Mass

Epididymal adipose tissue composition and adipocyte water content were studied in male rats during growth and development of spontaneous obesity. The data show that a highly significant positive correlation exists between fat-cell volume and intracellular water space (IWS) (r=.967, P less than .001). Intracellular water, expressed as picoliters per fat cell, varied from 1.5-2 in small fat cells (mean vol, 30-50 pl) to 9-10 in large cells (800-1,000 pl). When expressed as percent of fat-cell volume, IWS varied from 5-7% in the small fat cells to 1-1.3% in the large ones. Total adipose tissue water continued to increase with increasing adipose mass. Similarly, total adipocyte water increased with enlarging cell size and tissue mass. The contribution of total adipocyte water (as contrasted to that of nonadipocyte water) to total tissue water, however, was found to be limited (less than 23%) and to decline progressively with adipose mass expansion.

Metabolic influences on enzymes of glycogen synthesis and breakdown in adipose tissue

1964 ◽  
Vol 207 (6) ◽  
pp. 1215-1220 ◽  
Author(s):  
Alisa Gutman ◽  
Eleazar Shafrir
Keyword(s):  
Adipose Tissue ◽  
Protein Content ◽  
Glycogen Synthesis ◽  
Total Activity ◽  
Epididymal Adipose Tissue ◽  
Control Value ◽  
Prolonged Fast ◽  
Rat Adipose Tissue

Rat adipose tissue from different body sites was shown to contain uridine diphosphoglucose (UDPG)-transglucosylase activity, which on the basis of protein content was comparable to or higher than that reported for muscle or liver. In epididymal adipose tissue, the activity of UDPG-glycogen transglucosylase and phosphorylase, as well as the content of glycogen per wet weight, decreased with increasing age of the animals in parallel with the decrease of tissue protein content. On prolonged fast the activity of UDPG-glycogen transglucosylase and phosphorylase per milligram protein dropped by 25–50% of the control value. On refeeding, the extent of changes was variable but, in general, at 24 hr control or higher levels of activity were reached and at 48 hr the activities were elevated. The ratio of glucose 6-phosphate independent activity of UDPG-glycogen transglucosylase to total activity was not affected by fasting and refeeding or by the administration of glucose with insulin. In adrenalectomized rats, with high adipose tissue glycogen, no change in UDPG-glycogen transglucosylase was found, whereas the levels of phosphorylase were elevated. Epinephrine in vivo and in vitro did not affect the activity of UDPG-glycogen transglucosylase of adipose tissue.

scholarly journals Methionine requirement of kittens given amino acid diets containing adequate cystine

1983 ◽  
Vol 49 (3) ◽  
pp. 411-417 ◽  
Author(s):  
Katherine A. Smalley ◽  
Quinton R. Rogers ◽  
James G. Morris
Keyword(s):  
Adipose Tissue ◽  
Cell Size ◽  
Muscle Tissue ◽  
Dna Content ◽  
Shoulder Joint ◽  
Subcutaneous Adipose Tissue ◽  
Fat Cells ◽  
Fat Cell ◽  
Fat Cell Size ◽  
Subcutaneous Adipose

1. The effects of feeding either high-protein (HP) or low-protein (LP) diets between 1.8 and 15 kg live weight (LW) and a low-energy (LE) or high-energy (HE) intake subsequently on the cellularity of muscle and adipose tissue in pigs growing to 75 kg LW were investigated.2. The effects of the nutritional treatments on muscle tissue were assessed from the weight and DNA content of the m. adductor. For adipose tissue the total DNA content and fat cell size of the subcutaneous adipose tissue contained in the left shoulder joint were determined.3. Feeding the LP diets in early life reduced the weight and DNA content of the m. adductor (P < 0.01) and increased fat cell size (P < 0.01) at 15 kg LW.4. Subsequent to 15 kg there was an almost linear increase in muscle DNA with increasing LW, and the difference between pigs from the initial protein treatments progressively diminished and was no longer apparent at 60 kg LW.5. At 30 kg LW, pigs given the LP diets before 15 kg LW contained less DNA in the subcutaneous adipose tissue from the shoulder joint (P < 0.01) and had larger fat cells (P < 0.05) than pigs given the HP diets initially. However, adipose DNA and fat cell size increased with increasing LW and the differences resulting from the initial protein treatments progressively diminished. On the LE and HE treatments subsequent to 15 kg these differences were no longer evident at 45 and 60 kg respectively.6. Pigs given the HE intake subsequent to 15 kg, contained less DNA in muscle tissue (P < 0·05) at 60 and 75 kg LW and had larger fat cells (P < 0·05) at 45, 60 and 75 kg LW, than pigs on the LE treatment.

scholarly journals Fish Oil-induced Yellow Fat Disease in Rats; II. Enzyme Histochemistry of Adipose Tissue

