Increased response of adipose tissue of the ob/ob mouse to the action of adrenaline after treatment with thyroxin

1977 ◽  
Vol 55 (6) ◽  
pp. 1320-1329 ◽  
Author(s):  
N. Bégin-Heick ◽  
H. M. C. Heick
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Epididymal Adipose Tissue ◽  
Lipolytic System ◽  
Low K ◽  
Fatty Acid Mobilization

The activity of the lipolytic system of the obese hyperglycemic mouse was assessed after treatment with physiological doses of thyroxin (T4). The treatment significantly increased fatty acid mobilization in response to adrenaline over the levels observed in the control mice under all conditions studied. The activities of the high- and low-Km phosphodiesterases and of adenylate cyclase were also studied. Treatment of the ob/ob mice with T4 had little effect on the activities of the cyclic AMP phosphodiesterases (high and low Km) but it partially restored the activity of adenylate cyclase, which is deficient in these animals. A correlation was found in the T4-treated obese animals between the ability of the epididymal adipose tissue to mobilize fatty acids, its ability to increase the intracellular levels of cyclic AMP, and the activity of adenylate cyclase in response to adrenaline stimulation.

Adipose tissue in experimental nephrotic syndrome

1963 ◽  
Vol 205 (4) ◽  
pp. 702-706 ◽  
Author(s):  
Alisa Gutman ◽  
Eleazar Shafrir
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Nephrotic Syndrome ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Lipoprotein Lipase ◽  
Epididymal Adipose Tissue ◽  
Adequate Nutrition ◽  
Defective Metabolism ◽  
Inadequate Food Intake

Epididymal adipose tissue of aminonucleoside-treated rats, investigated 3 to 6 days after induction of the nephrotic syndrome, had low glycogen levels and showed impaired esterification of free fatty acids and assimilation of lipoprotein triglyceride and markedly reduced liberation of lipoprotein lipase. These results were found to be influenced by the inadequate food intake of the acutely nephrotic animals and comparable to the values of control rats fasted for 2 days. On return to adequate nutrition, which occurred 12–20 days after aminonucleoside treatment, adipose tissue glycogen and free fatty acid assimilation returned toward normal levels but lipoprotein-lipase liberation remained below normal. In rats rendered nephrotic by antikidney serum, the assimilation of free fatty acids and lipoprotein-triglyceride by adipose tissue was impaired in spite of only minor reduction in food consumption. The results indicate that the defective metabolism of adipose tissue in nephrotic animals may be contributory to the nephrotic hypertriglyceridemia.

CONVERSION OF METHIONINE AND THREONINE TO FATTY ACIDS BY ADIPOSE TISSUE

1963 ◽  
Vol 41 (1) ◽  
pp. 269-273 ◽  
Author(s):  
D. D. Feller ◽  
E. Feist
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Epididymal Adipose Tissue

Epididymal adipose tissue was incubated with uniformly labelled (14C)-methionine, (2-14C)-methionine, and uniformly labelled (14C)-threonine. Each of these compounds is actively metabolized by adipose tissue, as evidenced by the generation of 14CO2 and (14C)-fatty acid. Evidence was gathered in regard to the intermediary pathways by which these amino acids are utilized by adipose tissue and the general conclusion is drawn that these pathways are similar to those postulated for other tissues. These experiments further emphasize the central role that propionate plays in adipose tissue lipogenesis.

Uncoupling of Lipolysis from Cyclic AMP by Procaine: a Tool for Studying the Mechanism of Action of Antilipolytic Agents

1975 ◽  
Vol 53 (4) ◽  
pp. 603-609 ◽  
Author(s):  
Mario D'Costa ◽  
Aubie Angel
Keyword(s):  
Adipose Tissue ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Mechanism Of Action ◽  
Initial Rate ◽  
Direct Action ◽  
Inhibitory Effect ◽  
Glycerol Release ◽  
Cyclic Amp Accumulation ◽  
Low K

