Lipogenesis from ketone bodies in the perfused rat liver: effects of acetate and ethanol

1987 ◽  
Vol 65 (11) ◽  
pp. 989-996 ◽  
Author(s):  
Gerda Endemann ◽  
Patrick G. Goetz ◽  
John F. Tomera ◽  
William M. Rand ◽  
Sylvain Desrochers ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Ketone Body ◽  
Ketone Bodies ◽  
The Other ◽  
Ethanol Metabolism ◽  
Perfused Rat Liver ◽  
Other Hand

The interactions between acetate or ethanol metabolism, lipogenesis, and ketone body utilization have been studied in isolated livers from fed rats perfused with 15 mM glucose and 10 mM acetate or ethanol. The contribution of acetate to ketogenesis is constant; on the other hand, the contribution of ethanol to ketogenesis increases with time, presumably because of the accumulation of acetate in the perfusate. Ketogenesis is decreased in the presence of ethanol (but not acetate), while ketone body utilization is not affected by ethanol or acetate. Acetate contributes one third and ethanol contributes one half of the carbon incorporated into fatty acids and 3-β-hydroxysterols. Only a small fraction (less than 5%) of the incorporation of acetate or ethanol into fatty acids and sterols occurs via transient incorporation into ketone bodies.

scholarly journals Fatty acid metabolism in the perfused rat liver

1970 ◽  
Vol 119 (3) ◽  
pp. 525-533 ◽  
Author(s):  
H. A. Krebs ◽  
R. Hems
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Ketone Body ◽  
Unsaturated Fatty Acids ◽  
Ketone Bodies ◽  
Saturated Fatty Acids ◽  
Perfused Rat Liver ◽  
Body Formation ◽  
Body Production ◽  
Chain Fatty Acids

1. The formation of acetoacetate, β-hydroxybutyrate and glucose was measured in the isolated perfused rat liver after addition of fatty acids. 2. The rates of ketone-body formation from ten fatty acids were approximately equal and independent of chain length (90–132μmol/h per g), with the exception of pentanoate, which reacted at one-third of this rate. The [β-hydroxybutyrate]/[acetoacetate] ratio in the perfusion medium was increased by long-chain fatty acids. 3. Glucose was formed from all odd-numbered fatty acids tested. 4. The rate of ketone-body formation in the livers of rats kept on a high-fat diet was up to 50% higher than in the livers of rats starved for 48h. In the livers of fat-fed rats almost all the O2 consumed was accounted for by the formation of ketone bodies. 5. The ketone-body concentration in the blood of fat-fed rats rose to 4–5mm and the [β-hydroxybutyrate]/[acetoacetate] ratio rose to 11.5. 6. When the activity of the microsomal mixed-function oxidase system, which can bring about ω-oxidation of fatty acids, was induced by treatment of the rat with phenobarbitone, there was no change in the ketone-body production from fatty acids, nor was there a production of glucose from even-numbered fatty acids. The latter would be expected if ω-oxidation occurred. Thus ω-oxidation did not play a significant role in the metabolism of fatty acids. 7. Arachidonate was almost quantitatively converted into ketone bodies and yielded no glucose, demonstrating that gluconeogenesis from poly-unsaturated fatty acids with an even number of carbon atoms does not occur. 8. The rates of ketogenesis from unsaturated fatty acids (sorbate, undecylenate, crotonate, vinylacetate) were similar to those from the corresponding saturated fatty acids. 9. Addition of oleate together with shorter-chain fatty acids gave only a slightly higher rate of ketone-body formation than oleate alone. 10. Glucose, lactate, fructose, glycerol and other known antiketogenic substances strongly inhibited endogenous ketogenesis but had no effects on the rate of ketone-body formation in the presence of 2mm-oleate. Thus the concentrations of free fatty acids and of other oxidizable substances in the liver are key factors determining the rate of ketogenesis.

scholarly journals Rates of ketone-body formation in the perfused rat liver

1969 ◽  
Vol 112 (5) ◽  
pp. 595-600 ◽  
Author(s):  
H. A. Krebs ◽  
Patricia G. Wallace ◽  
R. Hems ◽  
R. A. Freedland
Keyword(s):  
Fatty Acids ◽  
Rat Liver ◽  
Ketone Bodies ◽  
Short Chain Fatty Acids ◽  
Diabetic Rats ◽  
Isolated Perfused Rat Liver ◽  
Perfused Liver ◽  
Perfused Rat Liver ◽  
Normal Range ◽  
Physiological Value

1. The rates of formation of acetoacetate and β-hydroxybutyrate by the isolated perfused rat liver were measured under various conditions. 2. The rates found after addition of butyrate, octanoate, oleate and linoleate were about 100μmoles/hr./g. wet wt. in the liver of starved rats. These rates are much higher than those found with rat liver slices. 3. The differences between the rates given by slices and by the perfused organ were much higher with the long-chain than with short-chain fatty acids. The increments caused by oleate and linoleate were 12 and 16 times as large in the perfused organ as in the slices, whereas the increments caused by butyrate and octanoate were about four times as large. 4. The rates of ketogenesis in the unsupplemented perfused liver of well-fed rats, and the increments caused by the addition of fatty acids, were about half of those in the liver from starved rats. 5. The value of the [β-hydroxybutyrate]/[acetoacetate] ratio of the medium was raised by octanoate, oleate and linoleate. 6. Carnitine did not significantly accelerate ketogenesis from fatty acids. 7. Oleate formed up to 82% of the expected yield of ketone bodies. 8. In the liver of alloxan-diabetic rats the endogenous rates of ketogenesis were raised, in some cases as high as in the liver from starved rats, after addition of oleate. 9. On addition of either β-hydroxybutyrate or acetoacetate to the perfusion medium the liver gradually adjusted the [β-hydroxybutyrate]/[acetoacetate] ratio towards the normal range. 10. The [β-hydroxybutyrate]/[acetoacetate] ratio of the medium was about 0·4 when slices were incubated, but near the physiological value of 2 when the liver was perfused. 11. The experiments demonstrate that for the study of ketogenesis slices are in many ways grossly inferior to the perfused liver.

