THE EFFECT OF VARIOUS SACCHARIDES ON THE RELEASE OF NON ESTERIFIED FATTY ACIDS FROM ADIPOSE TISSUE IN VITRO

1962 ◽  
Vol 40 (4) ◽  
pp. 455-458 ◽  
Author(s):  
W. F. Perry ◽  
R. J. Tjaden
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Incubation Medium ◽  
Epididymal Adipose Tissue ◽  
Tissue Cell ◽  
Glycerol Phosphate ◽  
Esterified Fatty Acids ◽  
Adipose Tissue Cell ◽  
Other Substances

Rat epididymal adipose tissue was incubated in a phosphate–albumin medium to ascertain the effect of various saccharides and other substances on the release of non-esterified fatty acids (NEFA) into the medium. It was found that incubation with glucose, mannose, fructose, and 2-deoxy glucose resulted in less release of NEFA from the tissue into the incubation medium. Incubation with galactose, sucrose, lactose, D-ribose, D-xylose, L-xylose, D-arabinose, L-arabinose, D-lyxose, sodium pyruvate, glycerol, and glycerol phosphate showed no differences from the control in release of NEFA into the incubation medium. These results are consistent with the theory that the NEFA-lowering action of glucose is due to esterification of free fatty acid within the adipose tissue cell by glycerol phosphate.

THE EFFECT OF VARIOUS SACCHARIDES ON THE RELEASE OF NON ESTERIFIED FATTY ACIDS FROM ADIPOSE TISSUE IN VITRO

1962 ◽  
Vol 40 (1) ◽  
pp. 455-458
Author(s):  
W. F. Perry ◽  
R. J. Tjaden
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Incubation Medium ◽  
Epididymal Adipose Tissue ◽  
Tissue Cell ◽  
Glycerol Phosphate ◽  
Esterified Fatty Acids ◽  
Adipose Tissue Cell ◽  
Other Substances

Rat epididymal adipose tissue was incubated in a phosphate–albumin medium to ascertain the effect of various saccharides and other substances on the release of non-esterified fatty acids (NEFA) into the medium. It was found that incubation with glucose, mannose, fructose, and 2-deoxy glucose resulted in less release of NEFA from the tissue into the incubation medium. Incubation with galactose, sucrose, lactose, D-ribose, D-xylose, L-xylose, D-arabinose, L-arabinose, D-lyxose, sodium pyruvate, glycerol, and glycerol phosphate showed no differences from the control in release of NEFA into the incubation medium. These results are consistent with the theory that the NEFA-lowering action of glucose is due to esterification of free fatty acid within the adipose tissue cell by glycerol phosphate.

THE EFFECT OF HOMOGENIZATION ON FREE AND ESTERIFIED FATTY ACID POOLS IN ADIPOSE TISSUE

1965 ◽  
Vol 43 (2) ◽  
pp. 271-280 ◽  
Author(s):  
David Rubinstein ◽  
Anna M. Daniel ◽  
Sylvester Chiu ◽  
John C. Beck
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Incubation Medium ◽  
Specific Activity ◽  
Tissue Cell ◽  
Intact Tissue ◽  
Adipose Tissue Cell ◽  
Specific Activities ◽  
Presence And Absence

The effect of homogenization of adipose tissue on fatty acid pools was studied with palmitate-1-C14 in the presence and absence of epinephrine. Addition of epinephrine to intact tissue in an incubation medium high in FFA increases the specific activity of the tissue FFA. When the tissue is incubated in a medium low in FFA, epinephrine induces an increase in the concentration and radioactivity of the tissue FFA. Epinephrine decreases the esterification of palmitate-1-C14 by intact tissue, regardless of the FFA concentration in the medium. This decrease is unrelated to the specific activities of either the medium or the tissue FFA. In homogenates, the decrease in incorporation of palmitate-1-C14 is proportional to the decrease in the specific activity of the FFA induced by epinephrine. Under the influence of epinephrine, FFA released from adipose tissue that was previously charged with palmitate-1-C14 have a specific activity about six times as great as the glyceride fatty acids. This difference is abolished by homogenization of the tissue. These results suggest that the newly synthesized triglycerides exist as a separate pool and are more readily hydrolyzed, thereby contributing FFA to an intracellular FFA pool. The existence of multiple pools of glycerides and FFA in the adipose tissue cell is dependent on the architecture of the cell.

FREE FATTY ACID METABOLISM IN CHINESE HAMSTERS

1966 ◽  
Vol 44 (1) ◽  
pp. 47-57 ◽  
Author(s):  
James Campbell ◽  
G. R. Green
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Spontaneous Diabetes ◽  
Chinese Hamster ◽  
Diabetic Rats ◽  
Epididymal Adipose Tissue ◽  
Time Interval ◽  
Adipose Tissues ◽  
Chinese Hamsters

In normal Chinese hamsters (Cricetulus griseus) the mean concentration of free fatty acids (FFA) in serum varied from group to group, but was (i) consistently 4 to 9 times greater than in rats, dogs, or man; (ii) slightly higher than in Syrian hamsters; (iii) two- to four-fold higher than in fasting or alloxan-diabetic rats. The epididymal adipose tissue of the Chinese hamster (i) had initial concentrations of FFA comparable to those in the rat and Syrian hamster; (ii) released, in the same time interval, 8- to 10-fold more FFA in vitro than this tissue of the rat; (iii) had higher concentrations of FFA after incubation than the incubated tissue of the rat. The retroperitoneal (perirenal) adipose tissue of the Chinese hamster was less active in release of fatty acids in vitro than the epididymal, but was, however, more active than the epididymal adipose tissue of the rat. These characteristics of FFA metabolism in the Chinese hamster were apparently attributable to species, not to age, diet, or sex. In the Chinese hamster, the weight of the epididymal adipose tissue per gram of body was relatively high. It appears that in this species the rate of release of fatty acids from adipose tissue is great, leading to high FFA concentrations in serum.In Chinese hamster and rat adipose tissues in vitro, glucose and insulin (separately) reduced the rate of release of FFA and the amount of FFA in the tissues, but glucose and insulin together produced the greatest reductions. The net reduction in FFA release by glucose and insulin in vitro was greater in tissue from the Chinese hamster. Insulin markedly increased glucose uptake by the adipose tissues of both species. The possible relation of the results to spontaneous diabetes in the Chinese hamster is discussed.

