Regulation of hepatic lipogenesis by dietary maize oil or tripalmitin in the meal-fed mouse

The effect of varying dietary levels of maize oil and tripalmitin (0–250 g fat/kg) on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1.1.1.49; G6PD), malic enzyme (EC 1.1.1.38, 1.1.1.39, 1.1.1.40; ME) and glucokinase (EC 2.7.1.2; GK) was examined in meal-fed mice.2. Meal-fed mice compared to mice fed ad lib. show enhanced hepatic lipogenesis as demonstrated by an increased rate of in vivo fatty acid synthesis and increased levels of FAS, ME and G6PD. The level of GK in meal-fed mice was unchanged by meal feeding.3. Maize oil more effectively reduced in vivo hepatic lipogenesis than tripalmitin in meal-fed mice.4. Maize oil more effectively reduced the hepatic levels of FAS, G6PD, ME and GK than tripalmitin in meal-fed mice.5. The increased inhibition by maize oil is observed at all levels of fat in the diet investigated and has been shown not to be due to decreased carbohydrate intake nor to differences between the absorption of maize oil and tripalmitin.

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Hepatic lipogenesis in young rats given proteins of different quality

British Journal Of Nutrition ◽

10.1079/bjn19840079 ◽

1984 ◽

Vol 52 (1) ◽

pp. 131-137 ◽

Cited By ~ 11

Author(s):

G. R. Herzberg ◽

Minda Rogerson

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Protein Quality ◽

Fatty Acid Synthetase ◽

Acid Synthesis ◽

Hepatic Lipogenesis ◽

Atp Citrate Lyase ◽

Specific Activities ◽

Glucose 6 Phosphate Dehydrogenase

1. The effect of feeding casein, lactalbumin, soya-bean protein, gluten or gelatin on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1. 1. 1.49; G6PD), malic enzyme (EC 1. 1. 1.40; ME) ATP-citrate lyase (EC 4. 1. 3. 8; CL), acetyl CoA carboxylase (EC 6.4.1.2; ACCx) and glucokinase (EC 2. 7. 1. 2; GK) was examined in young growing rats.2. The total activities of ACCx, FAS, CL, GK, G6PD, GK, ME and fatty acid synthesis in vivo were positively correlated with protein quality.3. The specific activities of ACCx, FAS, CL, G6PD and fatty acid synthesis in vivo were positively correlated with protein quality.4. The specific activities of GK and ME were unrelated to protein quality.5. The results demonstrate a dissociation between ME and hepatic lipogenesis and suggest a role for the NADPH generated by ME which is not related to the needs of fatty acid synthesis.

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The role of dietary protein in hepatic lipogenesis in the young rat

British Journal Of Nutrition ◽

10.1079/bjn19810131 ◽

1981 ◽

Vol 45 (3) ◽

pp. 529-538 ◽

Cited By ~ 14

Author(s):

G. R. Herzberg ◽

Minda Rogerson

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Dietary Protein ◽

Fatty Acid Synthetase ◽

Acid Synthesis ◽

Hepatic Lipogenesis ◽

Hepatic Fatty Acid ◽

Cleavage Enzyme ◽

Glucose 6 Phosphate Dehydrogenase

1. The effect of varying dietary levels of casein (40–140 g/kg) on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1.1.1.49; G6PD), malic enzyme (EC 1.1.1.40; ME), citrate cleavage enzyme (EC 4.1.3.8;CCE), acetyl CoA carboxylase (EC 6.4.1.2; AcCx), glucokinase (EC 2.7.1.2; GK), and pyruvate dehydrogenase (PDH) was examined in young, growing rats.2. The activities of AcCx, FAS, G6PD and in vivo fatty acid synthesis were generally found to increase with increased dietary protein.3. The levels of GK and PDH were not related to dietary protein.4. ME decreased with increasing dietary protein.5. The results demonstrate a dissociation between hepatic fatty acid synthesis and ME and suggest that when rats consume low-protein diets the NADPH needed for fatty acid synthesis is generated primarily by ME but that as the level of dietary protein is increased the contribution of ME is reduced while that of the phosphogluconate pathway becomes more important.