scholarly journals Ganglioside incorporation and release by the isolated perfused rat liver

1991 ◽  
Vol 274 (2) ◽  
pp. 581-585 ◽  
Author(s):  
S C Kivatinitz ◽  
A Miglio ◽  
R Ghidoni
Keyword(s):  
Rat Liver ◽  
The Other ◽  
Regulatory Role ◽  
Isolated Perfused Rat Liver ◽  
Order Kinetic ◽  
Perfused Rat Liver ◽  
Ganglioside Gm1 ◽  
First Order ◽  
Pseudo First Order

The fate of exogenous ganglioside GM1 labelled in the sphingosine moiety, [Sph-3H]GM1, administered as a pulse, in the isolated perfused rat liver was investigated. When a non-recirculating protocol was employed, the amount of radioactivity in the liver and perfusates was found to be dependent on the presence of BSA in the perfusion liquid and on the time elapsed after the administration of the ganglioside. When BSA was added to the perfusion liquid, less radioactivity was found in the liver and more in the perfusate at each time tested, for up to 1 h. The recovery of radioactivity in the perfusates followed a complex course which can be described by three pseudo-first-order kinetic constants. The constants, in order of decreasing velocity, are interpreted as: (a) the dilution of the labelled GM1 by the constant influx of perfusion liquid; (b) the washing off of GM1 loosely bound to the surface of liver cells; (c) the release of gangliosides from the liver. Process (b) was found to be faster in the presence of BSA, probably owing to the ability of BSA to bind gangliosides. The [Sph-3H]GM1 in the liver underwent metabolism, leading to the appearance of products of anabolic (GD1a, GD1b) and catabolic (GM2, GM3) origin; GD1a appeared before GM2 and GM3 but, at times longer than 10 min, GM2 and GM3 showed more radioactivity than GD1a. At a given time the distribution of the radioactivity in the perfusates was quite different from that of the liver. In fact, after 60 min GD1a was the only metabolite present in any amount, the other being GM3, the quantity of which was small. This indicates that the liver is able to release newly synthesized gangliosides quite specifically. When a recirculating protocol was used, there were more catabolites and less GD1a than with the non-recirculating protocol. A possible regulatory role of ganglioside re-internalization on their own metabolism in the liver is postulated.

Regulation by Insulin and Free Fatty Acids of Pyruvate Dehydrogenase Activity in Perfused Rat Liver

1977 ◽  
Vol 5 (4) ◽  
pp. 1000-1001 ◽  
Author(s):  
DAVID L. TOPPING ◽  
M. ANWAR GOHEER ◽  
HALDANE G. COORE ◽  
PETER A. MAYES
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Dehydrogenase Activity ◽  
Rat Liver ◽  
Pyruvate Dehydrogenase ◽  
Perfused Rat Liver

The ability of ectomycorrhizal fungi to utilize fatty acids and a lipid as a carbon source for mycelial growth

2003 ◽  
Vol 81 (12) ◽  
pp. 1285-1292 ◽  
Author(s):  
Takefumi Hattori ◽  
Akira Ohta ◽  
Masayuki Itaya ◽  
Mikio Shimada
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Ectomycorrhizal Fungi ◽  
Mycelial Growth ◽  
The Other ◽  
Other Hand ◽  
The Family ◽  
Ecm Fungi ◽  
Relative Utilization

We have investigated growth of ectomycorrhizal (ECM) fungi (i.e., 55 strains of 32 species in 15 genera) on saturated (palmitate), monounsaturated (oleate), diunsaturated (linoleate), triunsaturated (linolenate) fatty acids, and the triacylglyceride of oleate (triolein) lipid to elucidate an ability to utilize the fatty acids and lipid as a carbon source for growth. Relative utilization ratios (URs, %) based on mycelial growth on glucose suggest that ECM fungi belonging to the family Thelephoraceae have an ability to utilize palmitate. On the other hand, ECM fungi in the genus Laccaria can utilize at least either palmitate or oleate. Furthermore, Hygropharus russula grows on palmitate, oleate, and slightly on triolein. Lactarius chrysorrheus grows only on palmitate. These fatty-acid- and lipid-utilizing fungi may be promising as model fungi for further elucidation of the metabolic ability to utilize the fatty acids and lipid as a carbon source. On the contrary, the fungi in the genus Suillus were shown to scarcely utilize the fatty acids and lipid. Furthermore, most ECM fungi did not grow on either linoleate or linolenate.Key words: carbon source, ectomycorrhizal fungi, fatty acid, lipid, mycelial growth.

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