1978 ◽  
Vol 15 (1) ◽  
pp. 125-132 ◽  
Author(s):  
L. H. J. C. Danse ◽  
W. A. Steenbergen-Botterweg
Keyword(s):  
Adipose Tissue ◽  
Acid Phosphatase ◽  
Fish Oil ◽  
Esterase Activity ◽  
Membrane Damage ◽  
Nonspecific Esterase ◽  
Fat Cells ◽  
Nucleotidase Activity ◽  
Fat Cell ◽  
Cell Degeneration

Adipose tissue in various stages of fish oil-induced yellow fat disease in the rat had the same acid phosphatase and 5-nucleotidase activity pattern as similar stages of the disorder in mink and pig. A weak acid phosphatase and 5-nucleotidase activity was seen in interstitial lipofuscin-laden macrophages in “stage M” yellow fat disease without fat cell degeneration. Activity of these macrophagic enzymes increased when there was fat cell degeneration (“stage S” and “stage E” yellow fat disease). This different phosphatase activity in the same cell type may result from phagocytosis of substrates with variable digestibility. Macrophages directly surrounding affected fat cells in steatitis areas (“stage S” and “stage E”) had strong acid phosphatase and 5-nucleotidase activity. As in the pig, increased 5-nucleotidase activity was found in affected fat cells, which probably indicates plasma membrane damage. Increased nonspecific esterase activity occurred around affected fat cells. Only a small part of this esterase activity originated from inflammatory cells. This indicates that an increase of esterase activity in degenerating adipose tissue may be an endogeneous process in this tissue.

Increased activities of mitochondrial enzymes in white adipose tissue in trained rats

1991 ◽  
Vol 261 (3) ◽  
pp. E410-E414 ◽  
Author(s):  
B. Stallknecht ◽  
J. Vinten ◽  
T. Ploug ◽  
H. Galbo
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Tricarboxylic Acid Cycle ◽  
Oxidative Capacity ◽  
Female Rats ◽  
Male Rats ◽  
Mitochondrial Enzymes ◽  
Fat Cells ◽  
Fat Cell ◽  
Respiratory Chain Enzyme

During earlier fat cell studies we noticed that homogenates of white fat cells became more brown with training, a fact that might reflect an increased content of mitochondria. This raised the question whether training (as is the case in muscle) increases the oxidative capacity in fat cells. Groups of 8-12 rats were swim trained for 10 wk or served as either sedentary, sham swim-trained, or cold-stressed controls. White adipose tissue was removed, and the activities of the respiratory chain enzyme cytochrome-c oxidase (CCO) and of the enzyme malate dehydrogenase (MDH), which participates in the tricarboxylic acid cycle as well as in the mitochondrial malate-aspartate and acetyl-group shuttles, were determined. The CCO and MDH activities expressed per milligram protein were increased in male rats 4.4- and 2.8-fold, respectively, in the swim-trained compared with the sham swim-trained rats (P less than 0.05). In female rats the CCO activity expressed per milligram protein was increased 4.5-fold in the trained compared with the sedentary control rats (P less than 0.01). Neither cold stress nor sham swim training increased CCO or MDH activities in white adipose tissue (P greater than 0.05). In conclusion, in rats, intensive endurance training induces an increase in mitochondrial enzyme activities in white adipose tissue as is seen in skeletal muscle.

Historical perspectives in fat cell biology: the fat cell as a model for the investigation of hormonal and metabolic pathways

2012 ◽  
Vol 302 (2) ◽  
pp. C327-C359 ◽  
Author(s):  
Max Lafontan
Keyword(s):  
Adipose Tissue ◽  
Hormonal Regulation ◽  
Cell Biology ◽  
Metabolic Regulation ◽  
Hormone Receptors ◽  
Fat Cells ◽  
Fat Cell ◽  
Cellular Mechanisms ◽  
Historical Perspectives ◽  
Stroma Vascular Fraction

For many years, there was little interest in the biochemistry or physiology of adipose tissue. It is now well recognized that adipocytes play an important dynamic role in metabolic regulation. They are able to sense metabolic states via their ability to perceive a large number of nervous and hormonal signals. They are also able to produce hormones, called adipokines, that affect nutrient intake, metabolism and energy expenditure. The report by Rodbell in 1964 that intact fat cells can be obtained by collagenase digestion of adipose tissue revolutionized studies on the hormonal regulation and metabolism of the fat cell. In the context of the advent of systems biology in the field of cell biology, the present seems an appropriate time to look back at the global contribution of the fat cell to cell biology knowledge. This review focuses on the very early approaches that used the fat cell as a tool to discover and understand various cellular mechanisms. Attention essentially focuses on the early investigations revealing the major contribution of mature fat cells and also fat cells originating from adipose cell lines to the discovery of major events related to hormone action (hormone receptors and transduction pathways involved in hormonal signaling) and mechanisms involved in metabolite processing (hexose uptake and uptake, storage, and efflux of fatty acids). Dormant preadipocytes exist in the stroma-vascular fraction of the adipose tissue of rodents and humans; cell culture systems have proven to be valuable models for the study of the processes involved in the formation of new fat cells. Finally, more recent insights into adipocyte secretion, a completely new role with major metabolic impact, are also briefly summarized.

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