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Fatty acid elongation by a particulate fraction from germinating pea

Biochemical Journal ◽

10.1042/bj1910791 ◽

1980 ◽

Vol 191 (3) ◽

pp. 791-797 ◽

Cited By ~ 13

Author(s):

B R Jordan ◽

J L Harwood

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Fatty Acid Synthesis ◽

High Speed ◽

Saturated Fatty Acids ◽

Acyl Chain ◽

Fatty Acid Synthetase ◽

Acid Synthesis ◽

Particulate Fraction

The synthesis of fatty acids from [14C]malonyl-CoA was studied with a high-speed particulate fraction from germinating pea (Pisum sativum). The variety used (Feltham First) produced mainly saturated fatty acids with palmitate (30–40%) and stearate (40–60%) predominating. Several palmitate-containing lipids stimulated overall synthesis and, in addition, increased the percentage of label in stearate. The production of stearate was severely inhibited by preincubation of the microsomal fraction with snake venom phospholipase A2 or by incubation with Rhizopus arrhizus lipase. Addition of a series of di-saturated phosphatidylcholines, with different acyl constituents, resulted in stimulation of overall fatty acid synthesis as well as an increase in the radiolabelling of the fatty acid two carbon atoms longer than the acyl chain added. This chain lengthening of fatty acids donated from phosphatidylcholine was due to the action of both fatty acid synthetase and palmitate elongase. The latter would utilize dipalmitoyl phosphatidylcholine and was sensitive to arsenite whereas fatty acid synthetase would use dilauroyl phosphatidylcholine and was sensitive to cerulenin. The results are discussed in relation to previous data obtained in vivo on plant fatty acid synthesis and current suggestions for the role of phosphatidylcholine in this process.

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Effect of prolonged ethanol ingestion on hepatic lipogenesis and related enzyme activities

Biochemical Journal ◽

10.1042/bj1640169 ◽

1977 ◽

Vol 164 (1) ◽

pp. 169-177 ◽

Cited By ~ 31

Author(s):

Markku J. Savolainen ◽

J. Kalervo Hiltunen ◽

Ilmo E. Hassinen

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Control Diet ◽

Active Form ◽

Acid Synthesis ◽

Ethanol Ingestion ◽

Synthetase Activity ◽

Hepatic Lipogenesis ◽

Triacylglycerol Accumulation

1. Hepatic lipogenesis in vivo and the activities of enzymes associated with fatty acid synthesis in the liver were studied in rats fed for 21 days on liquid diets containing ethanol. 2. The ethanol-fed rats developed a moderate hepatic triacylglycerol accumulation during this period. When carbohydrate was replaced by ethanol in the diet, the rate of fatty acid synthesis was slower in the ethanol-fed rats on low-, medium- and high-fat diets than in the appropriate controls. However, when the fat/carbohydrate ratio was kept the same in the ethanol-fed and control rats, ethanol had no influence on the rate of fatty acid synthesis. 3. Glucose 6-phosphate dehydrogenase activity was lower in the ethanol-fed group. ‘Malic’ enzyme activity did not change during the ethanol treatment when the fat/carbohydrate ratio was kept unchanged. 4. The ATP citrate lyase activity was lower in the ethanol-fed rats on all diets, whereas acetyl-CoA synthetase activity was independent of the composition of the control diet, but was lower in the ethanol-fed rats, in which the concentration of the active form of pyruvate dehydrogenase was also lower. 5. It is concluded that hepatic fatty acid synthesis does not play any major role in ethanol-induced triacylglycerol accumulation. Careful design of the diets is necessary to reveal the specific effects of ethanol on the enzymes associated with lipogenesis.

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The effects of dietary fat on fatty acid synthesis and malic enzyme activity in liver from growing chicks

Canadian Journal of Biochemistry ◽

10.1139/o69-112 ◽

1969 ◽

Vol 47 (7) ◽

pp. 743-746 ◽

Cited By ~ 11

Author(s):

Alan G. Goodridge

Keyword(s):

Fatty Acids ◽

Enzyme Activity ◽

Fatty Acid ◽

Fatty Acid Synthesis ◽

Dietary Fat ◽

Malic Enzyme ◽

Corn Oil ◽

Acid Synthesis ◽

Hepatic Lipogenesis ◽

Malic Enzyme Activity

Hepatic malic enzyme activity and incorporation of glucose-U-14C into fatty acids in liver slices was no greater in birds fed fat-free diets than in those fed the same diets supplemented with corn oil. The results suggest that in the chick, in contrast to the rat, dietary fat does not suppress hepatic lipogenesis.