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.

THE IN VITRO UTILIZATION AND PRODUCTION OF NON-ESTERIFIED FATTY ACIDS BY ADRENALECTOMIZED RATS

1961 ◽  
Vol 39 (6) ◽  
pp. 1061-1065 ◽  
Author(s):  
W. F. Perry ◽  
Helen F. Bowen
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Liver Tissue ◽  
In Vitro Production ◽  
Esterified Fatty Acids ◽  
Adrenalectomized Animal ◽  
Vitro Production ◽  
Adrenalectomized Rats

The in vitro utilization of non-esterified fatty acids by various tissues and the in vitro production of non-esterified fatty acids by adipose tissue have been compared in normal and adrenalectomized rats. It was found that the production of NEFA by adipose tissue was similar in both groups of animals but that the in vitro utilization of NEFA and production of carbon dioxide by heart, diaphragm, kidney, and liver tissue was greater in the adrenalectomized animal. These findings together with the depletion of fat content of the depots are interpreted as indicating that in the adrenalectomized state there is increased peripheral utilization of fatty acids.

An additional role for insulin in the control of fatty acid synthesis independent of glucose transport

1970 ◽  
Vol 48 (11) ◽  
pp. 1228-1233 ◽  
Author(s):  
M. L. Halperin
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Glucose Transport ◽  
Fatty Acid Synthesis ◽  
Incubation Medium ◽  
Fold Increase ◽  
Acid Synthesis ◽  
Epididymal Adipose Tissue ◽  
Exogenous Substrate

Glucose conversion into pyruvate and fatty acids was studied in epididymal adipose tissue incubated in vitro from normal, 36-h-fasted and fasted–refed rats.Insulin at optimal concentrations caused a 30-fold increase in the rate of glucose incorporation into fatty acids and an increased lactate/pyruvate output rate. Pyruvate, lactate, and N,N,N′,N′,-tetramethyl-p-phenylenediamine (TMPD) addition to this incubation medium resulted in a further 20–75% increase in the rate of fatty acid synthesis as well as a further increase in the pyruvate concentration of the incubation medium. These results suggested that it was the decreased pyruvate concentration secondary to the elevated NADH/NAD+ of the cytoplasm which limited further glucose conversion to fatty acid.With glucose as substrate, TMPD caused the medium pyruvate concentration to be at least as high or higher than that seen with insulin in both nutritional states. However, fatty acid synthesis rates were eightfold greater with insulin. Insulin in the absence of glucose caused a twofold increase in the fatty acid synthesis from pyruvate at a medium concentration of 250 μM in normal and 25 mM in the 36-h-fasted rat. Therefore, insulin augments the rate of fatty acid synthesis both by increasing the supply of substrate (pyruvate) and also by directly increasing pyruvate incorporation into fatty acid by a mechanism distinct from the known stimulation of glucose transport.In fat pads from fasted–refed rats incubated in the absence of exogenous substrate, the rate of fatty acid synthesis was doubled by insulin. This occurred when the rate of pyruvate output was half that in the control condition. This also suggests that insulin stimulated pyruvate conversion to fatty acid in the absence of the known augmentation of glucose transport by insulin.

ESTERIFICATION OF INTRA- AND EXTRA-CELLULAR FREE FATTY ACIDS BY RAT ADIPOSE TISSUE

1965 ◽  
Vol 43 (6) ◽  
pp. 635-645 ◽  
Author(s):  
David Rubinstein ◽  
Anna M. Daniel ◽  
Lydia Lechter ◽  
John C. Beck
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Incubation Medium ◽  
Neutral Lipids ◽  
Long Chain Fatty Acids ◽  
Adipose Tissue In Vitro ◽  
Rat Adipose Tissue ◽  
Glycerol Esterification ◽  
Long Chain

The esterification of intracellular and extracellular FFA by rat adipose tissue in vitro was investigated. The rate of incorporation of FFA into neutral lipids was proportional to the FFA concentration in the incubation medium. Both in the presence and absence of a lipolytic agent (epinephrine), heptadecanoate-1-C14, which is not specifically diluted by tissue fatty acids, was esterified in the same manner as palmitate-9,10-H3. Stearate, palmitate, and oleate were esterified at similar rates by adipose tissue taken from fed animals and incubated with glucose. The rate of esterification of one fatty acid was not significantly affected by the presence of another. Similar results were obtained when tissues were taken from fasted animals and incubated in the absence of glucose, except that the overall rate of esterification was diminished and FFA accumulated in the tissue. It is concluded that long-chain fatty acids do not compete for esterification or entry into the adipose tissue cell.In some experiments tissue FFA esterification was studied by measuring the incorporation of glucose-U-C14 carbons into glyceride–glycerol. Esterification, assayed in this manner, increased when albumin was present in the incubation medium and allowed FFA to diffuse from the tissue. However, pre-incubation of adipose tissue in medium containing labelled FFA indicates that much of the intracellular FFA may be esterified without its mixing with the extracellular FFA pool.

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