scholarly journals Aspects of adipose-tissue metabolism in foetal lambs

1981 ◽  
Vol 196 (3) ◽  
pp. 819-824 ◽  
Author(s):  
R G Vernon ◽  
J P Robertson ◽  
R A Clegg ◽  
D J Flint

1. The mean volume of adipocytes, the rates of fatty acid and acylglycerol glycerol synthesis from various precursors (in vitro), the rates of oxidation of acetate and glucose (in vitro) and the activities of lipoprotein lipase and various lipogenic enzymes were determined for perirenal adipose tissue from foetal lambs during the last month of gestation. 2. The fall in the rate of growth of perirenal adipose tissue during the last month of gestation is associated with a diminished capacity for fatty acid synthesis and lipoprotein lipase activity, but no change in the rate of acylglycerol glycerol synthesis was observed. There was no fall in the activities of cytosolic acetyl-CoA synthetase or the NADP-linked dehydrogenases, suggesting that the decrease in the rate of fatty acid synthesis was due to an impairment at the level of acetyl-CoA carboxylase or fatty acid synthetase. 3. The rate of fatty acid synthesis from acetate was greater than that from glucose. The rate of fatty acid synthesis from glucose per adipocyte of foetal lambs was similar to that of young sheep. The characteristic metabolism of adipose tissue of the adult sheep is thus present in the foetus, despite the relatively large amounts of glucose in the foetal ‘diet’.

1988 ◽  
Vol 251 (2) ◽  
pp. 547-551 ◽  
Author(s):  
J S Wilson ◽  
M A Korsten ◽  
L P Donnelly ◽  
P W Colley ◽  
J B Somer ◽  
...  

Administration of ethanol as part of a nutritionally adequate liquid diet to female Wistar rats was found to depress markedly incorporation of labelled glucose into adipose-tissue acylglycerol fatty acids. Similar results with labelled pyruvate and acetate suggested inhibition of the fatty-acid-synthesis pathway at, or distal to, the acetyl-CoA carboxylase step. Activities of acetyl-CoA carboxylase and fatty acid synthetase were markedly lower in ethanol-fed animals. The activity of another lipogenic enzyme, phosphatidate phosphohydrolase, was not affected by chronic ethanol feeding. These findings suggest that chronic ethanol administration has marked effects on adipose-tissue lipogenesis.


1988 ◽  
Vol 47 (2) ◽  
pp. 263-270 ◽  
Author(s):  
P. A. Sinnett-Smith ◽  
J. A. Woolliams

ABSTRACTAdipocyte volume rates of fatty acid synthesis, acylglycerol glycerol synthesis and lipolysis (basal and noradrenaline stimulated) along with the activities of acetyl CoA carboxylase and lipoprotein lipase were determined in subcutaneous adipose tissue, sampled by biopsy, from the rump of four breeds of sheep differing in growth and body characteristics.Significant differences among breeds were observed for adipocyte volume, fatty acid synthesis, stimulated lipolysis rates, initial and total acetyl CoA carboxylase activity and lipoprotein lipase activity, but not for acylglycerol glycerol synthesis.Differences in adipocyte volume did not appear to be related to the previously reported carcass fatnesses of the breeds. Similarly differences in adipocyte volume were not related to differences in either de novo fatty acid synthesis or lipolysis rates. Across breeds there was a trend toward higher acylglycerol glycerol synthesis rates associated with greater adipocyte volume although the source of fatty acids for esterification varied greatly.Breed variation in fatness in sheep therefore appears to be a consequence of different balances of anabolic and catabolic processes in adipose tissue, with a unique pattern for each breed. Further elucidation of these patterns may lead to the identification of key sites for genetic manipulation. In addition these breed differences provide an alternative, complementary and qualitatively different, model for the study of the control of fat metabolism to that provided by nutritional or hormonal manipulations.