The initial rate of net glycerol release in norepinephrine-stimulated adipose tissue fragments was inhibited (40–78%) by procaine–HCl (1–5 mM), whereas basal (unstimulated) lipolysis was unaffected. A dose-related inhibition of norepinephrine-induced lipolysis by procaine–HCl (0.1–1 mM) also occurred in adipocytes. Procaine-induced antilipolysis was associated with an augmented rather than a reduced hormone-stimulated increment in intracellular cyclic AMP. The dissociation of lipolysis from cyclic AMP accumulation has been termed the uncoupling effect of procaine. This effect of procaine was employed to define the precise mechanism of action of the antilipolytic drug clofibrate (Atromid-S®) which inhibits lipolysis by reducing cyclic AMP. A reduction in cyclic AMP by clofibrate was demonstrated in norepinephrine-stimulated cells exposed to procaine (uncoupled system). Thus, the inhibitory effect of clofibrate on cyclic AMP could not be attributed to accumulation of products of lipolysis. Because neither procaine–HCl nor clofibrate had any effect on the low Km 3′:5′-cyclic-AMP phosphodiesterase (EC 3.1.4.17) activity in hormone stimulated cells, the clofibrate-induced reduction in cyclic AMP was attributed to its direct action on adipocyte adenylate cyclase.

LIPOGENESIS IN ADIPOSE TISSUE OF MEAL-FED RATS: A POSSIBLE REGULATORY ROLE OF α-GLYCEROPHOSPHATE FORMATION

1967 ◽  
Vol 45 (2) ◽  
pp. 201-214 ◽  
Author(s):  
Gilbert A. Leveille
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Incubation Medium ◽  
Control Mechanism ◽  
Acid Synthesis ◽  
Fatty Acyl ◽  
Epididymal Adipose Tissue ◽  
Malic Dehydrogenase

The incorporation of acetate-1-14C into fatty acids by isolated epididymal adipose tissue of fed and fasted rats adapted to a single daily 2-hour meal (meal eaters) or fed ad libitum (nibblers) was investigated. Fasting (22 hours) markedly depressed lipogenesis whereas fatty acid synthesis increased linearly with time of refeeding in meal-fed but not in nibbling rats. The activities of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and NADP-malic dehydrogenase in adipose tissue of meal-fed or nibbling rats were not altered as a consequence of a 22-hour fast or of subsequent feeding for 2 hours. The incorporation of acetate-1-l4C into fatty acids by adipose tissue of fasted meal-eating or nibbling animals was markedly enhanced by the addition of unlabeled pyruvate or oxaloacetate to the incubation medium. This stimulatory effect was not observed with adipose tissue front fed meal-eating rats. The addition of unlabeled glucose and insulin to the incubation medium markedly enhanced acetate-1-14C incorporation into fatty acids by isolated adipose tissue and completely overcame any effect of fasting. Adipose tissue converted pyruvate-1-14C, -2-14C, or -3-14C to fatty acids and glyceride-glycerol. The results obtained are consistent with the functioning of a pathway in adipose tissue involving mitochondrial carboxylation of pyruvate to oxaloacetate, and equilibration of the newly formed oxaloacetate with malate and fumarate, followed by cytoplasmic conversion of oxaloacetate to phosphoenol pyruvate. The data are interpreted to support a control mechanism in which fatty acid synthesis is inhibited by tissue fatty acids and fatty acyl-CoA derivatives. The inhibition could in turn be reduced by the availability of α-glycerophosphate, for the esterification of fatty acids. This control mechanism is proposed as the explanation for the refeeding response observed in adipose tissue of meal-fed rats.

Lipogenesis in the sand rat (Psammomys obesus)

1983 ◽  
Vol 244 (5) ◽  
pp. E480-E486 ◽  
Author(s):  
B. Kalderon ◽  
J. H. Adler ◽  
E. Levy ◽  
A. Gutman
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthetase ◽  
Epididymal Adipose Tissue ◽  
Albino Rats ◽  
Hepatic Lipogenesis ◽  
Very Low Density Lipoproteins ◽  
Sand Rat

Synthesis of fatty acids was measured in the liver and in epididymal adipose tissue of sand rats and albino rats. In chow-fed sand rats the rate of hepatic lipogenesis, as measured by the incorporation of 3H2O into fatty acids, was four- to sevenfold higher than in albino rats and in sand rats on a low-calorie saltbush diet. The contribution of [14C]glucose to lipogenesis in sand rat liver was lower than in albino rats. In fed sand rats lipogenesis incorporating 3H2O was stimulated by casein but not by glucose. In adipose tissue, lipogenesis measured 1 h after administration of 3H2O was much lower in sand rats than in albino rats. In vitro incorporation of [14C]glucose or acetate into adipose tissue fatty acids was negligible. In adipose tissue, uptake of very-low-density lipoproteins (VLDL) and lipoprotein lipase activity were sevenfold higher than in albino rats. Activities of NADP-malate dehydrogenase, acetyl CoA carboxylase, and fatty acid synthetase were considerably higher in the liver of chow-fed sand rats than in albino rats. It was concluded that obesity in sand rats originates from hepatic lipogenesis without a significant contribution of local fatty acid synthesis in adipose tissue.

