FATTY ACID SYNTHESIS IN NORMAL AND COLD-ACCLIMATED RATS

1964 ◽  
Vol 42 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Judith K. Patkin ◽  
E. J. Masoro
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
White Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Stomach Tube ◽  
Major Pathway

Rats acclimated to either 0–2 °C or 25 °C were given glucose-C14 via stomach tube and then sacrificed at [Formula: see text], 1, 6, or 24 hours. The cold-acclimated rats incorporated no more and possibly less C14 into fatty acids than did the rats acclimated to 25 °C. Evidence is presented which indicates that the white adipose tissue probably did not play a quantitatively important role in the conversion of the glucose-C14 to fatty acid. Also, the data indicate that lipogenesis was not a major pathway of the glucose-C14 metabolism.

Effects of pregnancy and ovarian steroids on fatty acid synthesis and uptake in Syrian hamsters

1991 ◽  
Vol 260 (1) ◽  
pp. R153-R158 ◽  
Author(s):  
A. J. Bhatia ◽  
G. N. Wade
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
White Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Ovarian Steroids ◽  
Syrian Hamsters

The effects of pregnancy and ovarian steroids on the in vivo distribution of newly synthesized fatty acids (incorporation of tritium from 3H2O into fatty acid) in Syrian hamsters (Mesocricetus auratus) were examined. During late, but not early, gestation hamsters had reduced levels of newly synthesized fatty acids in heart, liver, uterus, and white adipose tissues (parametrial and inguinal fat pads). Treatment of ovariectomized hamsters with estradiol + progesterone significantly decreased fatty acid synthesis-uptake in heart, liver, and inguinal white adipose tissue. Treatment with either estradiol or progesterone alone was without significant effect in any tissue. Pretreatment of hamsters with Triton WR-1339 (tyloxapol), an inhibitor of lipoprotein lipase activity and tissue triglyceride uptake, abolished the effects of estradiol + progesterone in white adipose tissue and heart but not in liver. Thus hamsters lose body fat during pregnancy in part because of decreased de novo lipogenesis. The effect of pregnancy on lipogenesis is mimicked by treatment with estradiol + progesterone but not by either hormone alone. Furthermore, it appears that the liver is the principal site of estradiol + progesterone action on lipogenesis in Syrian hamsters.

scholarly journals Important sites of lipogenesis in the mouse other than liver and white adipose tissue

1981 ◽  
Vol 196 (2) ◽  
pp. 645-647 ◽  
Author(s):  
Marjorie A. Hollands ◽  
M. A. Cawthorne
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
White Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Major Site

The musculature of the shoulders and back has been identified as a major site of fatty acid synthesis in mice.

The 1990 Borden Award Lecture Dietary regulation of fatty acid and triglyceride metabolism

1991 ◽  
Vol 69 (11) ◽  
pp. 1637-1647 ◽  
Author(s):  
Gene R. Herzberg
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Lipoprotein Lipase ◽  
Fatty Acid Synthesis ◽  
Dietary Fat ◽  
Acid Synthesis ◽  
Fish Oils ◽  
Dietary Fish

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.

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.

scholarly journals Utilization of methylmalonate for the synthesis of branched-chain fatty acids by preparations of chicken liver and sheep adipose tissue

1978 ◽  
Vol 176 (3) ◽  
pp. 799-804 ◽  
Author(s):  
J R Scaife ◽  
K W J Wahle ◽  
G A Garton
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Complex Mixture ◽  
Acid Synthesis ◽  
Inhibitory Effect ◽  
Chicken Liver ◽  
Malonyl Coa ◽  
Branched Chain

1. The utilization of methyl[2-14C]malonyl-CoA for fatty acid synthesis was investigated using synthetase preparations from chicken liver and sheep adipose tissue. 2. The rate of fatty acid synthesis from acetyl-CoA and malonyl-CoA was greatly diminished in the presence of methylmalonyl-CoA. 3. In the absence of malonyl-CoA, methylmalonyl-CoA was utilized for fatty acid synthesis only very slowly by the synthetase from sheep adipose tissue and not at all by that from chicken liver. 4. Despite the inhibitory effect of methylmalonyl-CoA on fatty acid synthesis from malonyl-CoA, it was utilized by the synthetase preparations from both species to produce a complex mixture of methyl-branched fatty acids.

scholarly journals Fatty acid synthesis in liver and adipose tissue of normal and genetically obese (ob/ob) mice during the 24-hour cycle

1975 ◽  
Vol 150 (2) ◽  
pp. 167-173 ◽  
Author(s):  
D A Hems ◽  
E A Rath ◽  
T R Verrinder
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Dark Period ◽  
Acid Synthesis ◽  
Obese Mice ◽  
Total Rate ◽  
Relative Significance ◽  
Adipose Organ

1. The synthesis of long-chain fatty acids de novo was measured in the liver and in regions of adipose tissue in intact normal and genetically obses mice throughout the daily 24h cycle. 2. The total rate of synthesis, as measured by the rate of incorporation of 3H from 3H2O into fatty acid, was highest during the dark period, in liver and adipose tissue of lean or obese mice. 3. The rate of incorporation of 14C from [U-14C]glucose into fatty acid was also followed (in the same mice). The 14C/3H ratios were higher by a factor of 5-20 in parametrial and scapular fat than that in liver. This difference was less marked during the dark period (of maximum fatty acid synthesis). 4. In normal mice, the total rate of fatty acid synthesis in the liver was about twofold greater than that in all adipose tissue regions combined. 5. In obese mice, the rate of fatty acid synthesis was more rapid than in lean mice, in both liver and adipose tissue. Most of the extra lipogenesis occurred in adipose tissue. The extra hepatic fatty acids synthesized in obese mice were located in triglyceride rather than phospholipid. 6. In adipose tissue of normal mice, the rate of fatty acid synthesis was most rapid in the intra-abdominal areas and in brown fat. In obese mice, all regions exhibited rapid rates of fatty acid synthesis. 7. These results shed light on the relative significance of liver and adipose tissue (i.e. the adipose ‘organ’) in fatty acid synthesis in mice, on the mino importance of glucose in hepatic lipogenesis, and on the alterations in the rate of fatty acid synthesis in genetically obese mice.

Studies on the Control of Fatty Acid Synthesis in White Adipose Tissue of the Rat: Effect of Alanine

1972 ◽  
Vol 50 (12) ◽  
pp. 1326-1333 ◽  
Author(s):  
Mitchell L. Halperin
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Redox Potential ◽  
White Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
High Flow ◽  
Flow Rates ◽  
Fatty Acid Synthesis Pathway ◽  
Tricarboxylate Carrier

(1) Alanine resulted in inhibition of lipogenesis in adipocytes from normal fed rats incubated with glucose and insulin.(2) Two related mechanisms are suggested for the lower rates of lipogenesis caused by alanine metabolism. (a) Lower pyruvate levels were seen in the presence of alanine. This could contribute to the observed inhibition as pyruvate is an intermediate in the fatty acid synthesis pathway. Pyruvate levels were probably lowered as a result of the increased cytosol redox potential produced by high flow rates through malate dehydrogenase in this compartment, (b) Inhibition could be a consequence of depletion of malate in the cytosol which could limit the mitochondrial tricarboxylate carrier associated with citrate entry into the cytosol.(3) TMPD, an agent which lowers cytoplasmic redox potential, increased both the malate and pyruvate levels and increased the lipogenic rates nearly to normal in the presence of alanine.

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