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Ethanol administration and the relationship of malonyl-coenzyme A concentrations to the rate of fatty acid synthesis in rat liver

Biochemical Journal ◽

10.1042/bj1360639 ◽

1973 ◽

Vol 136 (3) ◽

pp. 639-647 ◽

Cited By ~ 26

Author(s):

Robert W. Guynn ◽

Dulce Veloso ◽

Raymond L. Harris ◽

J. W. Randolph Lawson ◽

Richard L. Veech

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

De Novo ◽

Fatty Acid Synthetase ◽

Acid Synthesis ◽

Ethanol Administration ◽

Liver Fatty Acid ◽

Malonyl Coa ◽

Significant Difference

1. The effect of ethanol on liver fatty acid synthesis was studied in vivo in 24h-starved and ‘meal-fed’ rats (i.e. fed for 3h per day and not ad libitum). 2. In the fed animal3H2O was incorporated into fat at a rate of 0.46μmol of C2 units/min per g wet wt. of liver. Administration of either ethanol (3.2g/kg) or equicaloric amounts of glucose had no effect on the rate of3H2O incorporation into lipid. 3. In the 24h-starved animal, administration of the same dose of ethanol produced an increase in the rate of3H2O incorporation from 0.06 to 0.12μmol of C2 units/min per g fresh wt. after 3h whereas [malonyl-CoA] increased from 0.006 to 0.009μmol/g. Glucose given in amounts equicaloric to ethanol was significantly more lipogenic, increasing both the3H2O incorporation from 0.06 to 0.20μmol of C2 units/min per g and the malonyl-CoA content from 0.006 to 0.013 μmol/g wet wt. at 3h. 4. The decrease in the redox state of free cytoplasm NAD or NADP couples or the changes in content of citrate, glucose 6-phosphate and pyruvate of liver after ethanol administration had no measurable effect on the rate of fatty acid synthesis in vivo. 5. Under the conditions of the experiments there was no significant difference, among any of the groups, in the activity of liver fatty acid synthetase measured in vitro. A double-reciprocal plot of the rate of3H2O incorporation and the total tissue malonyl-CoA concentrations showed a striking relationship. It has been concluded that the rate of fatty acid synthesis in vivo is determined principally by the Vmax. of fatty acid synthetase and the concentration of free malonyl-CoA. 6. It has also been concluded that under the conditions of the present study, the synthesis of fatty acids de novo is unlikely to be an important factor in the increased liver lipid content associated with ethanol administration.

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Effect of (—)-Hydroxycitrate on Fatty Acid Synthesis by Rat Liver in Vivo

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)62460-3 ◽

1971 ◽

Vol 246 (3) ◽

pp. 629-632

Author(s):

John M. Lowenstein

Keyword(s):

Fatty Acid ◽

Rat Liver ◽

Fatty Acid Synthesis ◽

Acid Synthesis

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Modulation of lipid-synthesizing enzymes by insulin in differentiated ob17 adipose-like cells

Biochemical Journal ◽

10.1042/bj2140443 ◽

1983 ◽

Vol 214 (2) ◽

pp. 443-449 ◽

Cited By ~ 15

Author(s):

P Grimaldi ◽

C Forest ◽

P Poli ◽

R Negrel ◽

G Ailhaud

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Specific Activity ◽

Fatty Acid Synthetase ◽

Lipid Synthesis ◽

Acid Synthesis ◽

Acetate Incorporation ◽

Long Term Effects ◽

Response Curves ◽

Glycerol 3 Phosphate Dehydrogenase

ob17 cells convert into adipose-like cells when maintained in the presence of physiological concentrations of insulin and tri-iodothyronine. After this conversion, insulin removal from differentiated ob17 cells gives within 24-48 h a large decrease in fatty acid synthetase, glycerol 3-phosphate dehydrogenase and acid:CoA ligase activities, as well as in the rate of fatty acid synthesis determined by [14C]acetate incorporation into lipids. All parameters are restored by insulin addition to initial values within 24-48 h. Dose-response curves of insulin on the restoration of glycerol 3-phosphate dehydrogenase activity and of fatty acid synthesis give half-maximally effective concentrations close to 1 nM, in agreement with the affinity for insulin of the insulin receptors previously characterized in these cells. Immunotitration experiments indicate that the changes in the specific activity of fatty acid synthetase are due to parallel changes in the cellular enzyme content. Therefore the ob17 cell line should be a useful model to study the long-term effects of insulin on the modulation of lipid synthesis in adipose cells.

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