3′:5′-Cyclic-AMP Phosphodiesterase Activities in White and Brown Adipose Tissues of Cold-Acclimated Rats

1975 ◽  
Vol 53 (12) ◽  
pp. 1301-1308 ◽  
Author(s):  
R. Bertin ◽  
R. Portet
Keyword(s):  
Adipose Tissue ◽  
Cyclic Amp ◽  
Specific Activity ◽  
Epididymal Adipose Tissue ◽  
Interscapular Brown Adipose Tissue ◽  
Cyclic Amp Phosphodiesterase ◽  
High K ◽  
Brown Adipose ◽  
Tissue Homogenates ◽  
Low K

3′:5′-Cyclic-AMP phosphodiesterase (PDE) (EC 3.1.4.17) activity was measured in interscapular brown adipose tissue (BAT) and in white epididymal adipose tissue of rats acclimated to constant or fluctuating cold. Experiments were carried out on isolated adipocytes or tissue homogenates. In brown or white adipose tissue or isolated adipocyte homogenates, two different apparent Km values were found according to the substrate (cAMP) concentration. The low Km was at about 10−6 M and the high one at about 10−4 M. The apparent V of the high Km enzyme was about 10-fold higher than the V of the low Km enzyme. Cold acclimation to constant or fluctuating cold did not modify appreciably the Km or V values. For low substrate concentrations (10−6–10−8 M), the specific activity of PDE expressed per milligram of protein was decreased in BAT adipocytes of the two groups of cold-acclimated rats, compared to controls. Inversely, it was increased in total tissue homogenates. These variations were smaller in fluctuating cold than in constant cold-acclimated rats. They could, in part, induce the increases in lipolysis and in blood flow observed in the BAT of cold-acclimated rats.

Fatty Acid Synthesis from Pyruvate in White Adipose Tissue: the Effect of Norepinephrine

1971 ◽  
Vol 49 (6) ◽  
pp. 736-741 ◽  
Author(s):  
M. L. Halperin
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Pentose Phosphate ◽  
Epididymal Adipose Tissue ◽  
Phenazine Methosulfate ◽  
Fasted Rats ◽  
Lines Of Evidence

Pyruvate incorporation into fatty acids has been studied in epididymal adipose tissue taken from normal and 24-h-fasted rats. This rate was limited by the rate of cytoplasmic NADPH2 generation as suggested by three lines of evidence.(1) D-Glucose-12C increased pyruvate-U-14C incorporation into fatty acids threefold. This augmentation was independent of L-glycerol 3-phosphate concentrations as the level of this metabolite was not increased. Addition of lactate-U-14C to the pyruvate medium increased the tissue L-glycerol 3-phosphate levels but did not increase the rate of fatty acid synthesis.(2) Phenazine methosulfate (2 μM) inhibited pyruvate or pyruvate plus lactate (L/P = 3/1) conversion to fatty acids whilst stimulating fatty acid synthesis from glucose or lactate alone.(3) Norepinephrine stimulated pyruvate but not glucose or glucose plus pyruvate incorporation into fatty acids. This correlated with norepinephrine-induced glycogenosis and NADPH2 production in the pentose phosphate pathway. This was shown by increased 1-14CO2/6-14CO2 production from endogenously labelled glycogen and the absence of this effect in glycogen-depleted adipocytes (24-h-fasted rats).

Selectivity of fatty acid mobilization: a general metabolic feature of adipose tissue

1995 ◽  
Vol 269 (5) ◽  
pp. R1060-R1067 ◽  
Author(s):  
T. Raclot ◽  
E. Mioskowski ◽  
A. C. Bach ◽  
R. Groscolas
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Chain Length ◽  
Acid Composition ◽  
Fat Cells ◽  
Adipose Tissues ◽  
Metabolic Feature ◽  
Fatty Acid Mobilization