1959 ◽  
Vol 234 (12) ◽  
pp. 3111-3114 ◽  
Author(s):  
Albert I. Winegrad ◽  
Walter N. Shaw ◽  
Francis D.W. Lukens ◽  
William C. Stadie

1987 ◽  
Vol 243 (2) ◽  
pp. 437-442 ◽  
Author(s):  
M G Buckley ◽  
E A Rath

1. The effect of nutritional status on fatty acid synthesis in brown adipose tissue was compared with the effect of cold-exposure. Fatty acid synthesis was measured in vivo by 3H2O incorporation into tissue lipids. The activities of acetyl-CoA carboxylase and fatty acid synthetase and the tissue concentrations of malonyl-CoA and citrate were assayed. 2. In brown adipose tissue of control mice, the tissue content of malonyl-CoA was 13 nmol/g wet wt., higher than values reported in other tissues. From the total tissue water content, the minimum possible concentration was estimated to be 30 microM 3. There were parallel changes in fatty acid synthesis, malonyl-CoA content and acetyl-CoA carboxylase activity in response to starvation and re-feeding. 4. There was no correlation between measured rates of fatty acid synthesis and malonyl-CoA content and acetyl-CoA carboxylase activity in acute cold-exposure. The results suggest there is simultaneous fatty acid synthesis and oxidation in brown adipose tissue of cold-exposed mice. This is probably effected not by decreases in the malonyl-CoA content, but by increases in the concentration of free long-chain fatty acyl-CoA or enhanced peroxisomal oxidation, allowing shorter-chain fatty acids to enter the mitochondria independent of carnitine acyltransferase (overt form) activity.


1991 ◽  
Vol 69 (11) ◽  
pp. 1637-1647 ◽  
Author(s):  
Gene R. Herzberg

The level of circulating triacylglycerols is determined by the balance between their delivery into the plasma and their removal from it. Plasma triacylglycerols are derived either from dietary fat as chylomicrons or from endogenous hepatic synthesis as very low density lipoproteins. Their removal occurs through the action of lipoprotein lipase after which the fatty acids are either stored in adipose tissue or oxidized, primarily in skeletal muscle and heart. The composition of the diet has been shown to influence many of these processes. Hepatic fatty acid synthesis and triacylglycerol secretion are affected by the quantity and composition of dietary fat, carbohydrate, and protein. Polyunsaturated but not saturated fats reduce hepatic fatty acid synthesis by decreasing the amount of the lipogenic enzymes needed for de novo fatty acid synthesis. Dietary fish oils are particularly effective at reducing both fatty acid synthesis and triacylglycerol secretion and as a result are hypotriacylglycerolemic, particularly in hypertriacylglycerolemic individuals. In addition, dietary fish oils can increase the oxidation of fatty acids and lead to increased activity of lipoprotein lipase in skeletal muscle and heart. It appears that the hypotriacylglycerolemic effect of dietary fish oils is mediated by effects on both synthesis and removal of circulating triacylglycerols.Key words: lipid, fish oil, fructose, liver, adipose tissue, oxidation.


2013 ◽  
Vol 57 (11) ◽  
pp. 5729-5732 ◽  
Author(s):  
Joshua B. Parsons ◽  
Matthew W. Frank ◽  
Jason W. Rosch ◽  
Charles O. Rock

ABSTRACTInactivation of acetyl-coenzyme A (acetyl-CoA) carboxylase confers resistance to fatty acid synthesis inhibitors inStaphylococcus aureuson media supplemented with fatty acids. The addition ofanteiso-fatty acids (1 mM) plus lipoic acid supports normal growth of ΔaccDstrains, but supplementation with mammalian fatty acids was less efficient. Mice infected with strain RN6930 developed bacteremia, but bacteria were not detected in mice infected with its ΔaccDderivative.S. aureusbacteria lacking acetyl-CoA carboxylase can be propagatedin vitrobut were unable to proliferate in mice, suggesting that the acquisition of inactivating mutations in this enzyme is not a mechanism for the evasion of fatty acid synthesis inhibitors.


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