scholarly journals Studies in lipogenesis in vivo. Fatty acid and cholesterol synthesis during starvation and re-feeding

1966 ◽  
Vol 101 (3) ◽  
pp. 811-818 ◽  
Author(s):  
GR Jansen ◽  
ME Zanetti ◽  
CF Hutchison
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Intraperitoneal Injection ◽  
Cholesterol Synthesis ◽  
Liver Glycogen ◽  
Acid Synthesis ◽  
Tracer Dose ◽  
Intraperitoneal Dose

1. Lipogenesis in vivo has been studied in mice given a 250mg. meal of [U-(14)C]glucose (2.5muc) or given an intraperitoneal injection of 25mug. of [U-(14)C]glucose (2.0muc). 2. The ability to convert a [U-(14)C]glucose meal into fatty acid was not significantly depressed by 6-7hr. of starvation. In contrast, incorporation of (14)C into fatty acid in the liver after the intraperitoneal dose of [(14)C]glucose was depressed by 80% and by more than 90% by 1 and 2hr. of starvation respectively. Carcass fatty acid synthesis from the [U-(14)C]glucose meal was not depressed by 12hr. of starvation, whereas from the tracer dose of [U-(14)C]glucose the depression in incorporation was 80% after 6hr. of starvation. 3. Re-feeding for 3 days, after 3 days' starvation, raised fatty acid synthesis and cholesterol synthesis in the liver fivefold and tenfold respectively above the levels in non-starved control mice. These increases were associated with an increased amount of both fatty acid and cholesterol in the liver. 4. After 18hr. of starvation incorporation of a [U-(14)C]glucose meal into carcass and liver glycogen were both increased threefold.

scholarly journals Effect of propionate on fatty acid and cholesterol synthesis and on acetate metabolism in isolated rat hepatocytes

1995 ◽  
Vol 74 (2) ◽  
pp. 209-219 ◽  
Author(s):  
Christian Demigné ◽  
Christine Morand ◽  
Marie-Anne Levrat ◽  
Catherine Besson ◽  
Corinne Moundras ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Cholesterol Synthesis ◽  
Rat Hepatocytes ◽  
Acid Synthesis ◽  
High Rate ◽  
Acetate Metabolism ◽  
Effective Inhibitor ◽  
Isolated Rat Hepatocytes

In the present study the actual role of propionic acid in the control of fatty acid and cholesterol synthesis was investigated in isolated liver cells from fed rats maintained in the presence of near-physiological concentrations of glucose, glutamine and acetate. Using 3H2O for lipid labelling, propionate appears as an effective inhibitor of fatty acid synthesis and to a lesser extent of cholesterol synthesis, even at the lowest concentration used (0·6 mmol/l). Butyrate is a potent activator of both synthetic pathways, and the activating effect was not counteracted by propionate. Using 1-[14C]acetate, it was observed that propionate at a moderate concentration, or 1 mmol oleate/l, are both very effective inhibitors of 14C incorporation into fatty acid and cholesterol. This incorporation was drastically inhibited when propionate and oleate were present together in the incubation medium. The net utilization of acetate by rat hepatocytes was impaired by propionate, in contrast to oleate. 1-[14C]butyrate was utilized at a high rate for fatty acid synthesis, but to a lesser extent for cholesterol synthesis; both processes were unaffected by propionate. Intracellular citrate concentration was not markedly depressed by propionate, whereas it was strongly elevated by butyrate. In conclusion, propionate may represent an effective inhibitor of lipid synthesis when acetate is a major source of acetyl-CoA, a situation which is encountered with diets rich in readily-fermentable fibres. The present findings also suggest that propionate may be effective at concentrations close to values measured in vivo in the portal vein.

EFFECT OF ALLOXAN, INSULIN, AND THYROXINE ON CHOLESTEROL AND FATTY ACID SYNTHESIS BY RAT LIVER HOMOGENATES

1957 ◽  
Vol 35 (1) ◽  
pp. 15-23 ◽  
Author(s):  
J. F. Scaife ◽  
B. B. Migicovsky
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Fatty Acid Synthesis ◽  
Sodium Acetate ◽  
Cholesterol Synthesis ◽  
Acid Synthesis ◽  
Liver Homogenates ◽  
Vitro Effect

The in vitro effect of alloxan and insulin on the synthesis of cholesterol and fatty acids from 1-C14-sodium acetate by rat liver homogenates has been examined. Alloxan caused a reduction in the incorporation of acetate into cholesterol, fatty acids, and C14O2, but an increase in the oxygen consumption and carbon dioxide production. The addition of insulin to homogenates caused a reduction in cholesterol synthesis but an increase in fatty acid synthesis both for normal and diabetic animals. Homogenates from thyrotoxic rats exhibited a marked reduction in cholesterol synthesis when compared with normal animals. C14O2 production by homogenates from starved rats was appreciably lower than for those from normal animals. With this exception no appreciable difference was found in the oxygen uptake, carbon dioxide, or C14O2 production in homogenates from normal, starved, thyroxine-treated, or diabetic animals. Synthesized cholesterol was found to be located principally in the particulate matter of the homogenates after they had been incubated with 1-C14-sodium acetate. Homogenates from starved rats showed no greater tendency to degrade preformed cholesterol during incubation than did those from normal rats.