This study extends our earlier work (T. Raclot and R. Groscolas. J. Lipid Res. 34: 1515-1526, 1993), which showed that, under norepinephrine-stimulated lipolysis, fatty acids of rat retroperitoneal fat cells are selectively mobilized. The present study examines whether this selective mobilization of fatty acids 1) is based on their proportions in adipose tissue, 2) is a metabolic feature common to all adipose tissues, and/or 3) depends on the lipolysis-stimulating agent. Rat fat cells with two markedly different fatty acid compositions were isolated from four white adipose tissues and treated with three lipolytic agents. Fatty acid composition of in vitro released free fatty acids was compared with that of fat cell triacylglycerols, the ratio of percent in free fatty acid to percent in triacylglycerol being defined as the relative mobilization rate (RMR). The RMR of individual fatty acids was related to their molecular structure. It increased exponentially with unsaturation for a given chain length and decreased with increasing chain length for a given unsaturation. The selectivity of fatty acid mobilization was similar regardless of the fatty acid composition of adipose tissue, the tissue location, and the lipolytic agent used. Under conditions of stimulated lipolysis, the selectivity of fatty acid mobilization is therefore a general metabolic feature of adipose tissue. Fatty acids with 16-20 carbon atoms and 4 or 5 double bonds had the highest RMR (from 1.4 to > 5), whereas fatty acids with 20-22 carbon atoms and 0 or 1 double bond had the lowest RMR (from 0.3 to 0.7). For the other fatty acids, RMR was close to unity.(ABSTRACT TRUNCATED AT 250 WORDS)

CONVERSION OF METHIONINE AND THREONINE TO FATTY ACIDS BY ADIPOSE TISSUE

1963 ◽  
Vol 41 (2) ◽  
pp. 269-273 ◽  
Author(s):  
D. D. Feller ◽  
E. Feist
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Epididymal Adipose Tissue

Epididymal adipose tissue was incubated with uniformly labelled (14C)-methionine, (2-14C)-methionine, and uniformly labelled (14C)-threonine. Each of these compounds is actively metabolized by adipose tissue, as evidenced by the generation of 14CO2 and (14C)-fatty acid. Evidence was gathered in regard to the intermediary pathways by which these amino acids are utilized by adipose tissue and the general conclusion is drawn that these pathways are similar to those postulated for other tissues. These experiments further emphasize the central role that propionate plays in adipose tissue lipogenesis.

Platelet Aggregation in Finnish Men and Its Relation to Fatty Acids in Platelets, Plasma and Adipose Tissue

1985 ◽  
Vol 54 (03) ◽  
pp. 563-569 ◽  
Author(s):  
M K Salo ◽  
E Vartiainen ◽  
P Puska ◽  
T Nikkari
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Acid Composition ◽  
Saturated Fatty Acids ◽  
Free Living ◽  
Ω3 Fatty Acids ◽  
Induced Aggregation

SummaryPlatelet aggregation and its relation to fatty acid composition of platelets, plasma and adipose tissue was determined in 196 randomly selected, free-living, 40-49-year-old men in two regions of Finland (east and southwest) with a nearly twofold difference in the IHD rate.There were no significant east-southwest differences in platelet aggregation induced with ADP, thrombin or epinephrine. ADP-induced platelet secondary aggregation showed significant negative associations with all C20-C22 ω3-fatty acids in platelets (r = -0.26 - -0.40) and with the platelet 20: 5ω3/20: 4ω 6 and ω3/ ω6 ratios, but significant positive correlations with the contents of 18:2 in adipose tissue (r = 0.20) and plasma triglycerides (TG) (r = 0.29). Epinephrine-induced aggregation correlated negatively with 20: 5ω 3 in plasma cholesteryl esters (CE) (r = -0.23) and TG (r = -0.29), and positively with the total percentage of saturated fatty acids in platelets (r = 0.33), but had no significant correlations with any of the ω6-fatty acids. Thrombin-induced aggregation correlated negatively with the ω3/6ω ratio in adipose tissue (r = -0.25) and the 20: 3ω6/20: 4ω 6 ratio in plasma CE (r = -0.27) and free fatty acids (FFA) (r = -0.23), and positively with adipose tissue 18:2 (r = 0.23) and 20:4ω6 (r = 0.22) in plasma phospholipids (PL).The percentages of prostanoid precursors in platelet lipids, i. e. 20: 3ω 6, 20: 4ω 6 and 20 :5ω 3, correlated best with the same fatty acids in plasma CE (r = 0.32 - 0.77) and PL (r = 0.28 - 0.74). Platelet 20: 5ω 3 had highly significant negative correlations with the percentage of 18:2 in adipose tissue and all plasma lipid fractions (r = -0.35 - -0.44).These results suggest that, among a free-living population, relatively small changes in the fatty acid composition of plasma and platelets may be reflected in significant differences in platelet aggregation, and that an increase in linoleate-rich vegetable fat in the diet may not affect platelet function favourably unless it is accompanied by an adequate supply of ω3 fatty acids.

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