Lipogenesis in the Ruminant: in vivo Site of Fatty Acid Synthesis in Sheep

1972 ◽  
Vol 102 (5) ◽  
pp. 617-623 ◽  
Author(s):  
D. L. Ingle ◽  
D. E. Bauman ◽  
U. S. Garrigus
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis

Understanding in vivo carbon precursor supply for fatty acid synthesis in leaf tissue

2000 ◽  
Vol 22 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Xiaoming Bao ◽  
Manfred Focke ◽  
Mike Pollard ◽  
John Ohlrogge
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Leaf Tissue ◽  
Acid Synthesis ◽  
Carbon Precursor ◽  
Precursor Supply

In vivo and in vitro lipogenesis and aspects of metabolism in ovines: Effect of environmental temperature and dietary lipid supplementation

2000 ◽  
Vol 80 (1) ◽  
pp. 59-67 ◽  
Author(s):  
J. A. Moibi ◽  
R. J. Christopherson ◽  
E. K. Okine
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Cold Exposure ◽  
Average Daily Gain ◽  
Acid Synthesis ◽  
Dietary Lipid ◽  
Acetate Incorporation ◽  
Lipid Supplementation

Twenty-four wether lambs were randomly allocated to six treatments to investigate the effect of temperature and dietary lipid supplements on fatty acid synthesis and metabolic activity in sheep. The treatments consisted of four groups exposed to either cold (0 °C) or warm temperature (+23 °C) and given ad libitum access to either a control barley-based diet or with lipid supplementation. Two other groups were placed on the dietary regimen at 0 °C, but pair-fed to intake of animals in the +23 °C environment. At 5 wk, fatty acid synthesis was measured by [1-14C]acetate incorporation into tissue lipids. Cold exposure and dietary lipid supplementation had no effect (P > 0.05) on in vivo fatty acid synthesis rates in either longissimus dorsi or the liver. In both subcutaneous and mesenteric adipose tissue depots, the rate of acetate incorporation into tissue lipid was not significantly affected by cold exposure. In the perirenal fat depot, cold exposure increased (P < 0.05) the rate of fatty acid synthesis, while lipid supplementation decreased (P < 0.05) the rate in all tissue adipose depots. In vitro, mesenteric and perirenal adipose tissues from cold pair-fed animals had higher (P < 0.05) rates of fatty acid synthesis compared to tissues from animals in the warm environment. However, there was no effect of dietary lipid supplementation in these two fat depots. Metabolic heat production, and energy and nitrogen excretion by animals were increased (P < 0.05) by cold exposure while lipid supplementation had the opposite effect (P < 0.05). The relationship between average daily gain and feed intake was linear at both warm and cold environments, but with higher (P < 0.05) average daily gain at all levels of intake in the cold compared to the warm environment. Results indicate that both environment and diet regulate metabolic activity in sheep. However, there were differences in lipogenic response by tissues to the treatments. Key words: Environmental temperature, dietary lipid, fatty acid synthesis, metabolic rate, sheep

scholarly journals Hepatic lipogenesis in young rats given proteins of different quality

1984 ◽  
Vol 52 (1) ◽  
pp. 131-137 ◽  
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.

Fatty acid synthesis in adipose tissues of physically trained rats in vivo

1983 ◽  
Vol 245 (1) ◽  
pp. E8-E13
Author(s):  
K. Tokuyama ◽  
H. Okuda
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Physical Training ◽  
Dark Period ◽  
Acid Synthesis ◽  
Free Access ◽  
Adipose Tissues ◽  
Brown Adipose

The effect of physical training on fatty acid synthesis in vivo was studied. After the rats had free access to a running wheel for 50 days, the rate of fatty acid synthesis estimated using 3H2O in adipose tissues of trained rats was about three times higher than that of sedentary rats in both the light and dark period. The rate of fatty acid synthesis in the liver but not in the brown adipose tissue was also slightly enhanced by physical training. The number of adipocytes was not affected, but the size of adipocytes was reduced by physical training. In trained rats, the rate of fatty acid synthesis in adipocytes whose diameter was similar to that of sedentary rats was about 10 times higher than that of sedentary rats. Within adipose tissue, the rate of fatty acid synthesis correlated positively to the diameter of adipocytes both in the sedentary and trained rats. These findings mean that the adaptive increase in fatty acid synthesis seen in adipocytes of trained rats is not secondary to the reduction in size of adipocytes.

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